STS-93 MISSION ARCHIVE (COMPLETE) Updated: 07/31/99 Shuttle Columbia and the Chandra X-ray Observatory By William Harwood CBS News/Kennedy Space Center The following copy originally was posted on the Current Mission space page at http://www.cbs.com/network/news/space/current.html. Comments, suggestions and corrections welcome! TABLE OF CONTENTS -NASA mulls impact of Air Force IUS anomaly (04/15/99) -Chandra launch date still uncertain (05/18/99) -Collins fields questions about historic role (06/23/99) -Detailed mission preview (07/16/99) -Shuttle crew arrives; countdown begins (07/16/99) -NASA managers assess Chandra capacitor issue (07/17/99) -NASA clears Columbia, Chandra telescope for Tuesday launch (07/19/99) -Shuttle launch scrubbed at T-minus seven seconds (07/20/99) -Second launch attempt delayed by thunderstorms (07/21-22/99) -Shuttle rockets into orbit; crew launches space telescope (07/22-23/99) -Short circuit no problem for re-entry, NASA says (07/24/99) -X-ray telescope carries out successful rocket firing (07/24/99) -NASA assesses threat of possible main engine nozzle leak (07/25/99) -Shuttle commander cagey about future with NASA (07/25/99) -Collins looks forward to landing (07/26/99) -X-ray telescope completes second of five critical rocket firings (07/26/99) -Shuttle Columbia returns to Earth (07/27-28/99) -Engine leak blamed on debris impact (07/30/99) =================================================================== NASA mulls impact of Air Force IUS anomaly (04/15/99) Launch of NASA's $1.46 billion Chandra X-ray Observatory, currently targeted for July 9, could be delayed pending the outcome of an Air Force investigation into the failure of an upper stage rocket April 9 that left a missile warning satellite stranded in the wrong orbit. While Chandra will be carried into low-Earth orbit aboard the shuttle Columbia, it requires a $70.9 million Boeing-built Inertial Upper Stage booster, or IUS, to get into its final highly elliptical orbit. But the second stage of a similar two-stage solid-fuel IUS misfired during launch of a $250 million Defense Support Program satellite April 9. Whether the second stage fired at all is unclear - the Air Force refuses to discuss the booster's performance other than to say a malfunction occurred - but the mishap already is impacting Chandra launch processing. Scott Higginbotham, an engineer at the Kennedy Space Center overseeing the telescope's ground processing, said engineers had hoped to attach Chandra to IUS-27 on April 23. But the booster and its flight support hardware, currently at the Cape Canaveral Air Station, have been impounded for the Air Force investigation. Whenever the rocket is released, technicians will face another six days of delayed work to ready the booster for mating with Chandra. That's assuming, of course, no modifications are required based on analysis of the Air Force failure. Senior NASA and Chandra project managers have asked the Air Force to release IUS-27 as soon as possible to permit processing in parallel with the mishap investigation to preserve any chance of making the July 9 launch date. "They would like to go ahead and press forward and accept the risk they might have to back up" if any modifications ultimately are required, Higginbotham said. Robert Hughes, NASA's upper stage project manager at the Marshall Space Flight Center in Huntsville, Ala., was at the Kennedy Space Center this week as a mishap review board member and could not be reached for comment. Along with interrupting ground processing at the Kennedy Space Center, the Air Force probe also has delayed training for Columbia's mission, known as STS-93. Lead flight director Bryan Austin said one and probably two joint integrated simulations involving the astronauts, shuttle flight controllers and IUS controllers at Sunnyvale, Calif., have been delayed because IUS controllers and engineers are tied up with the investigation. "In terms of immediate impact to 93, we were planning a two-day long sim starting April 14 that would involve all the different control centers, a joint integrated simulation with everybody," Austin said on April 13. "That was going to be a big deal. That has been postponed because the Sunnyvale Air Force folks and the Boeing IUS people were going to be taken away initially to be part of the investigation. So that exercise has been put on hold. "We're still working toward the ninth and we don't have any information yet to say this IUS problem will definitely push our launch back," he added. "So we've got to keep working toward it. But that kind of put a wrench in things in terms of our sim schedule." The goal is to stage two joint integrated simulations before launch of shuttle mission STS-96 on May 20 and then two more before July 7. Austin said he hopes to reschedule the delayed simulations around the end of April or early May. "From the crew's standpoint, training and flight control preparation, it doesn't impact us a bit, yet," he said. "If we can't do any training because people are tied up until after 96 and then all the sudden we've got one month to do a bunch of sims, from my perspective I think that's a threat to the launch from a [flight control] training readiness standpoint." In the meantime, details about what went wrong April 9 remain sketchy. The $250 million Defense Support Program missile early warning satellite was boosted into low-Earth orbit by a Lockheed Martin Titan 4B rocket making its first flight since a spectacular $1 billion failure last August. DSP-19 and its two-stage IUS separated normally and the IUS first stage fired as planned. Several hours later, the IUS second stage was scheduled to fire to place DSP-19 in a circular orbit 22,300 miles up. But something went wrong. The rocket either failed to fire at all or misfired in some fashion, placing DSP-19 in a highly elliptical orbit. Air Force public affairs officers refuse to provide any information on the IUS beyond saying the first stage did, in fact, fire on schedule. One public affairs officer said the resulting orbit was "very similar" to what one would expect if only the first stage had fired. While flight controllers were able to command the satellite, it was spinning faster than expected after release from the IUS and they elected not to deploy its main solar arrays pending additional analysis. Solar cells on the body of the satellite presumably generate some level of power, but it's not yet known how long the satellite can operate in that fashion or whether enough on-board fuel is available to put the craft in a useable orbit. As it now stands, the orbit is unknown. The Orbital Information Group at NASA's Goddard Space Flight Center includes DSP-19 (listed as USA 142) and the two IUS stages, but it does not provide any orbital elements, the numbers used by satellite tracking programs to locate a spacecraft. Elements for the Titan 4 second stage rocket body, however, are provided. TITAN 4 R/B 1 25670U 99017B 99104.50830418 .00343297 -55879-5 42865-3 0 119 2 25670 28.6259 243.0276 0393167 127.4369 236.2657 15.36182539 733 IUS (1) 1 25671U 99017C No Elements Available IUS (2) 1 25672U 99017D No Elements Available USA 142 1 25669U 99017A No Elements Available In addition, a bit of debris from the DSP-19 satellite was added to the list April 14, listed as 25675 USA 142 DEB. No elements were provided. At the top of the OIG web page, a boldface note warns that "As the result of a joint request from USSPACCOM, NRO, Pentagon, and other sources some objects have been removed from the OIG systems. This request was approved by NASA HQ. These objects were removed because they were deemed to be 'sensitive satellites.'" Austin said NASA flight controllers were overjoyed to see the Titan 4B take off with DSP-19 on board because training for the shuttle flight had been interrupted on several occasions by Air Force IUS training. "It was such a high seeing the thing finally launch and it just comes back to slap you," Austin said. Training for Chandra's deployment is especially crucial because NASA has not launched an IUS since 1995 and "there's been a lot of change in the expertise level collectively," Austin said. "For the most part, IUS deploy and procedures are the same," he said. "But something that to me has been a struggle for this flight with some of our IUS friends is to get them to realize that the payload on the other end of the IUS is not the typical thing the shuttle has been doing." Once the Chandra/IUS begins operating on battery power just before launch from the shuttle Columbia, "this payload has to be deployed," Austin said, because of power and temperature constraints. "It cannot come home," he said. "It's either going to be orbiting space trash or it's going to go out and do its mission." Grant Cates, the NASA engineer in charge of Columbia's ground processing, said if worse comes to worse, the Chandra mission could slip to late August or perhaps even early September without causing a major disruption for downstream shuttle flights. While one of NASA's two shuttle launch pads - LC-39A - has been out of action in recent months for routine refurbishment, the facility is scheduled to return to service Aug. 3. Columbia and Chandra are scheduled to use launch complex 39B. The next flight on NASA's manifest, launch of a shuttle radar mapping mission Sept. 16, is scheduled to depart from LC-39A. NASA originally hoped to launch Chandra in April, but the flight was delayed because of flawed circuit boards in the telescope. Liftoff is now scheduled for 1:19 a.m. EDT on July 9 followed seven hours later by deployment of the Chandra observatory around 8:30 p.m. Landing back at the Kennedy Space Center is expected around 12:19 a.m. for a mission duration of four days and 23 hours. Columbia's mission is now nearly a full year behind schedule because of a series of technical problems that have plagued the X-ray observatory. Here is a discussion of the Chandra ciruit board problem originally written for Space News magazine: By WILLIAM HARWOOD CAPE CANAVERAL, Fla. - Launch of the year's first shuttle flight, an already delayed mission to deploy a $1.5 billion X-ray telescope, will be delayed another five weeks - and possibly longer - to replace flawed circuit boards in the costly spacecraft. NASA already was spending $39 million above the satellite's original price tag to fix problems with critical computer control software that delayed launch from last August to April 8. The latest delay will cost the agency an estimated $1.6 million a week, or an additional $8 million assuming the Chandra X-ray Observatory can, in fact, be ready for launch aboard the shuttle Columbia by mid May. Even if it can, the long-awaited flight will be in conflict with NASA's second flight of 1999, a planned mid-May mission to deliver supplies and equipment to the International Space Station. Several launch options are being mulled. But senior NASA managers said the agency likely would proceed with the May space station mission and instead delay launch of the Chandra X-ray Observatory into the summer time frame, putting it almost a year behind schedule and driving the project's final cost even higher. That would almost certainly force NASA to revise plans for the next Hubble Space Telescope servicing mission, currently scheduled for launch Aug. 17, 2000, aboard Columbia. Columbia, NASA's oldest space shuttle, is scheduled for 10 months of major modifications, structural inspections and routine maintenance starting immediately after the Chandra mission. Additional launch delays now translate into corresponding delays for the Hubble mission, Columbia's next flight after servicing. But Hubble engineers are worried about the health of the showcase satellite. Only four of Hubble's six stabilizing gyroscopes are operational and three are required for science operations. Additional failures are possible and engineers want to service the satellite as soon as possible. Bill Readdy, deputy associate administrator for shuttle operations at NASA headquarters, said Jan. 20 NASA is considering the possibility of shifting the Hubble repair mission from Columbia to the Endeavour or Atlantis because of Chandra's problems. In the near term, the possible conflict with the May space station mission could end up moot. The Hubble-class Chandra could be delayed much longer than five weeks if additional circuit board problems are identified during testing by satellite-builder TRW Space and Electronics Group of Redondo Beach, Calif. Making sure the telescope is problem free at launch is critical. Unlike the Hubble Space Telescope, which can be visited by shuttle repair crews, Chandra will be boosted by a solid-fuel booster into an extreme elliptical orbit with a high point of 140,000 kilometers and a low point of 10,000 kilometers. "To us, failure is not an option," Kenneth Ledbetter, a senior manager in NASA's office of space science, said Jan. 20. "We must make sure [Chandra] is ready to launch and will function when it's launched. Because unlike Hubble, it's not serviceable. It goes into a very high orbit and will not be reachable by the shuttle once it's launched." Originally known as the Advanced X-ray Astrophysics Facility, Chandra is one of NASA's four so-called "Great Observatories," designed to study X-ray emissions from particularly violent deep space targets. Launch originally was targeted for last August, but the flight was repeatedly delayed because of work to correct problems in the satellite's complex computer control software. While it took longer than originally expected, the problems eventually were resolved and TRW held an official roll out ceremony Jan. 14. At that time, the company planned to ship the spacecraft to the Kennedy Space Center for final processing on Jan. 28. But the day after rollout, NASA managers were notified by TRW that a subcontractor, BF Goodrich of Akron, Ohio, had discovered problems with critical circuit boards used in another TRW satellite being built for Korea that were similar to those aboard Chandra. The suspect boards were built by Gulton Data Systems of Albuquerque, N.M. The company was purchased by BF Goodrich in March 1997, after the boards in question had been built, according to Goodrich spokesman Rob Jewell. In any case, engineers discovered copper plating used to ensure electrical connections between the layers making up a given circuit board had a tendency to separate, breaking critical connections. Ledbetter said Chandra is equipped with six electronic data systems, which utilize 129 circuit boards. Twenty-two of those boards were suspect. Engineers quickly determined that two circuit boards in Chandra's primary command and telemetry control system were possible victims of the plating problem. As a result, the telescope will be shipped to Florida in early February without the command and telemetry unit, which will be repaired and re-installed later. Samples from circuit boards similar to the remaining 20 suspect boards installed aboard Chandra are being subjected to a battery of tests late to determine their flight worthiness. The idea is to simulate the hot-cold cycles the spacecraft sill experience throughout its planned orbital lifetime. The idea was "to try to beat the hell out of those boards to see if we can get any effects to emerge," said a spokesman for TRW. "Those tests are underway as we speak." Columbia's mission is a throwback of sorts to early short-duration shuttle flights, a four-day 23-hour mission in which the primary payload will be deployed seven hours and 17 minutes after launch. A two-stage Boeing-built Inertial Upper Stage solid-fuel booster is scheduled to fire one hour later to begin the Chandra observatory's boost to its final elliptical orbit. The rest of the flight will be devoted to on-board research. While the flight might be shorter than most, interest will be high because of the presence of shuttle commander Eileen Collins, the first female to command a space shuttle mission. Her crewmates are rookie pilot Jeff Ashby, Catherine Coleman, flight engineer Steven Hawley and Frenchman Michel Tognini. Collins will be making her third space flight, Coleman and Tognini their second each and Hawley his fifth. =================================================================== Chandra launch date still uncertain (05/18/99) With the shuttle Columbia's launch delayed to at least late July, NASA managers continue to assess the impact of an upper stage failure that left an Air Force early warning satellite in the wrong orbit. Columbia's crew had been scheduled for takeoff July 9 to ferry the $1.5 billion Chandra X-ray Observatory and its $70 million Boeing Inertial Upper Stage - IUS - rocket booster into orbit. But an IUS malfunctioned April 9 during launch of an Air Force Defense Support Program satellite by a Titan 4 rocket. The two stages of the solid-fuel IUS apparently failed to separate cleanly, a malfunction that would doom NASA's costly Chandra. Few details about the Air Force failure have been released, but here's part of a statement issued by Air Force Space Command at Peterson Air Force Base, Colo.: "At T+8 minutes after liftoff, the Titan 4B booster separated from the IUS. Indications are that the IUS and the satellite were placed in the required low Earth orbit. Approximately one hour and 15 minutes after liftoff, the IUS SRM 1 fired to initiate the transfer orbit. Indications are that SRM 1 performed as expected. "At six hours and 30 minutes after liftoff, stage one and stage two of the IUS were scheduled to separate. Data shows several anomalous events occurred during the separation sequence. Although two separation break wires indicate separation had occurred, a separate connector continued to cary signals, indicating the separation was not complete. "Under normal conditions, stage two extends a compressed nozzle called the extendable exit cone after separation. When the extenders reach a certain pressure they swing away or disengage and that is taken as a signal that the cone is fully extended. In this case, one of the extenders disengaged within two seconds after receiving its command. Normally, the expected duration for a full extension is seven to eight seconds. The other two extenders did not indicate full extension until after SRM 2 fired. "Telemetry then shows large pitch, yaw and roll attitude errors occurring after SRM 2 was fired. In effect, the data shows the vehicle and satellite tumbling in their transfer orbit. The stack attempted to regain control, but failed to do so. The satellite was separated from the IUS second stage, but remained in a complex tumble in a highly elliptical orbit." The IUS slated for use by Chandra is at the Cape Canaveral Air Station adjacent to the Kennedy Space Center. It's not yet known what might have to be done to ensure it is safe for flight as is or what repairs might be necessary. =================================================================== Collins fields questions about historic role (06/23/99) Veteran shuttle pilot Eileen Collins, the first woman to command a space shuttle mission, said today she's proud of her role but insisted gender did not help or hinder her advancement through NASA's traditionally male-dominated astronaut corps. "I'm honored to be the first woman to have an opportunity to command the shuttle," Collins said during a media photo opportunity at the base of launch pad 39B. "I started as a pilot in the military back in 1978 and things have changed as far as the available jobs that women are able to apply for and be accepted into. There were a lot more restrictions back then and I knew it wasn't all going to change at once. "For example, graduating from pilot training in 1979, the majority of the airplanes in the Air Force inventory I could not apply to fly," she said. "I knew it was going to be an evolutionary process and if our generation of women did our jobs, did them good, did them right, really stayed professional with everything we did, then eventually those opportunities would open. And they did. In 1993, the Secretary of Defense lifted the last restriction in the Air Force on women flying combat aircraft such as fighters and bombers. Now those opportunities are open to women and I think that's the way it should be. I'm glad that I've had the opportunity to be part of bringing those barriers down." As for how she's fared since joining NASA nearly 10 years ago, Collins said "you don't go to work thinking you're different because you're a woman and you might be treated differently. It just doesn't happen that way. We are so focused on the mission those things just don't enter the picture and that's the way it should be." Collins and her crewmates - pilot Jeffrey Ashby, flight engineer-astronomer Steven Hawley, Catherine "Cady" Coleman and French astronaut Michel Tognini - are tentatively scheduled for blastoff aboard the shuttle Columbia at 12:36 a.m. on July 20, the 30th anniversary of the Apollo 11 moon landing. The goal of the 95th shuttle mission, the second of five flights planned for 1999, is deployment of the $1.5 billion Chandra X-ray Observatory, the third of four so-called "Great Observatories" NASA is launching to study the universe across the electromagnetic spectrum. If all goes well, Chandra and its two-stage solid-fuel booster will be released from a cradle in Columbia's cargo bay at 7:53 a.m. on July 20, seven hours and 17 minutes after launch. One hour later, the first stage of Chandra's $70 million Boeing-built Inertial Upper Stage booster will fire to begin the spacecraft's trip to a high elliptical orbit with a low point of about 6,000 miles and a high point of some 87,000 miles. Once on station, Chandra will study some of the most violent objects in the universe, from black holes to quasars, by recording X-rays that cannot penetrate Earth's atmosphere. "To put it in perspective, when I was a kid I had a four-and-a-half-inch reflecting telescope in my backyard, which I used to use all the time," Hawley said. "And when I grew up to be a professional astronomer, I had the opportunity to use the 200-inch [telescope] at Mount Palomar. The difference between those two telescopes, I think, kind of characterizes the difference between where X-ray astronomy was and where it will be when Chandra's in orbit. It's a major facility comparable to what ground-based optical astronomers have been doing for a long time." Collins and her crew flew to the Kennedy Space Center on Monday to participate in a terminal countdown demonstration test, or TCDT, a routine part of pre-launch training. They plan to strap in aboard Columbia Thursday for a dress rehearsal countdown before flying back to Houston to begin final preparations. "We have been training, working hard, studying, we want this to be the most successful mission this could possibly be and we're going to make it successful, we're going to make it a great mission," Collins said. "And I think it's good to have a challenge like that because it just motivates you and makes you want to work harder." For good or ill, Collins' role as the first female shuttle commander is generating much more media interest than usual. Her crewmates, at least, say she's handled the added pressure with style. "Certainly, there's a lot of attention focused on Eileen's assignment as commander and the milestone it represents in our country's history in the progression of women," Ashby said. "I think that's wonderful. Eileen is a very easy person to work for and has made me feel very comfortable and treated me not like a rookie but as somebody who has flown before and I really respect her for that. So I'm very, very pleased to be assigned to this crew and to be flying with Eileen Collins." Added Coleman: "Eileen's just trying to do her job. At the same time, I'm actually very excited about the historical significance, not for me, not for Eileen, but for the little girls out there. Because they're going to see the publicity that surrounds this flight and it's going to really bring home the fact to them that if Eileen can do what she set out to do ... if we can achieve these dreams, then a lot of the folks out there can achieve their dreams also. And especially the young girls. I think it's going to really help make sure they realize the world is theirs." Chandra's flight has been repeatedly delayed. It originally was scheduled for launch last August, but the mission was put on hold to correct problems with the observatory's computer control software. Launch then was reset for April 9 but the flight was delayed again, this time to July 9, to replace suspect circuit boards in the telescope. It was delayed yet again when the Boeing-built Inertial Upper Stage booster used to help launch an Air Force missile early warning satellite failed in early April. Chandra is equipped with a similar IUS booster and its launch was put on hold pending resolution of the Air Force failure investigation. The Air Force has not yet released its findings, but officials have said the two stages of the solid-fuel booster failed to separate cleanly. As of this writing, it's not known what, if anything, had to be done to Chandra's IUS but NASA managers say it has been cleared for flight. NASA moved the latest launch target up to July 20 to provide as much time as possible to get Columbia off the ground before the Eastern Range shuts down in August for upgrades and maintanence. Complicating the picture, Columbia itself is overdue for regular maintenance, upgrades and structural inspections at a Boeing facility in Palmdale, Calif. If the shuttle isn't off the ground by mid August, officials say, the launch could be delayed to late 2000. =================================================================== NASA set to launch next 'Great Observatory' (07/16/99) Editor's Note... Portions of the following story were originally written for Astronomy Now magazine By WILLIAM HARWOOD CBS News Space Consultant KENNEDY SPACE CENTER, Fla. - Thirty years after the Apollo 11 moon landing, NASA is finally poised to launch a space mission with a woman at the controls. A mother, veteran test pilot and former Air Force Academy math instructor, commander Eileen Collins and four crewmates are scheduled to blast off aboard shuttle Columbia at 12:36 a.m. July 20 to ferry the $1.6 billion Chandra X-ray Observatory into orbit. Chandra is the most powerful X-ray telescope ever built, the centerpiece of a $2.78 billion project to study some of the most violent objects in the universe, from black holes to ancient quasars shining in the depths of space and time. On any other mission, the Hubble-class Chandra, one of the most expensive payloads ever launched by NASA, would be the clear focus of shuttle flight STS-93. But Collins' role as the first female commander has dominated media coverage. And that's OK with her. "I'm honored to be the first woman to have an opportunity to command the shuttle," Collins said during a media photo opportunity at the base of launch pad 39B. "I started as a pilot in the military back in 1978 and things have changed as far as the available jobs that women are able to apply for and be accepted into. ... I'm glad that I've had the opportunity to be part of bringing those barriers down." She is not the first female space commander. That honor goes to Valentina Tereshkova, an amateur skydiver and textile factory worker who took off aboard the single-seat Soviet Vostok 6 capsule in June 1963. Little more than a passenger, Tereshkova logged more time in space during her single three-day flight than all of NASA's Mercury astronauts combined. But of the 36 women who have ever been in space - 352 different men have flown - Collins is the first female commander with any real responsibility. And while the unusual media attention is a bit distracting, crewmate Cady Coleman said in this case, the hype has a positive result. "Little kids need to see Eileen Collins in the front seat of the shuttle, landing the shuttle as the commander," she said. "They need to see that. Number two is their parents. Their parents are the people who provide the kids with vision. And the parents need to see that this is the deal now, women and minorities can have any job they are capable of holding. I just see this as a really positive experience." SPACE DEMOGRAPHICS CURRENT..POST STS-93 388......389.......Different people have flown in space 29.......29........Nations represented in space 352......353.......Men 36.......36........Women 813......818.......Total tickets 242......243.......Americans 214......215.......American men 28.......28........American women 72.................Soviets 70.................Soviet men 2..................Soviet women 20.......20........Commonwealth of Independent States 19.......19........CIS men 1........1.........CIS woman 54.......54........Men and women from non-space faring nations 49.......49........Men 5........5.........Women Astronaut/Flights 4........4.........Men with six flights 0........0.........Women with six flights 8........9.........Men with five flights 3........3.........Women with five flights 37.......36........Men with four flights 3........3.........Women with four flights 64.......64........Men with three flights 9........10........Women with three flights 95.......96........Men and women with two flights 165......164.......Men and women with one flight Collins's role aside, launching Chandra is the primary goal of the 95th shuttle mission and if all goes well, the 12,930-pound observatory will be gently ejected from the orbiter's cargo bay seven hours and 17 minutes after launch. Assuming a nerve-wracking month of rocket firings, instrument checkout and engineer tests goes smoothly, Chandra will begin making test observations of high-priority X-ray targets 20 to 25 days or so after release. If all goes well, around-the-clock science operations will begin shortly after a slew of orbital verification tests are complete. If all goes well, that is. Unlike the Hubble Space Telescope, the Compton Gamma Ray Observatory and other spacecraft that circle the globe in relatively low orbits, Chandra is the result of compromises and budget cuts. To save money, the spacecraft was designed to operate in a highly elliptical orbit with a high point, or apogee, of some 87,000 miles and a low point, or perigee, of about 6,000 miles. The good news about the orbit is that Chandra will be able to operate near continuously, high above Earth's obscuring radiation belts, taking data for up to 55 hours of each 64-hour orbit. The bad news is that it will be far beyond the reach of shuttle astronauts if anything goes wrong. Hubble was launched with an improperly ground mirror, but a shuttle crew later was able to install corrective optics that turned what could have been a world-class failure into a stunning success. No such repairs will be possible with Chandra once the telescope is ejected from Columbia's cargo bay. "We've done everything humanly possible to ensure we're going to have a successful launch," said Edward Weiler, NASA's associate administrator for space science. "But again, let me remind everybody, this is not a trip to grandma's on a summer afternoon. We are launching a space shuttle, we're going into space with a very large payload, the largest civilian payload ever launched on the shuttle, it's high-tech stuff and there are always risks." Chandra Project Scientist Martin Weisskopf, who has spent more than 20 years on the project, reflected the thoughts of many when he said in an interview, "We're extremely nervous, as everyone is who goes through launches. There are things that have to work more or less right. If you start to think about the enormity of it all, you get very nervous." A Complex Launch Scenario The 45.3-foot-long Chandra, built by TRW Space and Electronics Group, will make the initial climb into space nestled in Columbia's cargo bay. An hour and a half after liftoff, the shuttle's payload bay doors will crank open, exposing Chandra and it's Boeing-built $76 million solid-fuel Inertial Upper Stage - IUS - booster to open space. A similar booster malfunctioned during an Air Force Titan 4 launch in April, stranding a missile early warning satellite in a useless orbit. While the results of the failure investigation have not yet been released, NASA managers participated in the review and said only minor modifications were needed to ensure Chandra's IUS will perform properly. While some lingering concern will no doubt remain as flight controllers await ignition of the powerful rocket motor, the first item on the agenda will be making sure Chandra itself is healthy before cables providing power from the shuttle are retracted. That is the point of no return. "The Chandra, from our standpoint, is very thermally challenging in that they've got a lot of constraints while they're in the bay," said lead flight director Bryan Austin at the Johnson Space Center in Houston. "We're really limited to staying in a bay-down, facing-the-Earth, tail-forward attitude up until the time where we point the orbiter to the deploy position. They don't want to get too hot or too cold." Those thermal constraints are the result of budget cutbacks and technical tradeoffs in years past that forced engineers to design a spacecraft tailored specifically for the environmental conditions it will experience in its final planned orbit. Until it gets there, the project has very little margin for error. "It really was put together to get out in a user friendly, customer friendly way on day one," Austin said. "Anything after that, depending on the failure, really constrains us and can jeopardize mission success." Once the shuttle's cargo bay doors are open, Coleman and French flier Michel Tognini, both space veterans, will begin bringing Chandra to life by powering up its electric systems. After initial checkout is complete, ground controllers at the Chandra Operations Control Center in Cambridge, Mass., will activate the spacecraft's communications system for additional checks. About two and a half hours into the mission, Coleman and Tognini will start working their way through a complex pre-deployment checklist, double checking each step. Astronomer-astronaut Steven Hawley, who launched Hubble and later helped repair it, will serve as another set of eyes in the cockpit to make sure nothing is missed. "Michel and I work as a team," Coleman said in an interview. "I put my finger on a switch, he verifies it's the right switch and that is very, very helpful to me. We also have a third person in the background, Steve Hawley, whose job is the big picture of the deploy. It's very human to make a mistake and we cannot afford that. So we're doing everything we can to prevent that." The IUS, mounted on a rotating deployment platform called a tilt table, will be switched briefly to internal power and its first stage nozzle will be commanded to slew back and forth to verify its ability to steer during powered flight. A half-hour later, tilt table actuators that will be used later to elevate the spacecraft's nose up and out of the cargo bay will be activated. Updated state vectors then will be transferred to the IUS to tell its guidance system exactly where it is located in space. After a break for lunch, Collins and pilot Jeffrey Ashby will maneuver Columbia into its final deployment orientation, aiming Chandra slightly to one side of its orbital track. The tilt table then will be raised to 29 degrees where it will remain for one full orbit while additional radio checks are made to verify antenna operation. Seven hours and five minutes into the mission, project managers will give a final "go" for deploy and a fresh state vector will be transferred to the IUS "to get it as smart as we can possibly get it," Austin said. The final deployment countdown is scheduled to begin at a mission elapsed time of six hours and 55 minutes, or about 22 minutes before release. The IUS will be switched back to internal power, umbilicals connecting the spacecraft to the shuttle will be disconnected and the tilt table will be commanded to elevate the Chandra/IUS to an angle of 58 degrees to the payload bay. The launch window will open at an MET of seven hours 16 minutes and 44 seconds. To reach the desired orbit, the first stage of the IUS must fire at a specific point in space. It can reach that point only if the spacecraft is deployed during a short, eight-minute and 45-second launch window. If the astronauts miss the window for any reason, deployment will be delayed on orbit. A subsequent delay could have more serious consequences. "If we have to keep them in the bay overnight, it really constrains things," Austin said. "If they lose any power to power their heaters that keep the [propellant] lines from freezing, it really gets kind of dicey in terms of being able to still possibly even support a mission. Because we cannot put them in a warm enough attitude to keep everything warm without hurting the [spacecraft]." Depending on the failure mode, Chandra could be deployed as late as the third day of Columbia's mission. If a problem persisted beyond that point, however, the spacecraft likely would be jettisoned because of the risk associated with bringing a fully loaded IUS back to Earth, along with a spacecraft of uncertain health loaded with toxic liquid propellant. But Chandra Deputy Project Manager Jean Olivier of NASA's Marshall Space Flight Center in Huntsville, Ala., is confident everything will go smoothly despite the make-or-break nature of the mission and the seemingly narrow margin of error. "You design to requirements," he said. "Everybody has these requirements and everybody goes off with a piece of that requirement and he builds something that will satisfy it. He doesn't want to be the bad guy that causes it not to meet its requirements, so he'll build in a little margin. And all these guys are building in a little design margin here and there. "The whole gamut of elements are going to be fraught with design margins," he added. "You really begin to understand what you've really got once you get on orbit. From a margins standpoint, we think this spacecraft is intrinsically very robust and I think we're going to find that it's even more robust than we even know today." The flight plan calls for Chandra to be gently pushed away from Columbia's tilt table at the beginning of the launch window. The IUS's on-board computer system first will orient the spacecraft in a temperature control attitude and then put it in the proper orientation for the first of two critical rocket firings. The rocket's first stage motor is programmed to ignite eight hours and 17 minutes into the mission, consuming 19,621 pounds of propellant in two minutes and five seconds. Roughly one minute after burnout, stage one will be jettisoned and stage two will ignite, burning 6,016 pounds of fuel in one minute 57 seconds. About 15 minutes after the final burn, the IUS's second stage attitude control system will begin keeping Chandra properly oriented while its two solar arrays unfold in yet another critical milestone. The spent second stage IUS motor then will be jettisoned while the solar arrays charge up Chandra's battery system. At that point, Earth sensors will be activated for several hours of observations to help the spacecraft's computer system determine its precise position in space. Chandra's initial post-IUS orbit will have an apogee of 45,906 miles and a perigee of 203 miles. When the spacecraft returns to the low point of the orbit, a liquid-fuel rocket system will fire for about 12-and-a-half minutes, raising the low point of the orbit to about 2,142 miles. Subsequent perigee and apogee firings are designed to put Chandra in its final orbit of 87,000 miles by 6,000 miles. The entire process is expected to take about 10 days. Then the real work begins. For the next two weeks or so, engineers in Cambridge will begin instrument checkout and calibration, slowly and carefully bringing Chandra to life while giving it time to adapt to the harsh environment of space. On-board X-ray sources will be used for a final calibration of Chandra's exotic mirror system to measure any internal contamination that might have developed since launch. "By that time, I can begin to now open the front aperture door," Olivier said. "I can open that door and I can now view with the aspect camera and I can start doing very precise attitude updates, go through the slews and make sure I can acquire targets down to very small angles. "Twenty days or so from the launch, you're probably in a position to actually, with a science instrument, look at a given star or a target," he said. "You're not going to do official science until orbital verification's over. But early calibration work with the science instruments will be probably on scientifically interesting targets." No one knows what Chandra will see. But Olivier is confident its pictures and spectroscopic data will be top notch and that Chandra will not experience the kind of mirror defect that initially hobbled the Hubble Space Telescope. Unlike the Hubble, "we've done end-to-end testing on this thing at an X-ray calibration facility," Olivier said. "Even before that, we had cross checks on the figure back at Perkin-Elmer, we had cross checks on the total figure of the [mirror system] and how it was aligned and all at Kodak. We have so many cross checks it would blow your mind. We may make some mistakes, but we aren't going to make that one again. We've cross checked that thing every way we can." Science Bonanza Expected The universe began with a bang and while it might one day end with a whimper, it's still an extraordinarily violent place, populated by exploding stars, powerful quasars, space-warping black holes, colliding galaxies and vast clouds of glowing million-degree gas. But studying information-rich radiation from such deep space powerhouses is difficult. While Earth's atmosphere is transparent to optical wavelengths, gamma rays and X-rays are blocked, forcing astronomers to build robotic space-based observatories to probe the inner workings of these cosmic enigmas. "It's a bit like going to a baseball game," said Chandra program scientist Alan Bunner. "If you can only see visible light, all you can see is third base and a sliver of left field. You have no idea what's going on to try to figure out what's happening in the game or even the rules of the game itself. So X radiation is one of the pieces of the puzzle we need to piece together to reveal the whole picture, to reveal the secrets of the universe and, like the rules of the ballgame, the laws of physics that make things tick." Equipped with a high-resolution camera, an imaging spectrometer and the most precisely figured X-ray mirrors ever constructed, Chandra promises nothing less than a revolution in astrophysics. "It will provide scientists with 10 to 100 times capability of any previous X-ray satellite," Weiler said. "Almost 400 years ago, Galileo's telescope represented an increase over the human eye of about a factor of 10. With that telescope, Galileo helped changed the world view of humans, that we were not at the center of the universe. "Throughout the 1990s, the Hubble Space Telescope has provided astronomers with wide-field images of the universe that are 10 times better than any ground-based telescope can produce," he continued. "Hubble has filled he astronomy text books with discoveries. But perhaps most important, it has brought science to the American public and to school kids on a regular basis and made it interesting and exciting. "Chandra has the potential to equal or even surpass these examples of previous major leaps in scientific capability. It will study the most extreme conditions in the universe: The near environment of black holes, the most powerful, continuous sources of energy in space, known as quasars, and it will test the laws of physics under conditions that are impossible to duplicate on Earth." That, of course, is what Chandra was designed to do. But if it is truly successful, Weiler said, "it will enable us to pose questions we cannot even dream of today. And that's what the adventure of science is really all about." A technical marvel, Chandra will look at pieces of the sky about the size of the sun or the full moon. In other words, its field of view will be about a half-degree across. Chandra is capable of detecting several hundred X-ray sources anywhere it points. "This observatory is a major improvement in X-ray astronomy over anything that has been done before and is to come," Weisskopf said. "The key features that make it so special are [first,] the angular resolution, it's ability to distinguish and pick out objects. The resolution of Chandra is such that you can read a newspaper at a distance of a half a mile. "Another feature is its ability to concentrate the X-rays within the core of that image," he said. "And that results from the X-ray telescope being so smooth. How smooth is it? If you took the state of Colorado and made it as smooth as these optics, the largest feature would be less than an inch high." For Weisskopf, who has labored more than 20 years to see Chandra launched, the excitement is barely endurable. "Eager is not the word," he said. "Slavering at the mouth comes to mind." Chandra is one of the crown jewels in NASA's Great Observatories program, an ambitious effort to launch a quartet of world-class telescopes capable of studying the cosmos across the electromagnetic spectrum, from high-energy gamma and X-rays to visible light and infrared radiation. The first two great observatories were launched in the early 1990s, the $1.4 billion Hubble Space Telescope and the $617 million Compton Gamma Ray Observatory. The Chandra X-ray Observatory is the third in the series while the fourth, the Space Infrared Telescope Facility, is scheduled for launch in late 2001. Chandra looks like a tapering 45.3-foot cigar with two solar panels located near the top of the telescope tube that measure 64 feet across when fully deployed. The two science instruments are mounted at the other end of the tube at the telescope's prime focus. The instrument could not utilize conventional mirrors because energetic X-rays striking at high angles would simply penetrate the surface like bullets instead of bouncing off like lower energy visible light photons. But X-rays can be focused if they hit a reflective surface at much shallower angles much like bullets will richochet off a wall. Such X-ray mirrors resemble slightly tapering barrels with highly polished internal surfaces. Chandra's mirror assembly is made up of two sets of four cylindrical mirrors coated with reflective iridium. They are the most precisely figured X-ray mirrors ever built, giving Chandra 10 times the resolution of any existing X-ray telescope and 50 times the sensitivity. If the surface of the Earth was as smooth as Chandra's mirrors, Mount Everest would be just six feet high. "It is a very substantial step forward in terms of sensitivity," said Harvey Tananbaum, director of the Chandra Science Center in Cambridge. "Factors of 10 is the equivalent on the ground of building a telescope three times larger. We're gaining not because it's the biggest telescope, we're gaining because the resolution is so great that we're focusing the signal from a point source onto a very small piece of the detector." Incoming X-rays come to a focus 32.8 feet below the mirror assembly where Chandra's science instruments are located: The High Resolution Camera and the CCD Imaging Spectrometer. In addition, the observatory is equipped with two sets of gold gratings that can be used with either instrument to record the energy spectrum of the incoming X-rays. If all goes well, initial science observations will begin about a month after launch. While the observatory's official design life is five years, engineers fully expect it to operate for a decade or more barring any major malfunctions. Among the high priority targets: Supernova remnants, galactic clusters and black hole candidates. "Black holes grab the interest of people," Tananbaum said. "But we don't really know what happens very close to a black hole and how space and time are warped. Einstein's equations make some predictions and so far, the data available seem to support that. We, the scientists, are pretty convinced that black holes actually do exist." But direct evidence is sketchy. While black holes are, by definition, unobservable, they can be studied indirectly by analyzing the radiation emitted by material as it is sucked into the gravitational maw of a given hole. As molecules of gas and dust are accelerated, they collide with increasing energy and emit X-rays just before vanishing from view. Chandra will be able to study such emissions in unprecedented detail "to really nail down black hole signatures," Weisskopf said. "We've been talking about them for a long time and the evidence is mounting and mounting that hey, those things might really be black holes, both the stellar sized ones and the supermassive black holes at the centers of galaxies. But real, hard, definitive signatures have been hard to come by." The supernova explosions that lead to black holes and compact neutron stars and pulsars offer equally exciting prospects. One of Chandra's first targets will be the expanding cloud of debris marking the shattered remains of a massive star in the Large Magellanic Cloud that exploded in 1987. "It's thought that all sorts of shocks will start to occur in the next few years when the expanding cloud of debris starts hitting all the other stuff that was thrown off from the outer envelope of the star before it exploded," Tananbaum said. "So we should be doing some kind of assaying of the abundances, the temperature and density and pressure states of a lot of that different material. It should just look like a Christmas tree." As the expanding shock wave from the star's detonation reaches material thrown off earlier, energetic collisions will create heavier elements and generate radiation "that should tell us about the chemical composition of the star before it blew up," Tananbaum said. "There's a chance that with the resolution of Chandra that over the 10-year life, as the material expands, we'll actually be able to just slightly separate any central source, which could be a pulsar or it could be just a cooling neutron star. We may actually be able to see the surface of the neutron star as it's cooling just a few years after the explosion." On a vastly larger scale, Chandra is expected to shed light on the amount of dark matter present in the universe, the as-yet-undetected material thought to make up 90 percent of the cosmos, by studying clusters of galaxies. The galaxies making up such clusters are embedded in huge clouds of hot gas that emit X-rays. Those clouds are held in place by the gravity generated by all the components of the cluster. "The only thing that can really be holding it is gravity," Tananbaum said. "And then you can say to yourself, well, I see the gas itself and it generates a certain amount of gravity. I see the stars and the galaxies, they generate a certain amount of gravity. Is that enough gravity to hold onto the hot gas? The answer is always no by factors of several, even 10 or in some cases, more." Chandra observations will enable astronomers to refine their estimates of how much normal matter is present in a given cluster and thus how much - and possibly, what type - dark matter must be present to generate the gravity needed to hold the cluster together. "It may not be able to tell exclusively what the dark matter is," Tananbaum said. "But we should be able to see how much is there with greater precision by far than we've been able to up to now." Along with opening new vistas in X-ray astronomy, Chandra may even help engineers on Earth by providing insights into the physics of nuclear fusion. "We are now going to do plasma diagnostics on incredible emission mechanisms, all kinds of bizarre things that will help us gain a better understanding of plasma processes because we'll be looking at things under extreme conditions: Supernova shock waves, emissions near the surface of a neutron star where the magnetic fields are high, all of these things," Weisskopf said. "Now all of the sudden, instead of just saying we see the emission, we'll be able to dissect the energy spectrum and really get a handle on the nitty gritty details of the emission mechanisms in a laboratory that you just don't have on Earth. And I've got to believe that's going to have some incredibly profound consequences down the road." The drive to launch an X-ray observatory dates back more than 20 years when NASA planners envisioned building an instrument called the Large Orbiting X-ray Telescope. "It was a one-meter class, arc-second-class X-ray observatory, Weisskopf said. "That got descoped and became the Einstein Observatory. But it was Chandra in another name." The success of the Einstein project prompted NASA to include the Chandra X-ray Observatory in the Great Observatories program. The agency originally planned to launch Chandra into a low-Earth orbit where it would be periodically serviced and upgraded by spacewalking shuttle astronauts over a projected 15-year lifetime. The 32,000-pound telescope was to be equipped with a high-resolution X-ray camera and an imaging spectrometer capable of studying a broad range of high- and low-energy X-ray photons. In addition, the spacecraft included a sensitive liquid helium-cooled X-ray spectrometer. But in 1991, escalating costs and technical complexity forced NASA to reduce the scope of the Chandra mission. "Originally, it was a low-Earth orbit, servicing and replenishment mission like Hubble," Weisskopf said. "In 1992, that was just growing out of control in terms of projected costs. So what one did was to take the first complement of instruments, which was very powerful, and break it up into two missions." One spacecraft, equipped with the high-resolution camera and the imaging X-ray spectrometer, would be launched into a highly elliptical orbit. While the spacecraft would be beyond the reach of shuttle repair crews - saving NASA some billions over the life of the program - it would be able to operate near continuously, taking data over 55 hours of each 64-hour orbit. The other spacecraft, equipped with the super cooled X-ray spectrometer, would be launched into a low-Earth orbit. NASA cancelled the second spacecraft in 1993 in another round of cost cutting. Even so, Chandra remains an expensive proposition: $2.78 billion through the first eight years of operation. That includes $1.55 billion for spacecraft development; $383.9 million for shuttle launch support; $76 million for a Boeing-built Inertial Upper Stage booster to reach the planned orbit; some $92.5 million per year for mission control and data analysis; $3 million per year for use of NASA's data relay satellites; and a one-time charge of $18 million for an X-ray mirror test facility in Alabama. Still, the project is nearly $4 billion cheaper than the originally planned all-in-one low-Earth orbit mission. "The alternative we were looking at was Chandra in this orbit or no Chandra at all," Weisskopf said. "And so we took the risk to reduce the cost because the option scientifically was infinitely better to have an Chandra in orbit as opposed to no Chandra at all. We saved billions of dollars with that decision. You could build another Chandra with that money." The decision to launch the surviving elements of Chandra into an orbit beyond the reach of shuttle repair crews was an especially tough call. The Hubble Space Telescope was launched in 1990 with a flawed primary mirror but it later was repaired by spacewalking astronauts. No such repair will be possible for Chandra. But the telescope's high orbit offers other advantages. "The orbit is a lot more benign in the sense that you're away from the Earth most of the time so you're not cycling from light to dark, warm to cold, every hour and a half," said Tananbaum. "We don't have to deal with the temperature cycling, which tends to wear out both electrical and mechanical components." In addition, the telescope will spend most of its time high above Earth's radiation belts, avoiding interference from energetic particles that otherwise could overwhelm the telescope's ultra-sensitive instruments. "Once it's up there and working, there's reason to be hopeful that it will work for 10 or 15 years anyway in that orbit," Tananbaum said. But, he added, "we've got to get it right the first time." =================================================================== Shuttle crew arrives; countdown begins (07/16/99) 10:45 a.m. Update: Shuttle crew arrives for launch On the 30th anniversary of Apollo 11's launch on the first lunar landing mission, America's first female shuttle commander and her four crewmates flew to the Kennedy Space Center this morning to prepare for blastoff Tuesday to put a $1.6 billion X-ray telescope in orbit. Commander Eileen Collins and company touched down on the shuttle landing strip around 7 a.m. to begin final preparations for launch. "This crew is ready to fly," she said. "We are just so excited about taking up the Chandra X-ray Observatory. The payload's ready, the upper stage booster is ready, the [shuttle] Columbia is ready. This crew has been training so hard, actually over the past year and more. I'm so proud of them and they're going to do a great job on the flight." Columbia's countdown to blastoff is scheduled to begin at 10 p.m. this evening. A stone's throw away from the shuttle firing room, more than 1,000 retired Apollo workers, managers and current NASA and contractor employees will be wrapping up a dinner marking Apollo 11's launch 30 years ago today. Moonwalkers Neil Armstrong and Buzz Aldrin are expected to address the crowd, seated under a restored Saturn 5 moon rocket. Armstrong will participate in a news conference today at 5:30 p.m. that will be carried live on NASA television. The reclusive astronaut seldom grants interviews and media interest in his comments today is high. A few miles away at launch pad 39B, Columbia stands poised for blastoff on the 95th shuttle mission. "We take spaceflight pretty seriously and we've been real busy back in Houston getting ready for this flight," said astronaut Cady Coleman. "Sometimes it's easy to forget we're about to go and do an incredibly wonderful thing. I'll just tell you that climbing into the airplane this morning, packing last night, realizing I'd be back in just a week, just five days, suddenly you start realizing you're about to get on board a space shuttle and be on your way to space. It makes you feel very, very special. I'm pleased to be here and very excited about deploying the Chandra." There are no technical problems of any significance and the preliminary forecast calls for generally good conditions with a 70 percent chance of favorable weather. A detailed mission overview is posted immediately below. 11:30 p.m. Update: Countdown begins for shuttle Columbia The shuttle Columbia's countdown to blastoff on the 95th shuttle mission began on time this evening at 10 p.m., setting the stage for a launch attempt at 12:36 a.m. Tuesday. With no technical problems at pad 39B, forecasters are predicting a 70 percent chance of acceptable weather Tuesday, the 30th anniversary of Apollo 11's landing on the moon. As the countdown was getting underway, moonwalkers Neil Armstrong, Buzz Aldrin and a throng of other astronauts and engineers from the Apollo era were wrapping up a heavily attended dinner party marking the anniversary of the first moon landing. As guests departed, the roar of jet engines could be heard nearby as Eileen Collins, the first woman to command a space shuttle, practiced landing procedures in a NASA business jet modified to handle like a space shuttle on final approach. A few miles away at launch pad 39B, engineers were working through the initial phases of Columbia's countdown and gearing up to pump liquid hydrogen and oxygen aboard the orbiter Saturday to power the ship's three electricity producing fuel cells. This status report will be updated as soon as possible after a countdown briefing at 9 a.m. Saturday or as conditions warrant. =================================================================== NASA managers assess Chandra capacitor issue (07/17/99) With the shuttle Columbia's countdown ticking smoothly toward launch Tuesday, NASA managers and contractors are revisiting an issue involving the reliability of electrical capacitors in the Chandra X-ray telescope's power supply system. Sources say engineers are "cautiously optimistic" the $1.6 billion Chandra will be cleared for launch as is, but a final decision will not be made until after a traditional launch-minus-two-day management review at 2 p.m. Sunday. As of this writing, details are sketchy, but concern about the capacitors first surfaced several weeks ago when the telescope's prime contractor, TRW Space and Electronics Group, discovered cracks in capacitors with a similar pedigree as some 40 capacitors on board Chandra. NASA sources said other capacitors of the same pedigree are on board three other orbiting satellites and no failures have ever occurred. Chandra has had a tough road to the launch pad. The observatory originally was scheduled for launch last August, but the flight was repeatedly delayed, first by work to resolve software problems, then because of concern about delaminating circuit boards. A third delay was ordered with a Boeing-built Inertial Upper Stage booster similar to the one that will be used by Chandra malfunctioned in April during launch of an Air Force Titan 4 rocket, stranding a missile early warning satellite in a useless orbit. Assuming resolution of the capacitor issue, the telescope appears finally ready for flight. Otherwise, the launch team is pressing ahead with Columbia's countdown and gearing up to pump liquid hydrogen and oxygen into the shuttle to power the ship's three electricity producing fuel cells. Final processing of the Chandra X-ray telescope is complete and engineers were scheduled to close the shuttle's cargo bay doors this morning. "We're not working any issues or concerns," NASA test director Doug Lyons said at a morning briefing. "Flight and ground systems are in excellent shape and we're looking forward to a successful launch." Columbia's crew has three shots at getting off the ground - July 20, 21 and 22 - or the flight will be delayed into August. A Boeing Delta 2 rocket is scheduled for launch July 24 and after that, the Air Force Eastern Range, which provides tracking, photo documentation and self-destruct support, will shut down for maintenance between July 26 and Aug. 11. Additional attempts could be made during the following week but after that, launch would slip indefinitely because of required maintenance on Columbia itself. "Again, we hope to successfully launch on the 20th through the 22nd," Lyons said. Once Columbia takes off, NASA plans to launch a radar mapping mission in September and a flight to service the Hubble Space Telescope in mid October. After that, all bets are off because of problems completing and testing major U.S. and Russian space station components. A critical Russian command and propulsion module is scheduled for liftoff aboard a Proton rocket on Nov. 12, followed by launch of a Progress supply craft Nov. 25 and then, on Dec. 2, the space shuttle Atlantis to ferry more supplies and equipment to the station. Another Progress is scheduled for launch Feb. 17, a U.S. truss element will be launched Feb. 24 and the first full-time crew on March 12. After that, a large U.S. solar array component is scheduled for launch and, after a Progress flight April 2, the U.S. laboratory module on April 20. But that schedule may be threatened, sources say, because of problems readying the solar array system and the U.S. lab module. Sources say the arrays could slip to mid May while the lab could be delayed to mid June. If that scenario plays out, and if the Russians do, in fact, launch the service module in November, it's not clear whether the first full-time crew would launch on schedule or even if the December shuttle flight would launch as planned. At present, the launch schedule has not been changed and Atlantis remains on track for launch Dec. 2. But readers should be aware quite a bit of talk is going on about potentially major space station launch slips. =================================================================== NASA clears Columbia, Chandra telescope for Tuesday launch (07/19/99) NASA managers today formally cleared the shuttle Columbia and its crew for launch Tuesday - the 30th anniversary of the Apollo 11 moon landing - to ferry the $1.6 billion Chandra X-ray Observatory into orbit. Shuttle program manager Ron Dittemore said earlier concern about the reliability of critical capacitors in the telescope's electrical system were resolved and the observatory was cleared for flight after a review showed no connection between the capacitors aboard Chandra and one that failed during a recent test. "The very fact that we're here is quite an accomplishment in getting this payload as far as it has come for the last year," Dittemore told reporters at a pre-launch news conference. "We've had some challenges with some software and some hardware problems, but we've finally got to the point where we've completed all our management reviews and we're ready to proceed to launch." If all goes well, commander Eileen Collins - the first woman to command a space shuttle, pilot Jeff Ashby, Cady Coleman, Steve Hawley and Frenchman Michel Tognini will blast off from pad 39B at the Kennedy Space Center at 12:36 a.m. Tuesday. There are no technical problems at the pad and forecasters continue to predict a 70 percent chance of good weather. "We're remaining optimistic the weather won't delay Col. Collins and her crew launching on the 30th anniversary of Apollo 11's historic landing," said Capt. Clif Stargardt, an Air Force meteorologist. Hillary Rodham Clinton is expected to attend the launching, along with members of the world champion U.S. women's soccer team. Collins and company have just three days to get off the ground or the flight will be delayed to mid August because of other upcoming rocket launches and required maintenance on Air Force tracking systems. With forecasters predicting generally good weather Monday, Tuesday and Wednesday, NASA managers are optimistic about getting the 95th shuttle mission underway this week as planned. But they're taking no chances. While they typically make two launch attempts and then stand down a day for rest, the team is prepared to fuel the shuttle for three attempts in a row if necessary, depending on the nature of the problems that prevented a launch the first two days. The issue is critical to NASA because Columbia already is booked to spend a year in California undergoing required inspections and modifications. If the shuttle's arrival in California is delayed past August, Columbia's next flight, a mission to install new instruments aboard the Hubble Space Telescope, also could be delayed. For all of those reasons, Chandra must be off the ground by mid to late August or the observatory will be grounded until late next year. The observatory already is one year behind schedule and NASA managers want to get it into orbit this week if at all possible. "This really is our best opportunity, three days in a row," Dittemore said. "This really is our best shot." Assuming an on-time liftoff, the Hubble-class Chandra will be pushed out of Columbia's cargo bay seven hours and 17 minutes after launch. A two-stage solid-fuel Inertial Upper Stage booster will fire an hour later to propel the telescope to its final orbit. Once that occurs, Chandra will be forever beyond the reach of astronaut repair crews, putting pressure on NASA to get it right the first time. The telescope already is running a year behind schedule because of software problems and work to replace suspect circuit boards. The latest question about Chandra's health cropped up during testing earlier this summer at a vendor in California when a capacitor cracked and caused a power supply to fail. Similar power supplies are on board Chandra. Engineers debated the issue Friday and decided the spacecraft is safe for launch as is. "There was an industry alert put out on a particular type of DC power supply that had a cracked capacitor that led to the failure of that power supply," said payload manager Scott Higginbotham. "There was only one, apparently, that failed and that was out in California at a vendor." Chandra is equipped with 20 different power supplies equipped with capacitors that are similar to the one that prompted the initial alert. "As it turned out, those capacitors that had the alert were a different design and a different manufacturer than those we had on this particular spacecraft," Dittemore said. "We had a number of meetings ... and decided we were good to go." =================================================================== Shuttle launch scrubbed at T-minus seven seconds (07/20/99) 12:00 p.m., 07/19/99, Update: Shuttle Columbia readied for fueling Engineers are readying the shuttle Columbia for fueling late today and blastoff early Tuesday on a showcase mission to launch the $1.6 billion Chandra X-ray Observatory. Forecasters continue to predict a 70 percent chance of acceptable weather during Columbia's 46-minute launch window, giving NASA managers optimism the oft-delayed flight will finally get underway after a year of technical snags and slips. "The Hubble [Space Telescope] revealed the visible side of the universe," said theorist Michael Turner of the University of Chicago. "But most of the universe does not emit visible light. It's only visible by other means, in particular the X-rays. "So Chandra will give us the same clarity of vision as Hubble does, but for the dark side of the universe, which is the bulk of the universe, the side of the universe we know the least about. So the discovery capabilities are immense." Shuttle fueling is scheduled to begin at 3:46 p.m., when engineers working by remote control will start pumping a half-million gallons of liquid oxygen and liquid hydrogen rocket fuel into Columbia's external tank. The procedure should be complete by 6:46 p.m. Columbia's crew - commander Eileen Collins, pilot Jeff Ashby, Cady Coleman, Steve Hawley and Frenchman Michel Tognini - will be awakened at 7 p.m. for breakfast and a final round of weather and countdown briefings before suiting up and heading to pad 39B at 8:51 p.m. Columbia's payload is more than a year behind schedule because of problems with Chandra's computer software, delaminating circuit boards and the recent malfunction of a booster similar to the one that will boost the telescope to its operational orbit. Grant Cates, the engineer in charge of Columbia's ground processing, said the team is thrilled to finally be poised for launch. "Columbia and the entire processing team are very happy to be ready to launch this mission," he said. "We've been on the ground for quite a while." Chandra is the heaviest payload ever launched by a space shuttle. Including its two-stage inertial upper stage booster, the payload and its support equipment tip the scales at 50,162 pounds. Columbia is NASA's oldest - and heaviest - space shuttle but the only orbiter that can carry the 57-foot-long telescope/booster combination in its 60-foot-long cargo bay. To enable Columbia to lift Chandra into space, unneeded equipment was removed and now-outdated but lighter main engines were installed, cutting the shuttle's weight by some 7,000 pounds. "We put Columbia on a strict diet to get to this mission," Cates said. "That work actually began three years ago with the identification of this mission and the weight reduction that would be required." Even so, the shuttle's weight would exceed NASA's normal safety limit in the event of an engine failure prompting an emergency return to the Kennedy Space Center. At touchdown following a return-to-launch-site abort, Columbia and its payload would weigh about 249,300 pounds, some 1,300 pounds above NASA's fleet-wide limit. For Columbia's flight, a one-time waiver was signed based on a detailed analysis of the cargo, the shuttle's center of gravity and a variety of other factors. For her part, Collins, the first female shuttle commander, has no concerns. "In an abort landing, we would land at 205 knots, which is very close to the maximum certification, which is around 214," Collins said. "So there are some challenges there. [But] I feel very confident we've looked at the abort landings and they're well within the safe limits of landing the shuttle." 03:20 a.m., 07/20/99, Update: Shuttle launch scrubbed at last second The shuttle Columbia's launch on the 30th anniversary of the Apollo 11 moon landing was scrubbed at about T-minus seven seconds this morning, a half-second before main engine ignition, delaying Eileen Collins' debut as NASA's first female shuttle commander for 48 hours. As it turns out, the launch team was misled by false indications of high levels of hydrogen in the shuttle's engine compartment. As a result, Collins and her four crewmates will be able to make a second launch attempt at 12:28 a.m. Thursday, after work to refurbish launch pad systems that were activated during this morning's attempt. Columbia's countdown proceeded smoothly throughout the night, with no problems of any significance. Then, at T-minus 16 seconds, one of two hazardous gas detection systems indicated a hydrogen reading of 640 parts per million. The limit is 300 ppm and even though the second hazardous gas system showed normal readings in the 110 to 115 ppm range, the engineer in charge of the system ordered a cutoff at T-minus eight seconds. Within one second, the operator of the firing room's ground launch sequencer computer issued the requested commands, stopping the countdown an instant before main engine ignition. "He called that cutoff at eight seconds prior to T-zero," launch director Ralph Roe told reporters. "As you all know, the engines start at [6.6] seconds. GLS responded to his manual cutoff and the count was terminated just around seven seconds, probably less than a half a second before we would have started the engines." Troubleshooting quickly showed hydrogen levels in the engine compartment were not, in fact, out of limits. NASA mission management team discussed the issue and elected to reschedule Columbia for a second launch attempt Thursday, deciding a 24-hour turnaround would not be feasible. Another launch attempt this week is only possible because Columbia's three main engines, which begin firing up at T-minus 6.6 seconds, never ignited. Had one or more done so, Columbia would have been grounded for three weeks for engine inspections and refurbishment. On-pad engine shutdowns are called redundant set launch sequencer aborts, or RSLS aborts. Five such shutdowns have occurred in shuttle history, the last occurring on Aug. 18, 1994. In any case, if Columbia isn't off the ground by Thursday, the 95th shuttle mission will be delayed to mid August at the earliest because of other upcoming rocket launches and required maintenance that will sideline Air Force tracking systems for two weeks or so. As it is, today's scrub was a frustrating disappointment for Collins and her crewmates - pilot Jeff Ashby, Catherine "Cady" Coleman, Steven Hawley and Frenchman Michel Tognini - who have been training for some 15 months to launch the $1.6 billion Chandra X-ray Observatory. The flight originally was scheduled for last August, but it was repeatedly delayed because of computer software problems, delaminating circuit boards and concern about the recent failure of a booster similar to the one that will boost Chandra into its final orbit. The scrub also was disappointing for thousands of dignitaries, area residents and tourists, including Hillary Rodham Clinton, daughter Chelsea and the U.S. women's soccer team, who all flew to Cape Canaveral aboard a White House aircraft to watch this morning's launch. But Roe and Donald McMonagle, chairman of NASA's mission management team, praised the launch team for putting safety first and stopping the countdown when there was uncertainty about conditions in the aft compartment. "I have no frustration whatsoever," Roe said. "I'm extremely happy with the response of the team and how it reacted. I mean, you don't get any closer to lighting those engines than we did. The team responded extremely well." Said McMonagle: "The response that the team has to a problem is independent to the presence of any high level public appearance people and we're proud of the team's capability to operate without being influenced by that." But the aborted launch was dramatic nonetheless. "T-minus 15 seconds," said launch commentator Bruce Buckingham as Columbia's 12:36 a.m. launch time approached. "T-minus 12... 10, nine..." "GLS [ground launch sequencer] is go..." an engineer said. "GLS, give cutoff!" interjected the hazardous gas detection system controller. "...eight, seven," Buckingham continued. "Cutoff! Give cutoff," said NASA test director Doug Lyons. "Cutoff is given," the GLS engineer quickly replied. "We have hydrogen in the aft," a controller said. "At 640 ppm [parts per million]..." "We have a cutoff of our sequence..." Buckingham said. "...We are decreasing now," the controller reporting the hydrogen excess reported. "NTD, this is CPROP. We see the spike," another controller reported. "OK. Any emergency securing required?" Lyons asked. "Negative, sir, everything's coming down." NASA sources said the initial indication of high levels dropped to a normal 125 ppm within 10 seconds of the scrub, indicating a faulty sensor or telemetry. With Columbia in an obviously safe configuration, Collins and company patiently waited for technicians to return to the pad to assist them getting out of the shuttle. The close-out crew was cleared to return to the pad after engineers in the firing room 4.2 miles away began the process of draining liquid oxygen from Columbia's external fuel tank. The countdown scrub was reminiscent of problems with hydrogen leaks in 1990 that repeatedly delayed Columbia's launch on another astronomy mission. But those leaks were blamed on problems with the 17-inch disconnect system where fuel lines from the external tank enter the engine compartment. =================================================================== Second launch attempt delayed by thunderstorms (07/21-22/99) 11:00 a.m., 07/21/99, Update: Shuttle Columbia set for second launch try Engineers have refurbished the shuttle Columbia's launch pad after Tuesday's dramatic launch abort, setting the stage for a second launch attempt at 12:28 a.m. Thursday to ferry the $1.6 billion Chandra X-ray Observatory into space. If launch is delayed again, shuttle mission STS-93 will slip to mid August because of other rocket launches and planned upgrades to Air Force tracking systems. With forecasters predicting a 100 percent chance of acceptable weather during Columbia's 46-minute launch window, engineers plan to begin pumping another load of liquid oxygen and liquid hydrogen rocket fuel into the shuttle's external tank around 3:16 p.m. The procedure should be complete by 6:16 p.m., weather permitting. Forecasters say thunderstorms could build up in the launch area this afternoon and if lightning is detected within five nautical miles of pad 39B, fueling will be delayed. But Columbia's countdown features four hours and 50 minutes of built-in "hold" time, and as long as tanking begins by 6 p.m. or so, commander Eileen Collins and her four crewmates should be able to take off as planned. Hoping for the best, Collins, pilot Jeff Ashby, Cady Coleman, Steve Hawley and Frenchman Michel Tognini - went to bed around 11 a.m. They will be awakened at 7 p.m. for breakfast and a final round of weather and countdown briefings before suiting up and heading to pad 39B at 8:43 p.m. Tuesday's launch try was scrubbed at T-minus seven seconds, when Ozzie Fish, a United Space Alliance engineer monitoring hazardous gas detection systems, noticed a sudden increase in hydrogen concentrations in Columbia's aft engine compartment. Data were normal until T-minus 16 seconds, when readings from the primary hazardous gas detection system shot from 112 parts per million to 640 ppm. The secondary detection system continued to display normal readings but because it takes eight seconds for the primary display to update, Fish could not wait for a second reading to confirm the presence of a possible leak. By the time it came in at T-minus eight seconds, he would not have had time to order a countdown cutoff before Columbia's three main engines would have started igniting at T-minus 6.6 seconds. The countdown can be aborted after main engine start, but another launch attempt would be delayed three weeks or longer for engine servicing. "We came within milliseconds of starting the engines," Cates said. "Had we started the engines, we wouldn't be here today talking about a launch tonight. We'd be talking about a launch in August. We would have had at least three weeks, probably more, to turn these engines around and go fly this mission." So at T-minus nine seconds, Fish urgently told Barbara Kennedy, the operator of the ground launch sequencer computer, known as GLS, to "give cutoff." In the next second, Kennedy sent the proper command and the countdown stopped about one second after that, at roughly T-minus seven seconds, just a half second or so before the engines would have started firing up. As it turned out, the reading that came in at T-minus eight seconds showed normal hydrogen levels once again. The spike seen at T-minus 16 seconds apparently was caused when the primary detector "burped" a bit of hydrogen back into the sensor tube. This phenomenon happens occasionally but in this case, it happened at the worst possible moment. "It was an incredibly unfortunate coincidence that it occurred at that point where we didn't have time to get another reading before the engines started and it was at a point when the concentration in the aft was already increasing as it normally would," Cates said. "The additional increase looked exactly like a hydrogen leak would look if it was real. "Had this been a real hydrogen leak and he not made that call, we would have made the call after the engines had started and we would have had a shutdown. So it was incredibly good judgment to make that call and make that call as quickly as the team did." For Thursday's launch attempt, the same hazardous gas detection systems will be used. But this time around, Fish will wait for one additional set of readings before ordering a hold, even if that means letting the engines start up on schedule. For his part, Cates said he would be "amazed" if Tuesday's scenario somehow repeated itself. "We are extremely confident at this point that the aft engine compartment is sound, that we don't have a hydrogen leak in there and that we'll have a successful launch tonight," Cates said. But Thursday is the crew's last chance to take off this month. The Air Force Eastern Range, which provides radar tracking, photo documentation and self-destruct control for NASA, commercial and military launches, already is booked Saturday to support a commercial Delta 2 flight. It takes two days to reconfigure the range system to support a different launch, ruling out any chance to launch Columbia on Friday. On July 26, the range will shut down for 18 days of maintenance and upgrades. If Columbia does not get off the ground Thursday, the flight will be delayed to mid August at the earliest. But shuttle managers are optimistic about their chances this evening. 09:10 p.m., 07/21/99, Update: Shuttle crew begins boarding Columbia for second launch try Commander Eileen Collins and her four crewmates began strapping in aboard the shuttle Columbia at 9:10 p.m., bracing for their second launch attempt in 48 hours after a dramatic launch scrub Tuesday at T-minus seven seconds. Columbia's liftoff on the 95th shuttle mission is targeted for 12:28 a.m. Thursday. There are no technical problems at pad 39B and forecasters are predicting a 100 percent chance of good weather during Columbia's 46-minute launch window. 02:45 a.m., 07/22/99, Update: Shuttle Columbia grounded by thunderstorms Unexpected thunderstorms and lightning forced NASA to scrub this morning's planned launch of the shuttle Columbia, delaying the deployment of a $1.6 billion X-ray telescope another 24 hours, to 12:24 a.m. Friday. If Columbia's crew isn't off the ground by Friday, the flight will be delayed to Aug. 18 at the earliest. This morning's scrub was the second delay in 48 hours for Columbia's crew and another blow to astronomers awaiting delivery of the Chandra X-ray Observatory, already running one year behind schedule because of technical snags. "Clearly, the office of space science is disappointed," said Earle Huckins, a senior manager at NASA headquarters. "But when you've waited 20 years to get this X-ray telescope on orbit, an additional day is not something to get particularly concerned about. ... We'll be back again [Friday morning] and hopefully we'll find the third time to be the charm." Program scientist Alan Bunner agreed, saying "of course the science team is disappointed not to get this flight off. We were all very high and up and ready for this tonight. But most important, of course, is to have a safe mission. We want a safe mission and we don't want to violate launch constraints." The forecast for Friday calls for a 70 percent chance of acceptable weather during Columbia's launch window. The countdown had proceeded smoothly throughout the night Wednesday with no technical problems of any significance. But a sudden thunderstorm swelled up north of Cape Canaveral and moved into the launch zone as the countdown entered its final stages. Because of lightning and high electrical activity near the launch pad, the countdown went into an extended "hold" at T-minus five minutes. Columbia's launch window originally was set at 46 minutes based on communications and solar power requirements for activating and checking out the Chandra X-ray Observatory. Hoping the weather would clear, the window was extended, a move that would have forced the astronauts to delay releasing the satellite into open space by 24 hours. But it was not to be. "Due to the storm that's slowly moving to the south, we need to scrub for the day," launch director Ralph Roe said at 1:18 a.m., 50 minutes after Columbia's original launch time. "OK, copy that," said NASA test director Doug Lyons. "No go due to weather." Roe then passed the news along to Eileen Collins, NASA's first female shuttle commander. "Eileen, we gave it our best shot with this storm today, but it didn't agree with us so our best bet is to give it another try another day," Roe said. "OK, CDR copies," Collins replied. "And we thought you guys did just a great job tonight. We're proud of the work and the crew will be ready to go at the next opportunity." NASA initially said Columbia had to get off the ground this morning or the flight would be delayed to mid August because of conflicts with a Delta 2 rocket launch set for Saturday and already planned work to upgrade Air Force tracking systems used to support all east coast launches. But the Air Force agreed to delay the start of the upgrade work if necessary, Delta-builder Boeing and its customer, Globalstar, agreed to delay their launch from Saturday to Sunday and NASA was cleared to make a third attempt to launch Columbia early Friday. "The program has worked with Delta and given us the opportunity for a 24-hour scrub," Roe told the launch team. "So we'll try again in another day." Columbia's launch window will be extended to 90 minutes Friday. The plan will be to deploy Chandra as originally planned seven hours and 17 minutes after liftoff during the shuttle's sixth orbit. But if launch is delayed past the original 46-minute window, the telescope's deployment in space will be delayed to ensure proper solar power and to improve communications. But Friday is Columbia's last chance this month. The next available launch date is Aug. 18, after the Air Force range upgrades are complete and after another Delta 2 launch earlier next month. Already running a year behind schedule, today's launch slip no doubt was frustrating for Columbia's crew. Flight engineer Steven Hawley, who has weathered more launch delays than any of his crewmates, arrived at pad 39B Wednesday night wearing a paper bag on his head in a joking attempt to keep Columbia from knowing he was aboard. It didn't work. Looking on were Hillary Rodham Clinton, daughter Chelsea, members of the U.S. women's soccer team and thousands of other dignitaries, tourists and area residents who were disappointed Tuesday morning when Columbia's countdown was stopped at the T-minus seven-second mark. The dramatic last-second abort was caused by readings indicating a leak in Columbia's engine compartment. As it turned out, the readings were false and Columbia was good to go all along. But it took 48 hours to refurbish the launch pad and ready the shuttle for a second launch attempt. This time around, there were no technical glitches or any other problems other than the weather. The Chandra X-ray Observatory, built by TRW Space and Electronics Group, is the third in a series of four planned "Great Observatories" intended to study the universe across the entire electromagnetic spectrum. "It will study the most extreme conditions in the universe: The near environment of black holes, the most powerful, continuous sources of energy in space, known as quasars, and it will test the laws of physics under conditions that are impossible to duplicate on Earth," said Edward Weiler, NASA's associate administrator for space science. "Chandra will answer many long-standing questions about the high energy universe," he said. "But if it's truly successful, it will enable us to pose questions we cannot even dream of today. And that's what the adventure of science is really all about." The Hubble Space Telescope and the Compton Gamma Ray Observatory already are in orbit studying visible light, the near ultraviolet and energetic gamma rays. Chandra is designed to study X rays while the fourth spacecraft in the series will study infrared radiation. But unlike Hubble and Compton, Chandra cannot be repaired if anything goes wrong after release from Columbia. To save money, the telescope was designed to operate in an elliptical orbit with a high point, or apogee, of 87,000 miles and a low point, or perigee, of 6,000 miles, well above the shuttle's maximum altitude. "When I was a kid growing up in Kansas, I had a small telescope in the backyard," Hawley said. "And when I became a professional astronomer I had an opportunity to use some of the major telescopes in the United States, including the 200-inch at Mount Palomar. "And the difference between what you could have in your backyard and something like the 200-inch telescope at Mount Palomar really represents the order of magnitude increase in capability that Chandra will provide over what's currently available in the X-ray region." 08:00 a.m., 09/22/99, Update: NASA managers mull launch options NASA's mission management team will be briefed at noon today on launch window scenarios governing Columbia's third launch attempt at 12:24 a.m. Friday. One leading scenario calls for extending the shuttle's 46-minute launch window by 71 minutes to provide additional time to cope with bad weather or any technical problems that might crop up. That would require waking the shuttle's crew a half-hour later and eliminating 30 minutes of a 40-minute hold at the T-minus nine-minute mark in the countdown. That would avoid violating a rule that forbids keeping astronauts awake for more than 18 hours on the first day of a mission (including countdown hold time). In any case, launch of the Chandra X-ray Observatory would remain scheduled for seven hours and 17 minutes after launch. =================================================================== Shuttle rockets into orbit; crew launches space telescope (07/22-23/99) 09:30 p.m., 07/22/99, Update: Shuttle astronauts strap in for third launch attempt Commander Eileen Collins and her four crewmates suited up and strapped in aboard the shuttle Columbia this evening for a third launch attempt at 12:24 a.m. to ferry a $1.6 billion X-ray telescope into space. Forecasters are predicting an 80 percent chance of acceptable weather, saying the air over central Florida appears more stable than earlier today when thunderstorms grounded Columbia at the T-minus five-minute mark. This will be Columbia's third and final launch opportunity this month. If the shuttle doesn't get off the ground Friday, launch will be delayed to at least Aug. 18, after other upcoming rocket launches and completion of long-scheduled work to upgrade Air Force tracking systems. But Collins, the first woman ever named to command a space shuttle, said her crew - pilot Jeffrey Ashby, Catherine "Cady" Coleman, Steven Hawley and Frenchman Michel Tognini - would be ready whenever Columbia is finally cleared for flight. "We thought you guys did just a great job tonight," she told launch director Ralph Roe early today, after Columbia's countdown was halted at 1:18 a.m. "The crew will be ready to go at the next opportunity." To improve the odds of a successful launch this time around, Columbia's launch window was extended from 46 minutes to 116 minutes, giving the crew a chance to take off anytime between 12:24 a.m. and 2:20 a.m. To avoid violating a rule forbidding astronauts from staying up longer than 18 hours their first day in space, Collins and company were allowed to sleep an extra 30 minutes and a 40-minute hold at the T-minus nine-minute mark was shortened to 10 minutes. Here is the revised countdown: TIME.........EVENT 07:18 p.m....The crew is awakened 07:48 p.m....The astronauts eat breakfast 08:29 p.m....The crew attends a final weather briefing 08:39 p.m....The astronauts begin donning pressure suits 09:04 p.m....The countdown resumes 09:09 p.m....The astronauts depart crew quarters 09:39 p.m....The crew begins strapping in aboard Columbia 10:54 p.m....The shuttle's hatch is closed and latched 11:44 p.m....A 10-minute hold begins at the T-minus 20-minute mark 11:54 p.m....The countdown resumes 12:05 a.m....A 10-minute hold begins at the T-minus nine-minute mark 12:15 a.m....The countdown resumes 12:24 a.m....The launch window opens 02:20 a.m....The launch window closes The goal of the 95th shuttle flight is to deploy the Hubble-class Chandra X-ray Observatory, the most powerful X-ray telescope ever built. It is the third of four so-called "great observatories" designed to study the universe across the entire electromagnetic spectrum. Scientists expect Chandra to spark nothing less than a revolution in astrophysics, studying the death throes of matter sucked into black holes, the inner workings of enigmatic quasars and the debris blown into space by exploding stars. It also may shed light on how much dark matter is present in the universe by better characterizing the amount of normal matter in clusters of galaxies. The flight plan calls for Chandra to be released from its cradle in Columbia's cargo bay seven hours and 17 minutes after liftoff. One hour later, the telescope's two-stage solid-fuel booster is programmed to ignite, beginning Chandra's 10-day trip to an unusual orbit with a high point of 87,000 miles and a low point of 6,000 miles. From that vantage point, Chandra will be able to operate without interference from Earth's radiation belts, making nearly continuous observations of high priority targets. Anticipation is especially high because the mission is running a full year behind schedule. Launch originally was planned for last August. But the flight was held up by software problems with the telescope, work to replace delaminating circuit boards and the failure of an Air Force booster in April that is similar to the rocket that will boost Chandra to its operational orbit. For their part, Collins and her crewmate have been training for this four-day mission for nearly 17 months. And it appeared the astronauts' long wait was finally over Tuesday morning, when the countdown moved inside of 10 seconds to launch. But readings indicating high levels of hydrogen gas in Columbia's engine compartment prompted an abort at T-minus seven seconds. As it turned out, the readings were erroneous and the countdown was recycled for a second attempt Thursday morning. There were no technical problems this time around and Hawley, a shuttle veteran who has endured more launch delays than any other active astronaut, showed up at the pad wearing a paper bag over his head in a joking attempt to keep Columbia from knowing he was on board. It didn't work. As the countdown entered its final stages, an unexpected thunderstorm suddenly developed, forcing NASA managers to hold the countdown at T-minus five minutes. Trying to better the odds, controllers extended Columbia's launch window by 10 minutes in hopes the storm would move out of the area. But it was not to be. While disappointed, Chandra scientists took the delay in stride. "When you've waited 20 years to get this X-ray telescope on orbit, an additional day is not something to get particularly concerned about," said Earle Huckins, a senior scientist at NASA headquarters in Washington. 05:30 a.m., 07/23/99, Update: Shuttle Columbia rockets into orbit; telescope readied for deployment Thirty years after Neil Armstrong's "one small step" on the moon, Air Force Col. Eileen Collins took another giant leap Friday morning, rocketing into history as the first woman to command a space shuttle. Blasting off on their third attempt after launch delays Tuesday and Thursday, the astronauts spent the morning activating and testing the $1.6 billion Chandra X-ray Observatory and its attached inertial upper stage booster, a powerful two-stage rocket that will propel the telescope to its final orbit. Initial checkout went smoothly and if all goes well, astronauts Catherine "Cady" Coleman and French flier Michel Tognini will launch Chandra at 7:48 a.m. EDT to accomplish the primary goal of the 95th shuttle mission. One hour later, the two stages of the telescope's solid-fuel rocket are scheduled to fire in quick succession, boosting the satellite into an orbit with a high point, or apogee, of 46,000 miles and a low point, or perigee, of about 203 miles. Subsequent firings of an on-board rocket system over the next 10 days are designed to raise the high point of the orbit to 87,000 miles and the low point to 6,000 miles, allowing Chandra to operate without interferrence from Earth's radiation belts. The first test images are expected in about three weeks with routine science observations beginning later this year. To avoid damaging the sensitive telescope, Columbia's high-power KU-band television antenna was not immediately activated and no live video of Chandra's release from Columbia was expected. But videotape playback from recorders on board the shuttle was scheduled for around 9:21 a.m., 10 minutes before Chandra's two solar arrays finish unfolding in another critical mission milestone. Built by TRW Space and Electronics Group, Chandra is the third in a series of four planned "Great Observatories" intended to study the universe across the entire electromagnetic spectrum. The Hubble Space Telescope and the Compton Gamma Ray Observatory already are in orbit studying visible light, the near ultraviolet and energetic gamma rays. Chandra is designed to study X rays while the fourth spacecraft in the series will study infrared radiation. But unlike Hubble and Compton, Chandra cannot be repaired if anything goes wrong after release from Columbia. To save money, the telescope was designed to operate in an elliptical orbit well above the shuttle's maximum altitude. "It will study the most extreme conditions in the universe: The near environment of black holes, the most powerful, continuous sources of energy in space, known as quasars, and it will test the laws of physics under conditions that are impossible to duplicate on Earth," said Edward Weiler, NASA's associate administrator for space science. "Chandra will answer many long-standing questions about the high energy universe," he said. "But if it's truly successful, it will enable us to pose questions we cannot even dream of today. And that's what the adventure of science is really all about." The adventure began at 12:31 a.m. when Columbia roared to life and thundered away from the Kennedy Space Center, lighting up the night sky for hundreds of miles around. "We have booster ignition and liftoff of Columbia, reaching new heights for women and X-ray astronomy," said NASA launch commentator Lisa Malone as Columbia started its long-awaited voyage. Shattering the nighttime calm, the veteran space shuttle shot straight up for 10 seconds, rolled about its vertical axis and arced east over the Atlantic Ocean trailing a 600-foot tongue of white-hot fire from its twin solid-fuel boosters. Collins reported an electrical glitch seconds after liftoff and control computers mounted on two of Columbia's three main engines lost power for the duration of the ascent. But each engine is equipped with two controllers for redundancy and all three powerplants operated flawlessly. Flight controllers in Houston later concluded a short circuit aboard the shuttle triggered the original alarm. It was not immediately clear what caused the short, but mission managers said they did not expect it to cause any additional trouble. In any case, eight-and-a-half minutes after liftoff, NASA's oldest space shuttle slipped into a slightly lower-than-planned orbit, kicking off a busy day of make-or-break work to launch Chandra atop its two-stage solid-fuel booster. "It's great to be back in zero G again!" Collins radioed when Columbia's main engines shut down and the astronauts began floating in their seats. While the shuttle reached a safe orbit, its external fuel tank apparently was loaded with 4,000 pounds less liquid oxygen than expected. As a result, Columbia's main engines ran out of oxygen sooner than expected, putting the shuttle in an initial orbit with a low point seven miles below what flight controllers expected. But there was no impact to the mission because, as luck would have it, the telescope's deployment time coincided with the high point of Columbia's orbit and no additional rocket firings were needed to make up the initial shortfall. The successful shuttle launching gave astronomers a shot in the arm after two launch scrubs Tuesday and Thursday and a series of technical problems with the Chandra X-ray Observatory that combined to delay the mission for nearly a year. But this time around, the weather cooperated and, after a seven-minute delay to resolve a communications snag, Chandra's oft-delayed voyage of discovery finally got underway, opening a new chapter in space exploration. "Thirty years ago, we had the first humans walk on the moon and now we're launching an observatory that's going to give us further sight into the universe in a wavelength we've never seen before," said Donald McMonagle, chairman of NASA's mission management team. "In terms of 'giant leaps,' I think we just made one." Collins' role as the first female shuttle commander also might qualify for "giant leap" status. Married to a commercial airline pilot, Collins is a former Air Force test pilot, Air Force Academy math instructor and mother of a three-year-old girl. She is the first female space commander since Soviet cosmonaut Valentina Tereshkova took off in 1963 in the single-seat Vostok 6 capsule and the first with any real responsibility. "What I'm focused on is making sure we make this mission the most successful mission it can be," Collins said before launch. "Whether your commander is a man or a woman doesn't really matter when it comes to getting the mission done." Tereshkova was little more than a passenger during her pioneering mission, but Collins is responsible for one of the most expensive satellites ever launched by NASA and one of the most scientifically promising. 08:00 a.m. Update: Chandra X-ray Observatory Launched With NASA's first female shuttle commander at the helm, the Columbia astronauts launched a $1.6 billion X-ray telescope today to probe the warped space around black holes, the inner workings of galaxy eating quasars and the cosmic building blocks blown into space by exploding suns. Once on station, the Chandra X-ray Observatory, the most sophisticated X-ray telescope ever built, also will study radiation from vast clouds of million-degree gas permeating clusters of galaxies to help refine estimates of how much matter is present. In so doing, Chandra may help astronomers indirectly answer one of the most perplexing questions in astrophysics: How much so-called "dark matter" is present in the universe and whether the expansion of the cosmos will continue forever or ultimately be halted or even reversed. With French astronaut Michel Tognini assisting every step of the way, astronaut Catherine "Cady" Coleman launched Chandra from its cradle in Columbia's cargo bay on time at 7:47 a.m. to accomplish the primary goal of the 95th shuttle mission. "Houston, we have a good deploy," commander Eileen Collins radioed mission control as Chandra and its attached rocket booster slowly drifted away. "Roger, good deploy, thanks for the words, Eileen," replied astronaut Robert Curbeam from Houston. "Chandra is on its way to open the eyes of X-ray astronomy to the world," Collins concluded. A few minutes later, Coleman had to be gently reminded to complete her post-deploy checklist, saying "this telescope was so beautful as it departed, we just could do nothing but take pictures and look at it." The launching came seven hours and 17 minutes after liftoff following a detailed checkout to make sure the observatory's systems were operating normally. Unlike its sister craft, the Hubble Space Telescope, Chandra is bound for an unusual elliptical orbit beyond the reach of shuttle repair crews. To get there, the telescope was equipped with a two-stage Boeing-built rocket called an inertial upper stage, or IUS. Both stages of the $76 million solid-fuel IUS were scheduled to fire in quick succession one hour after release from the space shuttle to begin boosting the satellite toward its operational orbit. "From everyone here in Houston and also the IUS and Chandra teams, we'd like to congratulate you on the flawless deploy and say thanks for deploying the third of NASA's great observatories in orbit," Curbeam radioed. "Well as you can imagine, Houston, we've very excited up here and we're real happy to be part of this team. We'll be following the events to follow, with the IUS burns, the Chandra burns and all the activities that will be taking place over the next several days. We'll be looking forward to hearing from you." This status report will be updated after the upcoming rocket firings. 09:10 a.m. Update: Rocket booster fires to boost telescope toward final orbit Both stages of a Boeing-built inertial upper stage rocket - IUS - successfully fired this morning, boosting the $1.6 billion Chandra X-ray Observatory toward its operational orbit in a major milestone for the long-awaited mission. The first stage of the solid-fuel IUS ignited one hour after the satellite's launch from Columbia, consuming 19,621 pounds of propellant in two minutes and five seconds. Roughly one minute after burnout, stage one was jettisoned and stage two ignited, burning 6,016 pounds of fuel in one minute 57 seconds. The two rocket firings put Chandra in an elliptical orbit with a high point of about 46,000 miles and a low point of some 203 miles. Subsequent firings of the observatory's liquid-fueled maneuvering jets are designed to put the spacecraft in its final operational orbit with a high point of 87,000 miles and a low point of 6,000 miles. "It looks like your satellite is in the proper orbit and ready to start its mission," astronaut Robert Curbeam radioed from Houston. "Well, there are five huge smiles on board here, Beamer," Columbia astronaut Catherine "Cady"k Coleman replied amid cheers from her crewmates. "There are a number of people who have worked many, many years for this moment. It's very exciting that Chandra is on its way. What's most exciting is we have absolutely no idea what it's going to see. I think we're going to find out some new things we didn't even know we had questions about. We're glad to be a part of that." Today's rocket firing was the first for an IUS booster since a similar rocket malfunctioned during an Air Force Titan 4 mission in April, stranding a missile early warning satellite in a useless orbit. The results of an Air Force failure investigation have not been released, but NASA managers participated in the probe and said they took the proper steps to ensure a safe flight for Chandra. Even so, poor communications between the satellite and ground stations delayed confirmation of a successful firing until after 9 a.m. But when the data finally came in through a tracking station in the Indian Ocean, the news was good. "Flight controllers in Sunnyvale, California, reading data now through the Diego Garcia tracking station, report two good burns of the inertial upper stage and that the Chandra X-ray Observatory is in the solar array deploy attitude," reported NASA commentator Rob Navias. 12:25 p.m. Update: Satellite managers thrilled with initial results Engineers at the Chandra Operations Control Center in Cambridge, Mass., are busy this afternoon testing the $1.6 billion Chandra X-ray Observatory's systems and gearing up for a series of critical rocket firings to complete the telescope's trip to its final orbit. So far, no problems of any significance have been noted and project officials are ecstatic with the observatory's performance since launch earlier today from the shuttle Columbia. "We've had no anomalies on any of our systems," said Jean Olivier, Chandra deputy program manger. "Solar arrays are deployed, the system is performing, from a power standpoint, as we'd expect and quite frankly, I don't really know what else to say other than we're completely tickled to death to be here. "It was very difficult as this mission unfolded to keep a straight face and keep from grinning as this thing started to just unfold as a perfect mission," he said. "We thought at any minute something was bound to happen to burst our bubble, but it hasn't yet. At this point in time, we're working with a very good mission, a very good Chandra, and we're expecting ... for it to continue that way." Chandra's two-stage inertial upper stage booster increased the telescope's velocity by 9,000 feet per second - 6,100 mph - and placed the spacecraft in an intermediate orbit with a low point of 204 miles and a high point of 44,839 miles, according to NASA flight controllers. The high point, or apogee, was about 1,000 miles below pre-flight predictions, but that was not believed to be a problem. "This is an absolutely tremendous day for science," said Roger Brissenden, manager of the Chandra Operations Control Center. "We're absolutely thrilled." Engineers spent the afternoon monitoring the telescope and activating its internal liquid-fueled propulsion system in preparation for the first of five critical rocket firings to boost the spacecraft into its final orbit. If all goes well, the apogee will be raised to around 87,000 miles - one third of the way to the moon - while the low point, or perigee, will be increased to around 6,000 miles. The first such rocket firing is planned for 10:23 p.m. Saturday. "We are just ecstatic," said Craig Staresinich, a senior project manager with Chandra's builder, TRW Space and Communications Group. "You couldn't ask for anything better than what we got today. The whole team ... has been practicing what we went through today time after time after time. Most of those practices and simulations were done with contingencies put in them to get us ready for the worst. We always prepare for the worst and hope for the best and we got what we hoped for today. It's the best. It was absolutely flawless." Earlier today, the astronauts downlinked video shot out of the shuttle Columbia's overhead cockpit window as the orbiter blasted off from the Kennedy Space Center. The video was dark and difficult to make out, prompting pilot Jeffrey Ashby to provide a verbal description. "That was one heck of a ride up hill," he radioed Houston. "I was just pretty much hanging on the whole eight minutes going up hill and trying not to yell at the top of my lungs like I was on some roller coaster." =================================================================== Short circuit no problem for re-entry, NASA says (07/24/99) NASA engineers have not yet found a relationship between a short circuit during the shuttle Columbia's launch Friday that knocked two main engine computers out of action, a 4,000-pound loss of propellant and an engine that was running 100 degrees hotter than expected. But they believe the dramatic half-second short circuit likely was triggered by a problem in the orbiter's now dormant main propulsion system. The shuttle's three main engines are not used during orbital operations or re-entry and landing, giving NASA managers confidence whatever went wrong Friday won't have any impact on the remainder of Columbia's flight. "Whatever caused this short is gone and that's probably because wherever the short was it opened up and there is now no potential for current to flow in that area," said Randy Stone, a mission operations manager at the Johnson Space Center in Houston. "Currently, we think it's something in the aft end of the vehicle and doesn't appear to be tied to anything we're operating on orbit." But he said engineers will have to pin down the cause of the short before the next shuttle launch in mid September. "Clearly, we must understand that before we fly again," he said. "But we believe the analysis will be able to do that." The 13.3-amp short circuit five seconds after liftoff provided a scare for reporters, at least, causing two main engine control computers - one on engine No. 3 and one on engine No. 1 - to shut down for the duration of Columbia's climb to orbit. Each of the three main engines is equipped with two control computers, which draw power from independent circuits. Only one computer is required for engine operation after launch and the backup controllers on engines 1 and 3 continued to operate normally as did both engines. Had either engine lost its second controller, however, the powerplant would have shut down and Columbia's crew could have been forced to attempt a risky emergency landing. "If we had taken an electrical hit on another bus, it could have possibly failed an engine, which could have put us on a return to the Kennedy Space Center, or a trans-Atlantic abort to Africa or possibly, if the failure happened later in the ascent, we could have made it to orbit but possibly to a lower orbit," commander Eileen Collins told a reporter earlier today. "So we were looking at our performance boundaries all the way up." While the engines operated normally throughout Columbia's climb to space, they ran out of liquid oxygen propellant slightly early, prompting on-board computers to shut the powerplants down ahead of schedule. That left Columbia with a velocity that was 15 feet per second - about 10 mph - lower than expected, reducing the shuttle's initial altitude by seven miles. It was as if Columbia had been launched with 4,000 pounds less liquid oxygen than required. But Stone said analysis of fueling data indicates Columbia took off with the right amount of liquid oxygen and liquid hydrogen rocket fuel in its external tank. "All the programs we use to compute the amount of propellant that was on board, the density of the propellant, the temperature of the propellant, all those computations appear to be normal," he said. "We believe we had the right load in the tank." If that turns out to be the case, it's not clear what might account for the missing 4,000 pounds of oxygen. A former astronaut speculated that a slight guidance error possibly could result in a 15-foot-per-second "underspeed," or perhaps an improper hydrogen-oxygen mixture ratio in one or more main engines. For his part, Stone was reluctant to speculate until data analysis is complete. "The mixture ratio could have changed on the engines, there are several things that could have caused that to happen," he said. "A mixture ratio shift in one of the engines could cause this kind of shortfall." NASA currently is upgrading its shuttle main engines to improve safety and reliability. The upgraded engines are slightly heavier than the "phase two" powerplants they are replacing. But the X-ray satellite launched aboard Columbia Friday was the heaviest payload ever carried by a shuttle and Columbia was equipped with three phase two engines. As it turns out, engine No. 3, one of the two that lost a controller during launch, ran about 100 degrees hotter than it did during a pre-launch test firing before installation in Columbia, a source said. Whether that is related to the other issues is not yet known. But Stone said engineers will look into the possibility. "Certainly, because we had the electrical problem and the controller problem, any correlation between that and this engine performance will be on our fault tree," he said. A reliable source said engineers suspect the short circuit was triggered by a problem in one of two controllers in question. Stone would not go that far, saying only that "since it was very localized in its effect, it could be a short in the main engine controller itself, but that is just complete speculation." "What we are looking at is all the events, all the switching of hardware, all the valve movements that were taking place during that time and trying to tie an activity or a piece of hardware changing state to this short," he explained. "To date, we have been unable to make any of those connections." Collins, the first woman to command a space shuttle, said today the glitches Friday seemed like just another training run to her and her crewmates. "For the past nine years of my life as I've been training with NASA, we've practiced ascents in the simulator and we're always having malfunctions thrown at us by our devious instructor team," Collins told a reporter this morning. "They like to fail engines on us and make electrical buses short out. "We actually got to practice some of that because we think we had an electrical short on one of our buses [main circuits], but it was a transient. We just saw a momentary light flash and there was nothing else other than the call from Houston that we had lost some redundancy in our main engine controllers. Everything worked fine all the way up to orbit." In the meantime, "the short on AC1 Phase A is currently unexplained," flight controllers said in a morning message to the astronauts. "There has been no observable loss of functionality beyond the SSME [main engine] controllers and there are no restrictions on the usage of AC1 Phase A. The entire community is evaluating the situation. Fault trees of failure modes and effects are expected to be developed by Saturday morning, along with possible causes of the short." The bottom line, controllers punned: "No current impact." Collins and company spent the day working through a battery of on-board experiments. Astronaut Steven Hawley, an astronomer who launched the Hubble Space Telescope and who has experience operating the 200-inch Hale telescope at Mount Palomar, spent several hours operating a seven-inch telescope mounted in Columbia's side hatch window. The Southwest Ultraviolet Imaging System, making its second shuttle flight, can be aimed at targets in the inner solar system that are much closer to the sun than those Hubble is allowed to image. During its first flight, the SWUIS system took more than 400,000 images of comet Hale-Bopp after Hubble had lost it in the glare of the sun. Collins, meanwhile, carried out a series of rocket firings Friday evening to test a complex maneuver planned for a September flight. On that mission, a 200-foot boom will be extended from the shuttle Endeavour's cargo bay as part of a radar mapping system. To avoid flexing the slender boom during required shuttle maneuvers, flight controllers developed a so-called "flycast" procedure in which carefully timed rocket firings act to damp out any flexing while still accomplishing the desired maneuver. =================================================================== X-ray telescope carries out successful rocket firing (07/24/99) Two small engines in the $1.6 billion Chandra X-ray Observatory's on-board propulsion system fired tonight for five minutes, successfully raising the low point of the telescope's orbit some 550 miles in the first of five critical rocket firings. One hour after release from the costly shuttle Columbia on Friday, a two-stage solid-fuel rocket boosted the X-ray telescope into an intermediate transfer orbit with a low point of 204 miles and a high point of 44,779 miles. Tonight's rocket firing at 9:11 p.m. raised the low point of the orbit to 746 miles while lowering the high point slightly to 44,753 miles. Four more rocket firings Sunday, July 29, July 31 and Aug. 2 are required to put the spacecraft in its operational orbit, a huge ellipse with a low point, or perigee, of some 6,200 miles and a high point, or apogee, of about 87,000 miles - one third of the way to the moon. The goal is to maximize the amount of time Chandra spends above an altitude of 37,282 miles. Below that, Earth's radiation belts can affect the performance of the telescope's sensitive instruments. In its planned operational orbit, Chandra will spend 70 to 80 percent of its time above 37,282 miles where it can make uninterrupted observations of deep space targets. Deputy project manager Jean Olivier said earlier today that if the IPS system failed to operate at all, Chandra could still conduct science operations in its current transfer orbit. "We would have a pretty significant fraction of the orbit that we could conduct science in," he said. "[But] nothing near the 70 to 80 percent we'd have in our nominal orbit. The main disadvantage would be the amount of radiation our solar arrays would encounter during the perigee [low altitude] passes. Although we don't have precise data on that, we feel that could begin to limit the lifetime of the mission." But no such problems were expected and mission managers were elated at their initial success activating and checking out the telescope's complex systems. "We have trained for this mission so hard and so long, I was absolutely amazed yesterday," said astronaut Catherine "Cady" Coleman, who flipped the switch that sent Chandra on its way. "Every procedure we did, the results were nominal, everything was just as we expected. "And in our simulations, which we have done many, many times, everything breaks, nothing is nominal," she said. "We're really trained to handle those problems and I just tried to concentrate on doing what I was trained to do, doing what I knew how to do, and I think we were all really excited that it worked out so well." Earlier Saturday, flight controllers staged a practice rocket firing to make sure the correct procedures were in place before carrying out the actual five-minute maneuver. "We had a number of options for burn durations," said Olivier. "Realizing this was the first attempt to use the integral propulsion system, we felt is was appropriate to pick as short a burn as we practically could in order to guard against any unforseen problems. We felt the safety of the mission would be better served to go into this thing rather cautiously and go with a first burn being relatively short." =================================================================== NASA assesses threat of possible main engine nozzle leak (07/25/99) The nozzle of a main engine aboard the shuttle Columbia appears to have developed a potentially dangerous leak during launch Friday, spewing hydrogen rocket fuel into the exhaust plume and forcing the powerplant to run hotter than normal while gulping 4,000 pounds more liquid oxygen than its two counterparts, NASA managers said today. While not yet confirmed, a leak in the nozzle of main engine No. 3 would explain why Columbia's three main engines shut down a split second earlier than planned, leaving the spacecraft seven miles lower and going 10 mph slower than expected. The presumably leaking engine apparently consumed additional oxygen to compensate for the lost hydrogen, effectively running the oxygen tank dry. Engineers already knew 4,000 pounds of liquid oxygen was unaccounted for and that Columbia reached orbit going 15 feet per second slower than expected. Wayne Hale, a senior flight director at the Johnson Space Center, said today a small nozzle leak could prompt an engine control computer to "compensate for that by trying to provide some more thrust, which uses a little bit more oxygen and that could provide a shortage in the liquid oxygen." Main engine No. 3 did, in fact, run slightly hotter than normal during ascent, which one would expect if the engine was trying to make up for leaking hydrogen. And the presumed leak is clearly visible in launch-day video showing closeups of the main engines. In the otherwise nearly transparent plume of engine No. 3's exhaust, a brilliant white streak is present, presumably a short stream of burning hydrogen. But Hale said Columbia's crew was never in any danger of an engine shutdown or a catastrophic failure, saying "we don't think this is a case that even approaches that." He said the leak apparently started seconds after main engine ignition. It was unrelated to a short circuit that occurred five seconds after liftoff that knocked two engine control computers out of action for the duration of Columbia's ascent. The cause of the 13-amp short in one of the shuttle's three AC circuits, or buses, was a mystery until today, when commander Eileen Collins took a second look at one of Columbia's fuse boxes. While she didn't notice anything unusual Friday, a closer look today showed one of main engine No. 1's breakers had, in fact, popped out. Engineers now believe the short occurred in one of main engine No. 1's two engine control computers or in the wiring between it and the cockpit. All three main engines are equipped with two controllers powered by independent circuits. The short knocked out one controller on engines No. 1 and 3, but the rest, powered by different circuits, continued operating normally to keep all three engines running. Columbia's slightly low initial altitude had no impact on the crew's primary payload, the $1.6 billion Chandra X-ray Observatory. The Hubble-class telescope was deployed into the correct orbit later that day. And the issue is no concern for Columbia's return to Earth Tuesday because the three main engines are only used during launch. The short circuit would not appear to have any significant long-range impact now that engineers have a better idea where it was located. But a leak in an engine nozzle, if confirmed, would represent a significant issue and one that could force delays for downstream flights. "It's way, way too early to talk about what the implications are," Hale said. "It could be very simple and could be a really quick fix or it could be something that would take a little longer." Shuttle main engine nozzles are made up of more than 1,000 small tubes welded together to form a cone. Part of the hydrogen fuel routed to each engine is diverted to flow through the nozzle tubes to provide cooling. The escaping hydrogen from one or more tubes in main engine No. 3's nozzle is clearly visible on videotape closeups as a brilliant white plume in the otherwise transparent exhaust. Hale said the apparent leak is consistent with tears or split seams in one or two of the quarter-inch-wide tubes, which would result in the loss of about 2,500 pounds of hydrogen fuel. "We're talking in the range of three or four, maybe five, pounds of hydrogen per second, which is not a lot of flow," he said. "That's about two, at most, of these tubes if they were to dump their entire flow into the nozzle instead of being recirculated. "We have found a couple of cases post flight when we got the engines back and inspected them, we have found some nozzle tube leaks that were small enough that they were not detected in flight," he said. "So we've had this kind of occurrence before." Earlier nozzle leaks were traced to weaknesses caused by corrosion. NASA changed its nozzle processing techniques a few years ago and engineers believed the problem had been resolved. In any case, Hale said the crew was in no danger of a catastrophic failure because before a propagating leak could get out of hand, an engine's controller would shut the powerplant down. That could trigger an abort and an emergency landing in Florida or Africa, depending on when the shut down occurred, but not a catastrophe. "Generally, in those kind of cases, if [leaks] propagate to be big enough, it will drive your turbine temperatures to their upper redline limits, then the automatic shut down sequences would shut the engine down," he said. "We're talking lots of tubes, we're talking 20, 40 or more tubes before you get to the point at which the temperatures rise enough that it trips a redline sensor and the engine shuts down," he said. "Obviously, if you didn't stop the engine at some point, you would run into real problems. But we believe the redline sensors would keep us out of any serious problems. Of course, you don't want a main engine to shut down during ascent if you can avoid it." Indeed. In an interview with CBS Radio earlier today, Collins discussed the short circuit but presumably had not been told about the presumed nozzle leak. Asked if the crew "dodged a bullet," Collins said "I'm not sure what the right words would be to use." But, she added, "if we had lost another controller, we would have lost an engine. So I was paying very close attention to the performance boundaries on ascent. ... Our pilot, Jeff Ashby, was paying very close attention to the main engines and the electrical system for obvious reasons." The first female shuttle commander, Collins downplayed the potential danger, saying "there's always risk in space flight. There's risk in everything we do, like flying airplanes and driving cars. And our job is minimizing the risk." She then thanked workers at the Kennedy Space Center who prepared Columbia for launch and concluded "I was very confident that we had a great orbiter and great boosters and a great payload to take to orbit." "But sometimes these things happen," Collins said. "And I think what will take place after this is we'll continue to analyze the data, determine what caused the problem and make corrective actions in the future to prevent it from happening again." =================================================================== Shuttle commander cagey about future with NASA (07/25/99) Shuttle commander Eileen Collins, married to a commercial airline pilot and the mother of a three-year-old girl, is making her third space flight. Asked in an interview with CBS Radio if she "definitely" planned to get back in line after landing to await a fourth flight, Collins joked that "I never say 'definitely,' I never say 'always,' I never say 'never,' except right now." "I will be very fuzzy on the answer to that question because I really don't know what I'll do when I get back," she said. "I'll take a look at what the opportunities are, I'll take a look at what my family wants me to do. I really don't want to make a change because I love the job I have right now. I'll just keep my options open." Collins said she had mixed emotions about landing Tuesday and bringing Columbia's mission to a close. "In a way it's going to be hard to come home because I do like being in space so much," she said. "It's a little difficult the first couple of days adjusting to zero G and just getting used to being here again. I guess you could say it's like riding on roller skates, it's a little bit different. But once you adapt after three or four days, it feels almost natural to be up here. "Coming back to do the landing, when you experience a G field again - or the 'gravity storm' as I've heard it called - it is a little difficult to get used to that. So it will make the landing a little more difficult in the orbiter than it is in the shuttle training aircraft that I've been practicing in for so many years. "But I am looking forward to the landing," she said. "I feel very confident. It will be a night landing, we have a full moon, hopefully it'll be a clear night. ... So I feel very confident about the landing. If you ask me what I'm looking forward to the most is, the weather report. I hope we have some good weather forecast." The astronauts spent the day working through a busy research schedule, training a small ultraviolet telescope on Jupiter and the moon, monitoring a variety of biological experiments and periodically firing Columbia's maneuvering jets to help researchers study subtle changes in the extreme upper atmosphere. Early this morning, Collins and Frenchman Michel Tognini chatted with the crew of the Russian space station Mir via ham radio and satellite links. Victor Afanasyev and Sergei Avdeyev congratulated Collins on her "courageous" role while French cosmonaut Jean-Pierre Haignere took a moment to talk with countryman Tognini. "The fact that we're both in space at the same time is great for Europeans," Tognini said. "I hope it will enable us to help move forward the space program in Europe." Avdeyev was launched Aug. 13, 1999, and as of today, he has logged 346 days in space on his current mission and 714 days over three flights. He set the new cumulative space endurance record June 21 when he passed the 679-day mark set by Valery Polyakov. When Mir's crew returns to Earth on Aug. 28, Avdeyev will have logged 380 days in space on his current mission and 748 days overall. =================================================================== Collins looks forward to landing (07/26/99) Shuttle commander Eileen Collins says she's looking forward to her first chance in three flights to actually take manual control of Columbia for a rare nighttime landing at the Kennedy Space Center. Assisted by pilot Jeffrey Ashby, Collins plans to guide NASA oldest space shuttle to a high-speed touchdown at 11:20 p.m. Tuesday. "I'm looking forward to the landing," Collins said in a crew news conference Monday night. "Jeff and I have been training for a night landing since February. We've had a lot of practice. ... I wouldn't say I was anything but really excited about the chance to land the space shuttle. A night landing will be especially challenging, but I think everybody's up to it." Asked if she was disappointed by getting assigned to a relatively short five-day mission, Collins insisted "I'm never disappointed about a space flight." "The most important thing about our flight is the mission and the crew that you fly with," she said. "Just coming up here in space and getting five days to look at the Earth is really great and I would never say I could possibly be anything but extremely happy with this flight." Collins and company accomplished the primary goal of the 95th shuttle mission Friday when they launched the $1.6 billion Chandra X-ray Observatory from Columbia's cargo bay. Since then, the astronauts have been focusing on relatively minor on-board experiments and now, readying Columbia for re-entry and landing (see the next entry for details). The mission has gone remarkably smoothly, although engineers are studying a possible hydrogen leak in the nozzle of one of Columbia's three main engines that apparently prevented the shuttle from reaching its desired orbit. But there was no mission impact and the crew was never in any danger of a catastrophic failure. For her part, Collins said it's too soon to speculate about what might have gone wrong or what corrective action might be needed before the next shuttle flight in September. "I think there's a lot more analysis that needs to be done before we know exactly what happened and I know the engineers, after the orbiter lands, will be waiting to get a good look at that engine to see exactly what it looks like," she said. "I know they suspect there may have been a very small leak somewhere in the nozzle. We had quite a bit of margin on this leak, although it is not normal and I know the shuttle program will take actions in the future to make sure it doesn't happen again." Ashby, making his first shuttle flight, said the presumed leak and a short circuit moments after liftoff that knocked out two engine computers did not cause the astronauts any problems. In fact, he said, the problems encountered during ascent were much easier to handle than the flood of glitches and malfunctions typically served up during simulations at the Johnson Space Center. "I felt like I was on the biggest part of the Astroworld roller coaster for eight minutes," he said of launch. "It was a combination of wanting to yell and continuing to reign myself in and thinking about what was going on going up hill. Compared to our simulator runs, it was actually quite an easy ascent. But physically, much different. The simulator doesn't simulate the Gs, and the shaking and vibrating that we had going up hill, nor just the emotion of lifting off and going to space." Coleman downplayed Columbia's launch glitches, saying the risks of flying on the shuttle are outweighed by the benefits. "It's hard to put a number to risk," she said. "I think of the Hubble Space Telescope. And when I realize how many people's eyes have been opened up to what is going on out in the universe and the fact that we are getting questions answered that we didn't even know we had. It's really just a wonderful thing. "And it isn't something you can put a value or a number on it," she said. "So I do think the Chandra X-ray Observatory is worth every single thing it took us to get it up there. As you know in the space program, it is a risky business and we understand that and our job is to minimize that risk and I feel very comfortable and very safe here in the space shuttle, going up and coming down, because of all the redundant systems we have and because of the people we have back on Earth working for us and examining these problems and making sure they don't happen again." Following the news conference, Collins and Ashby tested Columbia's re-entry systems to make sure the orbiter will be ready for landing Tuesday night. The flight plan called for the astronauts to begin packing up for entry shortly after midnight. =================================================================== X-ray telescope completes second of five critical rocket firings (07/26/99) The Chandra X-ray Observatory fired its maneuvering rockets for the second time late Saturday, continuing a series of "burns" to boost the spacecraft into its final operational orbit. The 11-minute 13-second burn began at 9:47 p.m., raising the low point of Chandra's orbit from 740 miles to 2,134 miles. The high point, or perigee, remained roughly unchanged, at about 44,782 miles. The ultimate target is an orbit with a low point of 6,200 miles and a high point of 87,000 miles. In that orbit, Chandra will spend more than 70 percent of each orbit above an altitude of 37,000 miles where its sensitive instruments will be immune to interference from Earth's energetic radiation belts. Chandra was launched from the shuttle Columbia Friday and boosted into an intermediate transfer orbit by a two-stage solid-fuel booster. Five additional firings by built-in liquid-fuel thrusters are required to complete the journey. The final three maneuvers are targeted for July 29, July 31 and August 2. The next burn will raise the high point of the telescope's orbit to the target altitude while the final two will raise the low point, or perigee. =================================================================== Shuttle Columbia returns to Earth (07/27-28/99) 08:10 a.m. Update: Shuttle crew readies ship for nighttime landing The Columbia astronauts tested the shuttle's re-entry systems late Monday and packed up for landing Tuesday night at the Kennedy Space Center to close out a successful satellite-launching mission. Leaving the $1.6 billion Chandra X-ray Observatory behind in orbit, commander Eileen Collins and pilot Jeffrey Ashby plan to guide NASA's oldest space shuttle to a landing at 11:19:55 p.m. "I'm looking forward to the landing," Collins said in a crew news conference Monday night. "Jeff and I have been training for a night landing since February. We've had a lot of practice. ... I wouldn't say I was anything but really excited about the chance to land the space shuttle. A night landing will be especially challenging, but I think everybody's up to it." With forecasters predicting good weather, Collins and Ashby plan to fire Columbia's twin orbital maneuvering system rockets at 10:19 p.m. to slow the shuttle by 250 feet per second - about 170 mph - just enough to drop the other side of its orbit deep into the atmosphere. About 28 minutes later, Columbia will fall into the discernible atmosphere, bleeding off energy with wide computer-controlled banking maneuvers as it streaks toward Florida. The shuttle will drop below the speed of sound at an altitude of roughly 50,000 feet. From that point on, Collins will take over manual control to guide Columbia back to Earth. "Coming down through about 50,000 feet we go subsonic," she said at a news conference. "We'll be coming in from the west. As we come down through 50,000 feet, we'll be pretty much over Florida. Jeff will be a key part of the landing, he'll be making the calls, he'll be watching what I'm doing. If I get off course, get off glide slope, he'll be right on me, correcting anything that he sees that needs correcting. "We'll be rolling out on final and picking up a signal from the microwave landing system, which will give us more accurate information on our course and glide slope," she said. "At 2,000 feet, we'll be arming the landing gear system and starting a very slow, shallow pre flare. "Keep in mind we are descending at a 20-degree glide slope ... an almost seven-times-higher rate of descent than a commercial airliner. When we get down to about 300 feet, Jeff will put the gear down, at about 200 feet, we'll start a more shallow, final flare and using the lights at Kennedy Space Center, it'll bring us in over the threshold at about 25 or 30 feet and we'll be landing at about 195 knots." Collins has experience flying small, lightweight jets like NASA's T-38 trainers and larger, four-engine transport jets like the Air Force C-141. She said the shuttle has handling characteristics similar to both classes of aircraft. "It's interesting in that the control harmony and the flying qualities in the shuttle, to me it's kind of a mixture of airplanes I've flown in the past," she said. "The pitch axis seems to be a little more sensitive than most airplanes I've flown, it flies a little more like an F-16-type aircraft. In the roll axis, it's a little more lagging, you maybe have to anticipate corrections a little bit sooner. I'd say in the roll axis, it does fly a little bit more like a C-141 than a lighter aircraft." Entry flight director John Shannon said forecasters expect generally good weather, although there's a slight chance of thunderstorms near the shuttle runway that could cause problems. But NASA is not staffing Edwards Air Force Base, Calif., for Tuesday's landing attempt and Columbia's crew will be focused solely on two Florida opportunities on successive orbits. Here are the latest numbers (all in EDT and subject to change; dV: change in velocity; dT: duration of rocket firing): TIME............EVENT..............NOTES 10:19:02 p.m....Deorbit ignition...dV: 250 fps; dT: 02:15 10:48:18 p.m....Entry interface....Columbia hits the atmosphere 11:15:40 p.m....Mach 1.............Shuttle below the speed of sound 11:19:59 p.m....Landing............KSC landing on orbit 80 11:53:55 p.m....Deorbit ignition...dV: 250 fps; dT: 02:15 12:23:20 a.m....Entry interface....Columbia hits the atmosphere 12:50:32 a.m....Mach 1.............Shuttle below the speed of sound 12:54:49 a.m....Landing............KSC landing on orbit 81 "Right now, the flight control team is not tracking any entry issues at all," Shannon said. "The weather looks really good. The forecast looks much like the launch forecast was: There are no wind issues, there are no cloud issues. The only constraint we have currently in the forecast is the potential for rain showers or thunderstorms within 30 miles. That's pretty typical Florida weather for this time of the year." If Collins is unable to land in Florida Tuesday night or Wednesday morning, the astronauts will remain in orbit an extra day and try again late Wednesday. In that case, Edwards probably would be staffed. Here are the estimates for a Wednesday landing: TIME............EVENT..............NOTES 10:18:00 p.m....Deorbit ignition...Data TBD 11:17:00 p.m....Landing............Kennedy, orbit 95 11:45:00 p.m....Deorbit ignition...Data TBD 12:43:00 p.m....Landing............Edwards AFB, orbit 96 11:53:00 p.m....Deorbit ignition...Data TBD 12:51:00 a.m....Landing............Kennedy, orbit 96 01:19:00 a.m....Deorbit ignition...Data TBD 02:18:00 a.m....Landing............Edwards AFB, orbit 97 "If for some reason we were unable to come home [Tuesday], we would consider calling up Edwards," Shannon said. "But we're going to delay that decision until we see what happens tomorrow night. Like I said, we're not tracking any kind of entry issues at all, everything looks really good on Columbia, the crew is doing really well and we're looking forward to a good entry tomorrow night." The forecast for Wednesday is generally the same, with good conditions expected. 11:40 p.m., 07/27/99, Update: Shuttle Columbia glides to smooth touchdown The space shuttle Columbia, with NASA's first female commander at the controls, glided to a ghostly moon-washed touchdown tonight, leaving a $1.6 billion X-ray telescope behind in orbit and opening a new door for women with the right stuff. "Houston, Columbia has the runway in sight," commander Eileen Collins radioed as she guided the shuttle through a sweeping right overhead turn. Video from inside Columbia's cockpit showed the final approach and landing with unprecedented clarity. Showing no sign of the pressure any first-time commander must feel, Collins, 42, flew the 110-ton Columbia to a picture-perfect landing on runway 33 at the Kennedy Space Center at 11:20:35 p.m. to close out a 2-million-mile voyage spanning 79 complete orbits since blastoff Friday. Barreling down the three-mile-long runway, Collins deftly brought the nose down, pilot Jeffrey Ashby released a braking parachute and Columbia rolled to a halt after a fiery hour-long plunge to Earth. Mission duration was four days 22 hours 49 minutes and 35 seconds. "Houston, Columbia, wheels stopped," Collins radioed as the shuttle coasted to a halt. "Roger wheels stopped, Columbia, welcome home," replied astronaut Scott Atman from mission control. "Eileen, to you and the crew, just an outstanding job deploying Chandra and bringing Columbia home for a beautiful landing." It was the 12th night landing in shuttle history, the 19th landing in a row in Florida and the 26th Kennedy touchdown out of the past 27. With Columbia's crew back on the ground in good shape, engineers were standing by to begin an examination of the shuttle's main engines and their attached control computers. A short circuit five seconds after launch, possibly located inside a computer bolted to main engine No. 1, knocked out another engine controller and left the astronauts one failure away from an engine shutdown and an aborted launch. Equally disconcerting, main engine No. 3's nozzle apparently started leaking explosive hydrogen rocket fuel shortly after ignition, causing the engine to run hot and consume an extra 4,000 pounds of liquid oxygen in a bid to compensate. As a result, Columbia's initial altitude was seven miles lower than planned. That had no impact on the mission, but engineers need to figure out what went wrong and take corrective action before the shuttle Endeavour can be cleared for launch in September as currently planned. But for Collins, Ashby, Catherine "Cady" Coleman, Steven Hawley and Frenchman Michel Tognini, the immediate concern was safely shutting down Columbia's myriad systems and climbing out for reunions with friends and family members. All five plan to fly back to Houston later this morning where Vice President Al Gore is expected to be on hand to welcome them home. On hand to greet the astronauts in Florida was NASA Administrator Daniel Goldin, embroiled in a fierce political battle with lawmakers in the House of Representatives who are attempting to cut the agency's budget as part of a tax-cut package. "The NASA team just launched Chandra, the world's most powerful space telescope," Goldin said Monday. "Today, we will have to turn it back on Washington to see what remains of the NASA budget." A House subcommittee has recommended cutting NASA's budget by $1.325 billion, or 11 percent below President Clinton's proposed 2000 budget. Projected over five years, Goldin says, the cuts would total more than $5 billion. "Up until now, NASA has always stepped up to the budgetary challenge," Goldin said. "This time the NASA team plans to fight. These cuts would gut space exploration. They may force the closure of one to three NASA centers, and significant layoffs would most certainly follow." NASA managers say the cuts, if approved, could force the agency to cancel an infrared telescope - the next Chandra-class "great observatory" - and a planned replacement for the Hubble Space Telescope. In addition, it likely would stop robotic missions to Mars after 2001 - including a planned sample return mission in 2005 - and eliminate plans for a spacecraft that would search for Earth-like planets around other stars. "The House action gives new meaning to 'deep impact'," said Louis Friedman, director of The Planetary Society. "The space science cuts are the most devastating in NASA's history and effectively curtail space exploration after 2001. "NASA's budget has been reduced every year since 1992, and the proposed cuts would be the coup de gr‰ce," Friedman said in a statement. Gore's presence at Ellington Field near the Johnson Space Center later today might provide a morale boost of sorts. But it's not yet clear how much concrete support the Clinton administration might provide given the other chips on the budget table. For Columbia's crew, landing marked a concrete end to a long journey, one that began well over a year ago when the quintet was assigned to mission STS-93. The goal was to launch the $1.6 billion Chandra X-ray Observatory, the third of four planned "great observatories" designed to study the cosmos across the entire electromagnetic spectrum. The flight originally was scheduled for last August, but it was put on hold to correct software problems with the telescope. Launch was rescheduled for early April only to be delayed again, this time because of work to replace delaminating circuit board and a probe into the failure of an Air Force booster similar to the one slated for use by Chandra. But after two last-minute launch delays last week, Columbia finally rocketed into orbit on Friday. Seven hours and 17 minutes later, Coleman and Tognini launched Chandra, sending the giant telescope on its way. It's inertial upper stage booster worked flawlessly and engineers are in the process of maneuvering the satellite into its final operational altitude. So far, the telescope has had no technical problems of any significance. 07:00 a.m., 07/28/99, Update: Collins praised for smooth landing With the shuttle Columbia back on the ground, engineers are assessing the possible impact of a short circuit during launch Friday and a potentially dangerous hydrogen leak in one of the ship's main engines. Commander Eileen Collins, the first female shuttle commander, said it's too soon to speculate about whether the anomalies represent significant issues or not. But, she emphasized, "I think we definitely need to take a very close, hard look at what happened. We don't want this to happen again on a future mission. All the attention that's being paid by the NASA engineers, the managers and the program folks is very appropriate. We take it very seriously. We're definitely going to find out what caused it and work it out." At a post-landing news conference, Collins' crewmates praised their commander, saying touchdown late Tuesday was so smooth several of them did not even know the wheels had hit the runway (see the 11:40 p.m. update immediately below for landing coverage). "I get asked a lot how it is to fly with Eileen," said pilot Jeffrey Ashby. "I think the women's soccer team captain summed it up best: Eileen rocks! Eileen got up every single morning and was at work hard within 10 minutes and went like an afterburner until just before sleep. I was really impressed. I learned a lot from Eileen and it was a real pleasure to fly with her. She did a tremendous job." As for landing, Ashby, a former Topgun Navy fighter pilot, said Collins was "within one knot of the targeted touchdown speed and within about 100 feet of the touchdown point. It was just absolutely beautiful from where I sat. I was really impressed." Steven Hawley was sitting behind the two pilots, serving as flight engineer. "From where I sit, coming in [nose high] as we do, I can't see out so I don't know when we land until I feel it," he said. "And I wasn't sure we had landed. It was really smooth." But the astronauts spent most of their time at the news conference fielding questions about the two launch problems that sent a scare through mission control last Friday. A short circuit five seconds after liftoff knocked out two main engine control computers and left the crew one failure away from an engine shutdown. In addition, the nozzle of main engine No. 3 began leaking hydrogen rocket fuel shortly after ignition. Had the leak worsened, an engine shutdown could have occurred, forcing the crew to attempt a risky emergency abort. "The bus [circuit] short we saw during ascent, I would consider a significant anomaly that we will have to look at in depth," said Bill Gerstenmaier, shuttle integration manager at the Johnson Space Center. "The hydrogen potential leak we saw during ascent, it looks like several of the tubes are damaged in the nozzle and it looks like we had a real hydrogen leak there," he said. "That's also a very significant problem we need to look at and work on. The team's have good plans for both of those problems in terms of troubleshooting." Main engine nozzles are made up of more than 1,000 three-eighths-inch-wide tubes. A portion of liquid hydrogen fuel is diverted through the tubes to cool the nozzle before it is routed back to the main combustion chamber for burning. Engineers believe three or four of the tubes making up engine No. 3's nozzle cracked, or split open, allowing up to 2,500 pounds of hydrogen to spill out during Columbia's climb to space. Collins, who examined the engine with binoculars after landing, said she saw what appeared to be three small holes in adjacent tubes running in a diagonal pattern. During launch, the engine ran about 100 degrees hotter than expected as it gulped 4,000 pounds more liquid oxygen than its neighbors to compensate for the lost fuel. As a result, the shuttle's oxygen tank ran dry, the engines were commanded to shut down a split-second early and Columbia ended up seven miles lower than its initial target. NASA managers say the leak did not pose the threat of a catastrophic failure. Had it worsened, operating temperatures ultimately would have climbed above pre-set limits and Columbia's computers would have simply shut the engine down. Depending on when that happened, Collins could have been forced to make a risky emergency landing in Florida or Africa. But it would not have been a catastrophic failure. It is a serious issue nonetheless and one that will have to be resolved before Columbia's next flight in September. "We plan some boroscope inspections of the nozzle tubes, to go into the tubes and go toward where the break appears to be. Then we'll probably section that piece of the nozzle out, actually physically remove the tubes and send them to [engine-builder Rocketdyne] for some microscopic and metallurgical analysis. "We should have most of the boroscoping done by the Thursday timeframe and then we'll kind of be in a position to understand what the implications are for future missions. Right now, we really won't know until we get the microscopic analysis and the metallurgy done." As for the short circuit, engineers believe a problem in the computer controller mounted on Columbia's center engine caused a 13.3-amp short that knocked that controller our of action, along with a controller on main engine No. 3 that was tied to the same circuit. Engineers plan to start trying to pinpoint the short Friday and if all goes well, NASA managers should have some answers by Monday. "Considering the significance of those two events, the shuttle hardware performed exactly as we expected," Gerstenmaier said. "It's pretty neat to see a major bus short like this stay isolated just to this particular phase of the AC circuit, not to propagate to another system. "In the hydrogen leak, it did exactly the same thing. The chamber pressure dropped off a little bit, we can see at ignition the oxidizer valve opened just like it was supposed to, brought the chamber pressure up, the thrust level was maintained. So again, that shows the robustness and resilience of the system to take two fairly significant failures but yet able to achieve orbit and achieve a mission with absolutely no mission impact." But, he quickly added, "we can't let down, we've got to make sure we understand these failures and we understand what's going on before we go fly. And we'll do that with these two failures." =================================================================== Engine leak caused by debris impact (07/30/99) NASA engineers say the nozzle of a main engine aboard shuttle Columbia apparently was dented by impact from a piece of internal debris during ignition July 23, compressing three hydrogen coolant tubes and causing a trio of potentially dangerous leaks. Some 2,550 pounds of hydrogen leaked out during Columbia's climb to space, forcing main engine No. 3 to run hot by burning an additional 4,000 pounds of liquid oxygen propellant to compensate. As a result, the oxygen tank ran dry and Columbia's engines were commanded to shut down a split-second early, leaving the shuttle seven miles lower and 10 mph slower than planned. After Columbia's landing Tuesday, engineers carried out a detailed inspection of main engine No. 3's nozzle and found a dent across three of its hydrogen coolant lines. Main engine nozzles are made up of more than 1,000 three-eighths-inch-wide tubes. A portion of liquid hydrogen fuel is diverted through the tubes to cool the nozzle before it is routed back to the main combustion chamber for burning. Bill Gerstenmaier, shuttle integration manager at the Johnson Space Center, told reporters today the dent across three tubes was caused by impact with a piece of debris. "What we surmise has happened is that a piece of debris, or some kind of object, hit the tubes and that's evidenced by this dent," he said. "The tubes were typically deformed and compressed. The tube wall thickness necked down because of the impact. Then the hole was caused by the high pressure hydrogen in the tube rupturing out through the thinned wall. "So what we see here is evidence of an impact that scraped away some of the metal, or pushed some of the metal and thinned it out enough so it could no longer hold pressure and the tube ruptured and created the three holes we see." Engineers believe the debris originated in the combustion chamber of main engine No. 3. Oxygen is delivered to the chamber through more than 600 injectors, small tubes cooled by hydrogen. Two of the injectors in engine No. 3 were plugged because of commonplace manufacturing defects. Tubes with such defects typically are bored out and certified for a limited number of flights. After that, because the tubes might have weakened over time, they are plugged to prevent any chance of a rupture that could spew oxygen into a hydrogen-rich environment and trigger a catastrophic fire. As it turns out, one of the two plugs inside Columbia's engine No. 3 is missing. Engineers suspect it was blown free during ignition, hitting the nozzle below and causing the dent and leaks in question. An investigation team currently is working to confirm that theory and to determine what modifications might be needed before the shuttle Endeavour can be cleared for launch in September. Endeavour is equipped three upgraded Block 2A engines. A dozen such powerplants are currently in the fleet and only one of them has a plug in it similar to the ones in question. That one engine is slated for use by Endeavour and it remains to be seen whether the powerplant will be cleared for flight as is. NASA managers say the leak during Columbia's launch did not pose the threat of a catastrophic failure. Had it worsened, operating temperatures ultimately would have climbed above pre-set limits and Columbia's computers would have simply shut the engine down. Depending on when that happened, Collins could have been forced to make a risky emergency landing in Florida or Africa. But it would not have been a catastrophic failure. ===================================================================