STS-92 MISSION ARCHIVE (COMPLETE) Updated: 10/24/00 Space Station Assembly Mission 3A: Z1 Truss, PMA-3 By William Harwood CBS News/Kennedy Space Center The following copy originally was posted on the Current Mission space page at http://cbsnews.cbs.com/network/news/space/current.html. Comments, suggestions and corrections welcome! TABLE OF CONTENTS STS-92 mission preview (09/20/00) Shuttle countdown begins (10/03/00) Weather only marginally acceptable Thursday (10/03/00) Hurricane Keith takes westerly track (10/03/00) Russians troubleshoot more battery trouble on Zvezda (10/04/00) Forecasters stick with marginally optimistic forecast (10/04/00) Shuttle launch delayed by ET bolt issue, sluggish valve (10/05/00) Valve fix in work; ET bolt issue remains unresolved (10/06/00) Bolt issued resolved; shuttle cleared for launch (10/09/00) Launch delayed 24 hours by high winds (10/09/00) Shuttle launch delayed by debris on external tank (10/10/00) Discovery rockets into orbit (10/11-12/00) Shuttle's KU-band antenna fails (10/12/00) Discovery docks with international space station (10/13/00) Z1 truss installed after short circuit delay (10/14/00) Astronauts wire up Z1 truss in successful spacewalk (10/15/00) New docking port attached to station in second spacewalk (10/16/00) Solar array power converters installed in third spacewalk (10/17/00) Jetpacks tested in fourth spacewalk (10/18/00) Astronauts test gyroscope; complete station outfitting (10/19/00) Discovery undocks from space station (10/20/00) Astronauts test steering systems, pack for landing (10/21/00) High crosswinds force 24-hour landing delay (10/22/00) Astronauts delayed again by bad weather (10/23/00) Shuttle Discovery finally glides home (10/24/00) =================================================================== Shuttle mission preview (09/20/00) Editor's Note... The following story was written for Spaceflight Now before Discovery's initial Oct. 5 launch date. It is posted here by permission. The shuttle Discovery is poised for blastoff Oct. 5 on the 100th shuttle mission, a high stakes flight to mount an 18,400-pound truss housing four stabilizing gyroscopes and critical electronic gear on the international space station. While providing fuel-saving stability for the growing lab complex, the so-called Z1 truss also features the station's main communications antenna and will serve as the temporary attachment point for a huge set of power-producing solar arrays slated for delivery in December. Operating the shuttle's 50-foot-long robot arm, Japanese astronaut Koichi Wakata is charged with moving the boxy Z1 truss from Discovery's cargo bay to the top, or zenith, port of the U.S. Unity node, one of the three modules currently making up the space station. Then, four back-to-back spacewalks by a quartet of astronauts working in two-man teams will be staged to wire up the truss and prepare it for arrival of the solar arrays in December. The spacewalkers also will help mount a pressurized docking tunnel to Unity's Earth-facing, or nadir, hatch, which will then serve as the primary docking port for upcoming shuttle visits. The forward-facing port currently used for shuttle dockings is where the U.S. laboratory module Destiny will be attached in late January. During the fourth spacewalk planned by Discovery's crew, Jeff Wisoff and Michael Lopez-Alegria also will test fly small emergency jetpacks that serve as the last line of defense for space station assembly crews. Should a spacewalker ever become untethered and drift away into open space, the jetpack could be used to fly back to the safety of an airlock. To make sure, Wisoff and Lopez-Alegria will take turns hauling each other back to Discovery's airlock in a simulated emergency. Once the spacewalks are out of the way, Discovery's international seven-member crew plans to re-enter the space station to deliver supplies and to complete the electrical integration of the Z1 truss. "We're looking forward to a very rich, varied mission," said spacewalker William McArthur. "It's got anything you could ever want to do in space. If you're a real space cadet at heart, it's just a dream come true." Said Lopez-Alegria: "If you're in the space business, it just doesn't get any better than this." Or more difficult. Shuttle mission STS-92 rivals a Hubble Space Telescope repair mission in sheer complexity. But as NASA launches a steady stream of station assembly flights over the next five years, complex multi-spacewalk shuttle missions will become the rule, not the exception. The shuttle Atlantis's launch Sept. 8 on the 99th shuttle mission was the first of nine flights planned over a 12-month period, NASA's most intense period of launch activity since the pre-Challenger era. The agency plans to routinely launch seven flights a year with a surge capability of eight. "Flying eight flights a year was not outside the scope of what we did in the early part of the program and we have a fairly good understanding of what it takes to do that," said veteran shuttle flight director Phil Engelauf. "I will concede that also manning the station consoles and flying two vehicles at the same time does put an increased stress on the available manpower. "It's challenging, it's demanding, it's hard to work multiple projects at the same time and that's what we're going to have to do," he said. "But at the same time, that's what people want to do, that's why we came here. We'd like to fly eight flights a year more than we'd like to fly two or three or four flights a year. "I think now that the training has gotten rolling and we're picking up steam, I think you're going to see people hitting their stride, with a renewed sense of enthusiasm, really invigorated by the pace rather than being drawn down by it." Discovery is scheduled for launch from pad 39A at the Kennedy Space Center around 9:39 p.m. on Oct. 5. As with all space station assembly flights, the exact launch time will not be determined until a few hours before liftoff based on final radar tracking of the space station. The launch window, which will last between two-and-a-half and five minutes, will open at the moment Earth's rotation carries the launch pad into the plane of the space station's orbit. By launching directly into the target's orbital plane, the shuttle can save fuel and improve the odds of pulling off a successful flight even if engine problems develop. At the controls for Discovery's 28th flight will be veteran shuttle commander Brian Duffy and rookie pilot Pamela Melroy, the third woman to serve as a space shuttle pilot. Their crewmates are McArthur, Lopez-Alegria, Wakata, Jeff Wisoff and Leroy Chiao. "It doesn't seem like it's been a hundred flights," said Bill Gerstenmaier, director of shuttle program integration. "But it has and we've learned a tremendous amount during all those years. "I think it's kind of fitting that the 100th flight comes during the build up of the space station," he added. "We've done tremendous things with the shuttle, it's been unbelievably versatile vehicle. Then to see it carry on and start building space station, which is really a huge endeavor for us, is really a neat thing to see." After a two-day orbital chase, Duffy will guide Atlantis to a docking with the space station on flight day three - around 4:15 p.m. on Oct. 7 - less than one month after the crew of shuttle Atlantis delivered three tons of supplies and equipment to the outpost. Discovery will dock at a pressurized mating adaptor extending from the Unity module's forward axial port. On the other side of the node is another pressurized mating adaptor leading to the Russian-built NASA-financed Zarya propulsion module. Attached to Zarya's far port is the new Russian command module Zvezda, which will provide the station's initial crew quarters, computer control and the propulsion needed to keep the lab at a safe altitude. The three-module station stretches some 13 stories and masses 67 tons. Atlantis's crew outfitted Zvezda and loaded it with supplies for the station's first full-time crew. Expedition One commander William Shepherd, Yuri Gidzenko and Sergei Krikalev, scheduled for launch Oct. 30, plan to spend four months aboard the outpost before being relieved. But before they get there, Discovery's crew will continue station assembly, delivering the first in a series of new components that will provide the power, stability and working space needed to turn the station into a functional, permanently manned space laboratory. And the astronauts plan to hit the deck running. Just two-and-a-half hours after docking, the crew will open hatches between the orbiter and the station and float into NASA's roomy Unity node to prepare the common berthing mechanism on the module's zenith port for the arrival of the Z1 truss. The common berthing mechanism, or CBM, is a complex set of interlocking motor-driven petals and latches that will firmly seal space station modules together. The system will be put to the test for the first time during Discovery's mission. The day after docking, Wakata plans to pluck the massive truss from the shuttle's cargo bay and carefully mount it atop Unity. Melroy, working beside Wakata on the shuttle's aft flight deck, will control the operation of the interlocking common berthing mechanisms that will latch the Z1 truss into place. Later that day, the astronauts will connect ground straps between Unity and the Z1 truss, working in a cramped vestibule where the truss is attached to the node. Other crew members will enter the Russian Zarya module to begin stowing fresh supplies. The Z1 truss houses four large gyroscopes that will be used to keep the station stable and to change its orientation from time to time without having to burn limited on-board supplies of rocket fuel. The gyros will not actually be used until after the U.S. laboratory module arrives in late January. But during ground testing, a critical Hall effect sensor that monitors how fast a gyro is spinning failed after prolonged exposure to low temperatures like those the real Z1 gyros might see over the next five months. As a result, engineers removed the heater units on the flight hardware, reset their thermostats to a higher temperature and re-installed them in the Z1 truss. In addition, laptop computer routines were written to give the station's on-board crew the ability to directly control the heaters if necessary. "They're still doing some tests to make sure all that works out correctly," Gerstenmaier said Sept. 14. "So there's still some work they have to do to verify those procedures to get that in shape. But the hardware's ready to go." There are other temperature concerns as well. The Z1 truss is not equipped with any active heating or cooling systems and it is very sensitive to temperature. Once Discovery is docked to the station, the Z1 truss must be installed within 20 to 25 hours to prevent ammonia lines from over heating. But Z1 temperature constraints also pose problems for the shuttle. "We installed a canopy, or a series of blankets, over the airlock to shade our water lines that run between the orbiter and the airlock," Gerstenmaier said. "That was done because the sun angles that the station wants are incompatible with the water lines that are running to the airlock." Assuming Z1 installation goes smoothly, Chiao and McArthur will stage the first of the crew's four spacewalks the next day. "After the Z1 has been berthed and after Pam has gotten the CBMs to connect the Z1 physically to the structure, Bill McArthur and I will go out on the first EVA (spacewalk) and begin outfitting the Z1 truss," Chiao told reporters. "We'll be connecting cables between the Z1 and the node and we'll also be relocating the S-band antenna as well as taking the KU dish out, attaching that to a boom and then rolling that boom out. We'll also be transferring one of the tool boxes over to its location on the Z1 truss. "We're hoping everything goes very smoothly and we'll get a good kickoff on the first EVA to set the tone for the rest of the spacewalks," he said. The next day, Wisoff and Lopez-Alegria will float into Discovery's cargo bay to assist Wakata in attaching a pressurized mating adaptor to Unity's nadir hatch. "It's called PMA-3 and it's held in the back of the space shuttle on a Spacelab pallet," Wisoff said. "It's bolted on and the only way to get it off is to go out and manually undo these bolts. So Mike and I will go out on EVA 2, go to the back of the payload bay, undo all the bolts on PMA-3 and then Koichi will pick it up with the arm and carry it over to the nadir port of the node." Attaching PMA-3 is especially tricky because Wakata will have limited visibility and little margin for error. He will be assisted by the Canadian-built Orbiter Space Vision System, which uses television cameras, computers and targets to compute a module's exact position and orientation. "Mike and I will position ourselves on opposite sides to watch it, to make sure the alignment is good," Wisoff said. "We have a Space Vision System to help us do that, but if it should fail or not work as planned, Mike and I will already be outside and positioned to help give Koichi directions on how to align it. "Once it's attached to the node, we'll set up the arm," Wisoff continued. "I'll get on the arm and Mike will undo the umbilicals that are on the mating adapter. Then we'll go and attach all those umbilicals to the node to give the PMA the necessary power and data that'll be needed later." The space station's first set of U.S. solar arrays will be mounted atop the Z1 truss in December. The electricity generated by the arrays will be converted to the proper voltage by two DC-to-DC converter units, or DDCUs, mounted on the Z1 truss. Chiao and McArthur will install both DDCUs during the third spacewalk. With Chiao anchored to the end of the robot arm, Wakata will move him between the shuttle and the truss to retrieve the DDCUs. "Koichi's going to thread the needle on this one and stick Leroy, on the end of the arm, between the edge of the payload bay and underneath Z1 so he can go to the sidewalls, release these DC-to-DC converter units and then bring them back up and put them on the right side of the space station," McArthur said. If all goes well, Wisoff and Lopez-Alegria will carry out the mission's fourth and final spacewalk the next day. During the first part of the excursion, the duo will prepare the Z1 for the attachment of the P6 solar arrays in December. The 24,547-pound P6 array will consist of a base that will attach to the Z1 truss. From that base, four panels will unfurl stretching 240 feet from tip to tip, or one-and-a-half times the current length of the three-module space station. The huge arrays will generate nearly 100 kilowatts of power and make the station the third brightest object in the night sky when it passes overhead at dawn or dusk. Wisoff and Lopez-Alegria will spend the second half of the final spacewalk testing their SAFER jetpacks. "The SAFER is a cold gas, sort of Buck Rogers kind of backpack that we use to, in the event that we should become untethered from the shuttle, we can actually use it to rescue ourselves and fly ourselves back," said Lopez-Alegria. "So actually we're going to do some flying, kind of like a test program, of this SAFER," he said. "Each of us will perform one of those flights. At the very end of the EVA, we're going to take the other, who will sort of pretend that they're incapacitated, and translate with them through the payload bay and actually put them in the airlock." The day after the final spacewalk, the astronauts will re-enter the space station one more time to wrap up the delivery of supplies and other equipment needed by the station's first full-time crew. They also will do a bit more work to complete the electrical hook up of the Z1 truss. If all goes well, the astronauts will re-seal the station Oct. 13, undock the following day and land back at the Kennedy Space Center the afternoon of Oct. 16. Exactly two weeks later, Shepherd and his crewmates are scheduled to blast off from Kazakhstan to open a new era of around-the-clock station activity. The P6 solar array will be launched a month later and the U.S. lab module, Destiny, is scheduled to arrive in late January. "It'll become a home for our astronauts and cosmonauts and international crews as well as a world-class research facility," said station program manager Tommy Holloway. "This is an exciting time in the history of human space flight," he said. "There are going to be a lot of challenges in front of us, a lot of difficult problems to solve and it's a good time to be in this business. I am excited about where we are and what we have in front of us." =================================================================== Shuttle countdown begins (10/03/00) The shuttle Discovery's countdown to launch Thursday on the 100th shuttle flight began on time today at 12:00 a.m. at the Kennedy Space Center. There are no technical problems of any significance at pad 39A but agency managers continue to monitor Hurricane Keith and possible weather problems that could prompt a delay. As of this writing, Keith does not appear to threaten either the Kennedy Space Center or the Johnson Space Center near Houston. =================================================================== Weather only marginally acceptable Thursday (10/03/00) With the shuttle Discovery's countdown underway, forecasters are predicting marginally acceptable weather for launch Thursday night at 9:38:26 p.m. There are no technical problems of any significance at pad 39A and NASA test director Steve Altemus said today weather is the only concern as the agency gears up for its 100th shuttle mission. "The launch team is not working any issues in the count at this point," Altemus said. "The flight and ground systems are performing well and we're all looking forward to putting another piece of the international space station into orbit Thursday night." Weather permitting, of course. Discovery's launch window will last just two and a half to five minutes - the exact duration will not be computed until Thursday afternoon - giving NASA no time to wait for conditions to improve. A large area of tropical moisture is moving north across Florida today, soaking the space center with heavy rain. While forecasters expect the clouds to begin thinning out by Thursday afternoon, there is still a 40 percent chance of showers and thick cloud cover at launch time that could force a delay. The outlook is similar for Friday evening when thunderstorms ahead of an approaching cold front are expected to pound the Kennedy Space Center area. Conditions are expected to be worse Saturday. While the cold front will dry out the air over central Florida, it is expected to produce higher-than-allowable crosswinds at the spaceport's emergency runway. Conditions are 60 percent "no go" Saturday. "If I had to pick, of the three days I think that the most likely would be Thursday," said John Weems, a shuttle weather officer with the 45th Space Wing at the Cape Canaveral Air Force Station. But NASA's launch strategy calls for making two back-to-back launch attempts Thursday and Friday, if necessary, and then to stand down a day to give the launch team time to rest. A third launch try would be scheduled for Sunday. Along with monitoring Florida's weather, NASA managers also are monitoring the progress of Hurricane Keith in the Gulf of Mexico. The storm is now predicted to strengthen and move north toward the Lake Charles, La., area. But the cold front approaching the Cape is expected to sap the hurricane's energy when the two collide later this week. Forecasters do not expect the storm to disrupt mission control operations at the Johnson Space Center south of Houston. "The mitigating factor with landfall is by the time it approaches the Gulf Coast with its current movement is that it's going to actually run into that cold front," said Weems. "If it does, that will effectively kill th tropical system." The weather will be assessed later today at a standard launch-minus-two-day management review at the Kennedy Space Center. The launch team could be directed to delay or re-order some countdown events to give forecasters more time to monitor Keith's actual progress. But as of this writing, that would not appear to be necessary. Assuming no changes are ordered, the countdown will resume at 8 p.m. this evening at the T-minus 27-hour mark after a four-hour built-in hold with the loading of liquid hydrogen and oxygen to power the shuttle's electrical generators. The shuttle's aft engine compartment has been closed for flight as have the ship's two 60-foot-long payload bay doors. "We're clean and green," said launch manager Bill Dowdell. This status report will be updated after today's 4 p.m. pre-flight news conference. =================================================================== Hurricane Keith takes westerly track (10/03/00) The National Hurricane Center in Miami now predicts tropical depression Keith will steer a westerly course through the Gulf of Mexico, posing no major impact on the Houston area. Flight controllers at the Johnson Space Center, meanwhile, have updated the shuttle Discovery's launch window for Thursday. The window now has two "panes," providing opportunities to dock with the international space station on flight day three or four. Flight day three is the preferred option. Here are the numbers: DATE....WINDOW OPEN.....LAUNCH TIME......WINDOW CLOSE...RENDEZVOUS 10/05...09:33:27 p.m....09:38:26 p.m....09:43:26 p.m....Flight day 3 09:36:36 p.m....09:41:36 p.m....09:46:35 p.m....Flight day 4 While the flight-day-three window above theoretically opens at 9:33:27 p.m., the launch time remains 9:38:26 p.m. That is the moment Earth's rotation will carry pad 39A into the plane of the space station's orbit, minimizing the propellant necessary to achieve the desired orbit. Again, even though two window panes are available Thursday, NASA will opt for the flight-day-three opportunity if at all possible. =================================================================== Russians troubleshoot more battery trouble on Zvezda (10/04/00) Editor's Note... The following story was written for Spaceflight Now and is posted here by permission. As NASA readies shuttle Discovery for launch Thursday on a space station assembly mission, Russian engineers are troubleshooting yet another perplexing battery failure in the station's new Zvezda command module. Launched July 12, Zvezda provides the lab's initial crew quarters, computer control and propulsion. It is equipped with eight batteries to provide power when the station is in Earth's shadow, three of which were installed during a shuttle visit last month. One of those just-installed powerpacks - battery No. 5 - cannot hold a charge, possibly because of a poor connection somewhere in the wiring connecting the battery to its charger, known as a PTAB, and a voltage controller, known as a BUPT. Battery No. 5 has been off line since the shuttle Atlantis departed last month. Russian engineers took a second battery off line over the weekend when it failed to operate properly during a charging cycle. It is not yet clear what might be wrong with battery No. 4. Despite the failures and uncertainty about the ultimate health of Zvezda's remaining batteries, the station's first full-time crew - commander William Shepherd, Yuri Gidzenko and Sergei Krikalev - remains on track for blastoff Oct. 30. Robert Cabana, a senior station manager and veteran shuttle commander, said today a spare battery charger and a new controller will be launched to the station aboard an unmanned Progress supply ship in mid November. In the meantime, he said, "the Russians are evaluating what caused battery four not to function properly. They haven't determined what it specifically is right now." "But the plan would be to fly up a spare BUPT and PTAB and between batteries five and four come up with a good system between them, once the crew got up there," Cabana said. "The loss of battery four is no impact to launching the hardware for (the next two shuttle flights), it just decreases our redundancy in the service module. "We still have six good strings, we can go down to five and still meet our requirements," he added. "So the plan right now is to get the crew up there and allow them to troubleshoot the problem with spare parts and fix it." Cabana said Shepherd's crew can be launched as long as Zvezda has five operational batteries and possibly as few as four, depending on the nature of the failures and the work reqired to make repairs. The Russians have had numerous problems with batteries, PTABs and BUPTs in recent months and NASA carried up replacement parts for all six powerpacks aboard the Russian-built, NASA-financed Zarya module. But Cabana said the Russians are "fairly confident" the remaining batteries in the Zvezda module will work properly. And in any case, Shepherd's crew could live aboard the station with just four operational batteries if necessary. At the Kennedy Space Center, work to ready Discovery for blastoff Thursday night continues on track despite torrential rain from a mass of tropical air slowly moving north across Florida. Forecasters continue to predict a 60 percent chance conditions will improve enough by late Thursday to permit a launch at 9:38 p.m. NASA plans to make two back-to-back launch attempts Thursday and Friday, if necessary, before standing down a day to give the launch team a chance to rest. The goal of the 100th shuttle mission is to deliver an alternate shuttle docking port and a massive 18,300-pound truss that houses four stabilizing gyroscopes and the station's main communications equipment. The Z1 truss also will serve as the temporary mounting point for a huge solar array segment that is scheduled to be attached in December. Discovery's crew plans to stage four back-to-back spacewalks to connect the Z1 truss atop the U.S.-built Unity module and to hook up the new docking adaptor to Unity's downward-facing hatch. "The shuttle missions that have gone to station so far have been extremely successful in that we've built a little, tested a little and provided a lot of equipment and supplies to get ready for permanent flight crew presence in space," said shuttle program manager Ronald Dittemore. "This next mission, STS-92, takes the level of complexity up a notch over the last two missions. It's one of the most complex station assembly flights that we will conduct." The Discovery astronauts have no plans at present to enter the Zvezda module, much less do any battery troubleshooting. But Cabana said engineers are studying the timeline to determine if such work might be possible. "The ops team is looking at that right now," he said. "So far, our Russian partners have not asked us to do that. In fact, there is some feeling on their part that they'd just as soon wait until they got the (full-time) crew up there. "But we are coordinating with each other to see if there was time we could work into the timeline to have the crew ingress in ... to gain a look at the problem and do some troubleshooting. But right now, it's not planned." =================================================================== Forecasters stick with marginally optimistic forecast (10/04/00) The shuttle Discovery's countdown to launch on the 100th shuttle mission continues to tick smoothly toward blastoff Thursday night at 9:38:26 p.m. There are no technical problems at pad 39A and the only concern remains the possibility of showers that could cause a delay. A broad mass of tropical air has soaked the Kennedy Space Center with torrential downpours over the past two days. But John Weems, a shuttle weather officer with the 45th Space Wing at the Cape Canaveral Air Force Station, is sticking with a 60 percent "go" forecast based on computer models that indicate slightly improving conditions Thursday. "All the models are in agreement now," he said at today's countdown status briefing. "The clouds are going to start to pull out of the area so now we're worried about where this moisture is really focused. "I think as this low moves off from the coast, conditions look like they'll be more acceptable than they will be unacceptable." To reach the international space station, Discovery must take off within five minutes of the moment Earth's rotation carries the launch pad into the plane of the target's orbit. That theoretical window will open at 9:33:27 p.m. Thursday and close at 9:43:26 p.m. But NASA managers recently decided to target all station assembly missions for launch at the precise moment the pad is in the station's orbital plane. For Discovery's flight, that works out to 9:38:26 p.m. This "launch-in-plane" strategy minimizes the amount of propellant required and improves the odds of reaching an East Coast runway in the event of a main engine failure early in flight. It also improves the odds of reaching the station if an engine fails to generate full power. The duration of this "preferred" launch window cannot be computed until the shuttle is fueled for flight. But it will last somewhere between two-and-a-half and five minutes. While NASA managers could elect to launch Discovery Thursday at the beginning of its theoretical 10-minute window to provide a bit more time for bad weather to improve, Weems said the nature of the tropical system affecting Florida makes that an unlikely scenario. While the weather is expected to change Thursday, it will change slowly and an additional few minutes likely would not make much difference. Should launch slip to Friday, a different weather system will come into play. A strong cold front is sweeping toward Florida that should reach the area sometime Saturday. Thunderstorms are expected ahead of the front with higher-than-allowable winds behind it. The forecast for Friday calls for a 60 percent chance of acceptable weather while Saturday's outlook calls for a 60 percent chance of "no-go" conditions, primarily due to high winds. "For the launch attempt tomorrow, we'll still have a lot of mid-level and low-level type moisture and the possibility of occasional showers," Weems said. "Should we be delayed into Friday, we have the increased chance of thunderstorms forming in advance of that front. "So we would have a concern over thunderstorms moving from the northwest back into our area. And that would linger right into Saturday. It really depends on the time the front comes through us on Saturday as to what would be the concerns for a Saturday launch." If the front is just to the north of the launch site as forecasters now expect, "then you would have the increased concern on Saturday for thunderstorms," Weems said. "If the front pushes through us, we would have a concern over some increased wind speeds behind the front." =================================================================== Shuttle launch delayed by ET bolt issue, slugghish valve (10/05/00) 12:30 p.m., 10/05/00, Update: Engineers study shuttle fuel tank problem Engineers have held up fueling the shuttle Discovery for launch this evening pending resolution of a last-minute concern about the ship's external fuel tank. NASA managers plan to make a decision about whether to proceed with fueling or to delay the flight within the hour. The problem involves a bolt that retracts during the external tank separation sequence after the shuttle reaches orbit. Analysis of film from a camera aboard Atlantis last month showed one of the bolts in question in that shuttle's external tank failed to fully retract. The concern is that an extended bolt could cause a shuttle to recontact the tank during the separation procedure. Engineers are assessing records and other data to determine the status of the bolts in Discovery's external fuel tank. Launch on the 100th shuttle mission is targeted for 9:38:26 p.m. this evening. Fueling had been scheduled to begin shortly after noon, but the procedure has been held up to give engineers more time to assess the bolt issue. There are no other technical issues of any significance and forecasters are predicting an 80 percent chance of acceptable weather during Discovery's brief launch window. This status report will be updated once a decision has been made one way or the other. 03:15 p.m., 10/05/00, Update: Launch delayed at least 24 hours Launch of shuttle Discovery on a space station assembly mission has been delayed at least one day - and possibly longer - because of concern about a suspect bolt in the ship's external fuel tank. At the same time, engineers are assessing a sluggish valve in Discovery's main propulsion system that is used to help minimize vibrations during ascent due to the flow of propellants. Technicians may be ordered into the shuttle's engine compartment for an inspection or repairs. If so, a launch attempt Friday would not be possible. In the meantime, liftoff of the 100th shuttle mission is tentatively targeted for 9:16:10 p.m. Friday, assuming the valve issue can be resolved and assuming engineers can convince themselves the external tank bolt in question will work properly in orbit. If not, NASA managers could be forced to keep Discovery on the ground for additional analysis or, in a worst-case scenario, roll the shuttle back to the Vehicle Assembly Building for detailed inspections and/or repairs. "We think it's prudent to stand down for a day to give our engineers time to review the data, to reveiw the rationale for flight and to move slowly and with all due concern for this issue," said James Halsell, director of shuttle operations at the Kennedy Space Center. "In other words, we do not was to get 'go' fever, we want to give our people the opportunity to research this potential problem and to understand it fully before we press on." During a routine engineering review of film shot by a camera aboard the shuttle Atlantis during launch last month, engineers noticed that one of the external fuel tank's two aft attachment bolts failed to work properly when the tank was jettisoned. The 14-inch-long 2.5-inch-wide bolts extend from the tank into the shuttle's belly where they are secured with explosive nuts torqued with some 275,000 pounds of force. At tank separation, the nuts are detonated and the bolts are blown down into a housing in the tank. During Atlantis's flight last month, the explosive nut worked properly but the right-side bolt remained extended some two-and-a-quarter inches. The concern is that a hung bolt could remain inside the shuttle attach point long enough for the orbiter to impart forces on the tank, potentially causing it to hit the shuttle. "We do not know, and we have no reason to believe, we have any problems on STS-92," Halsell said. But three teams of engineers are assessing the issue to determine if similar problems have occurred in the past; to re-asses the separation system's basic design; and to determine what, if anythine, would happen should another bolt fail to fully retract. It is not yet known what, if anything, can be done at the launch pad to inspect the bolt in question aboard Discovery or to make repairs if any are required. If the shuttle must be hauled back to the Vehicle Assembly Building, launch likely would be delayed 10 days to two weeks at a minimum. The next major space station milestone is the Oct. 30 launch of the lab's first full-time crew aboard a Russian Soyuz rocket. At least two days are needed between Discovery's landing and the Soyuz launch to give NASA engineers supporting the shuttle flight time to fly to Moscow for the Soyuz mission. NASA presumably could roll Discovery back to the VAB, make inspections or repairs as needed and still launch the 100th shuttle mission in time to support the Soyuz launch on or close to Oct. 30. But at this point, that is little more than idle speculation. This status report will be updated as warranted. In the meantime, the flight plan based on a launch Friday has been posted below, along with a revised ascent timeline. 04:10 p.m., 10/05/00, Update: Details of possible valve repair work Senior NASA managers are scheduled to meet this evening at 9 p.m. to discuss two technical problems affecting the shuttle Discovery's delayed launching. While the 100th shuttle flight is tentatively targeted for liftoff at 9:16:10 p.m. Friday, either issue could prompt an additional delay. One problem involves questions about the performance of a retracting bolt in the shuttle's external fuel tank (see below for complete details). The other issue involves a sluggish valve in the shuttle's propulsion system. If engineers decide to replace the so-called POGO valve, sources say launch would be delayed another three days to Monday at the earliest. They first would have to open the shuttle's engine compartment, remove protective foam, replace the valve, re-foam the assembly and conduct another helium-signature leak test to make sure the propulsion system is tight. This status report will be updated when a decision is made one way or the other. 08:55 p.m., 10/05/00, Update: Shuttle launch delayed to Monday at the earliest Launch of the shuttle Discovery on a space station assembly mission has been delayed to Monday evening at the earliest to replace a sluggish valve in the orbiter's main propulsion system. Concern about a separate issue involving suspect bolts in the shuttle's external tank has not yet been resolved. But assuming the bolt issue can, in fact, be put to rest as expected, engineers are retargeting launch for 8:05 p.m. Monday. NASA only has until Wednesday to get Discovery off the ground before standing down for an already scheduled Atlas rocket launch. While NASA normally will not make more than two back-to-back launch attempts, senior agency managers said this evening they are not ruling out the possibility of making three attempts in a row next week if bad weather or other problems cause additional delays. Work to replace the sluggish POGO vibration-supression valve in the shuttle's aft compartment is a relatively straight forward procedure. Engineers will open up Discovery's engine compartment overnight, remove foam insulation, remove the valve and install a replacement. A mass spectrometer test will then be carried out to make sure the new valve and its connections to the propulsion system are leak free. Normally, a more time-consuming helium-signature leak test would be carried out after such a repair job to verify the integrity of the entire propulsion system. While engineers say such a test is not required in this case, a formal waiver will have to be signed to clear Discovery for launch Monday. The mission flight plan below has been updated to reflect a Monday launch as has the ascent timeline. This status report will be updated as more information becomes available. =================================================================== Valve replacement in work; ET bolt issue remains unresolved (10/06/00) Editor's Note... The following story was written for Spaceflight Now and is reposted here by permission. NASA managers say work to replace a sluggish valve in the shuttle Discovery's engine compartment should be complete by late today, setting the stage for a delayed launch attempt at 8:05 p.m. Monday. But that assumes ongoing work to assess a separate problem - concern about a suspect bolt in the shuttle's external fuel tank - can be resolved by Monday morning. It was that issue that stopped Discovery's countdown just before fueling Thursday and prompted a one-day delay. While backing out of the countdown, engineers noticed sluggish behavior in a 2-inch valve in the orbiter's main propulsion system. The valve was cycled three times and each time, it moved slower than expected. As a result, NASA managers Thursday evening ordered engineers to replace the valve, delaying launch to Monday. "After much, much technical discussion, it was decided the prudent and responsible thing to do was to stand down ... to change out the valve so we could launch with a pristine system," said James Halsell, director of shuttle operations at the Kennedy Space Center. Shuttle launch director Michael Leinbach said engineers opened Discovery's aft engine compartment earlier today. If all goes well, the valve will be replaced by the end of the second shift and leak tested. Normally, such a repair would require a time-consuming helium signature test to make sure the propulsion system remained leak free after the work was complete. But Leinbach said a waiver will be signed to bypass the system-wide helium test in favor of two leak checks focused on the valve and the eight-bolt flange where it is attached. "It does require a waiver. We are breaking into the liquid oxygen system," he said. "But it's a very simple mechanism, a very simple flange construction and we feel very comfortable that a bubble soak leak check and a mass spectrometer leak check around that flange is adequate for this situation." The so-called pogo accumulator recirculation valve is one of two in a system that prevents propellant from surging through the fuel lines during ascent. Without such a shock absorbing system, the shuttle would experience high vibrations during the climb to space. The valve in question is normally opened a few seconds before main engine ignition. Had NASA not stopped the countdown Thursday because of the external tank bolt issue, the flight would have been automatically scrubbed when the countdown computer discovered the problem. "It would normally be opened in the launch countdown at T-minus 12-and-a-half seconds," Halsell said. "If it had improperly worked at that point in time, the computers would have realized it shortly thereafter and would have shut down the count just prior to (engine ignition)." While the valve replacement work is relatively straight forward, Halsell would not speculate on the ultimate outcome of the external tank issue. During analysis of film shot by an automatic camera during the shuttle Atlantis's climb to orbit last month, engineers noticed that one of two huge bolts holding the bottom of the tank to the orbiter failed to retract into the tank properly at tank separation. Engineers are concerned that a hung bolt could remain inside the shuttle attach fitting long enough for the orbiter to impart a force on the tank during separation. If so, the tank could possibly hit and damage the shuttle during the separation sequence. Halsell said three teams of engineers investigating the issue have been given additional time to review past flights, the design of the bolt retraction system and possible workarounds. The teams now are scheduled to report the results of the analysis to senior managers just before fuel loading Monday. "Our current plans," Halsell said, "would be to have a review meeting on Monday morning to understand where they are with their analysis and if they're at a point where they can make the engineering community and also the mission management community feel comfortable that it's safe to go fly." If all goes well, Discovery's countdown will resume at 4:10 a.m. Monday at the T-minus 11-hour mark. The astronauts will be awakened at 7:30 a.m. and NASA managers will meet around 9:10 a.m. to discuss the shuttle's readiness for flight. Engineers will begin pumping a half-million gallons of supercold liquid oxygen and liquid hydrogen rocket fuel into Discovery's external tank around 10:45 a.m. The process will take about three hours to complete. NASA television coverage will begin at 2:30 p.m. The astronauts will suit up and head for pad 39A at 4:15 p.m. and the shuttle's side hatch should be closed and locked for flight by 6 p.m. A 10-minute hold at the T-minus 20-minute mark will begin at 6:50 p.m. and end at 7 p.m. A final 45-minute hold at the T-minus nine-minute mark will begin at 7:11 p.m. Assuming the current launch time - 8:04:58 p.m. - holds up, the countdown will resume at 7:56 p.m. and the 100th shuttle flight will finally be on its way. =================================================================== Bolt issued resolved; shuttle cleared for launch (10/09/00) Editor's Note... The following story was written for Spaceflight Now and is reposted here by permission. NASA managers today cleared the repaired shuttle Discovery for a delayed launch attempt Monday evening to kick off the 100th shuttle flight, the most complex space station assembly mission yet attempted. While forecasters are predicting a 70 percent chance of high crosswinds at the shuttle's 8:05:17 p.m. launch time that could prompt another delay, NASA managers have decided the shuttle's external tank attachment bolts are healthy and good to go as is. Discovery's planned launch last Thursday was delayed just before fueling when engineers reviewing film from a flight last month noticed one of the two external tank aft attach bolts protruding about two-and-a-quarter inches after the tank was jettisoned. It should have retracted all the way into a protective housing when the explosive nut on the bolt detonated to begin the tank separation sequence. An analysis of film from previous shuttle flights has turned up several instances where an aft attach bolt has failed to fully retract into its housing. The concern is that the shuttle could impart a load, or force, on an extended bolt as separation begins, causing the tank to pitch, roll or yaw in such a fashion that it could hit and damage the orbiter. "They have seen a number of times that this has occurred in the past, on the order of a half-dozen or so," NASA test director Steve Altemus told reporters today. "There's never been any (damage) associated with that at all." After studying the issue over the weekend, engineers concluded the bolt issue poses no threat to flight safety. The only case in which an extended bolt could be a factor, they concluded, was during a return-to-launch-site abort or a trans-Atlantic abort to Spain or Africa. During such an abort, the shuttle would be positioned atop the tank during the separation sequence. If the shuttle's main flight computers failed, forcing the crew to rely on a backup flight computer, the tank separation sequence would occur a bit slower than usual, allowing more time for recontact to occur. But such a series of failures is unlikely and Discovery was cleared for launch as is. NASA initially ordered a minimum 24-hour launch delay for Discovery to assess the bolt issue. But the flight was delayed again Thursday night, this time to 8:05:17 p.m. Monday, after NASA managers ordered engineers to replace a sluggish valve in the shuttle's engine compartment that helps minimize vibrations during ascent due to propellant surges. Engineers noticed the problem while they were recycling the countdown for a possible Friday launch. Had NASA pressed ahead with launch Thursday, the sluggish valve would have prompted on-board computers to stop the countdown just before main engine ignition. In any case, the valve has now been replaced and Altemus said Discovery is once again ready for launch on the 100th shuttle mission. "While the program managers continue to evaluate and come to closure on the ET separation bolt issue, the launch team continues to prepare the vehicle and all systems for launch on Monday evening," he said. "The bird is in great shape We're not working any technical issues whatsoever and the ground systems are performing as well." But the weather remains a wild card. John Weems, shuttle weather officer with the 45th Weather Squadron at the Cape Canaveral Air Force Station, said high winds in the wake of a passing cold front will cause problems. "The main concern will be the winds behind this front," he said. "They will be from about 350 to 020 degrees. The farther east these winds become, the more likely they'll violate the RTLS crosswind constraint of 15 knots." During the first few minutes of flight, a main engine failure could force a crew to attempt a risky return to launch site abort, known as an RTLS, to the Kennedy Space Center. Flight rules forbid launching a shuttle if the predicted crosswinds at the shuttle runway are higher than 15 knots in daylight or at night. A 12-knot landing limit is used for normal night landings at the end of a mission. The shuttle runway runs from northwest to southeast, i.e., 330 degrees to 150 degrees. Winds from 60 degrees or 240 degrees are pure crosswind. For other angles, the crosswind component is less. For Discovery's launching, forecasters are predicting winds from 350 degrees to 20 degrees, resulting in a crosswind right at NASA's limit. "To give you an idea of how critical (wind direction) can be, if the winds are from 360 degrees, you would have to have about 29 knots peak to violate that 15-knot crosswind component," Weems said. "If they swing around to around 010 degrees, that peak speed limit drops to about 24 knots and the further east it goes, the less wind it takes to violate that crosswind components." Weems said computer models tend to err on the side of predicting winds from a more northeasterly direction than what is actually observed. "If we're incorrect even by 10 degrees in that quadrant, it really buys us a significant amount of wind," he said. In the meantime, the official forecast calls for a 70 percent chance of high enough winds to cause a delay. The outlook is the same for Tuesday night, but conditions are expected to improve dramtically by Wednesday, resulting in a 70 percent "go" forecast. NASA must get Discovery off the ground by Wednesday or launch will be delayed to at least Oct. 14 because of an already scheduled Atlas rocket launch from the Cape Canaveral Air Force Station. NASA normally makes two back-to-back attempts to launch a shuttle before standing down 24 hours to give the launch team a chance to rest. But Altemus said NASA managers could waive that rule and make three attempts in a row next week if necessary. =================================================================== Launch delayed 24 hours by high winds (10/09/00) 09:00 a.m., 10/09/00, Update: Launch delayed 24 hours by high winds NASA managers decided today to delay the shuttle Discovery's launch on a space station assembly flight by another 24 hours because of high winds that prevented engineers from completing preparations for fueling. Launch of the 100th shuttle flight is now targeted for 7:40 p.m. Tuesday, but forecasters expect more bad weather that could prompt yet another delay. Discovery was grounded last Thursday because of concern about suspect bolts in the ship's external tank attachment system. Launch initially was delayed 24 hours to allow time for a hurried engineering review. But Thursday night, the flight was delayed to Monday after engineers discovered a sluggish valve in the shuttle's engine compartment. The valve was replaced over the weekend and the bolt issue was resolved Sunday. But high winds behind a cold front that swept through central Florida Saturday and Sunday prompted forecasters to predict a 70 percent chance of another launch delay due to high crosswinds at the shuttle's emergency runway. The launch team pressed ahead nonetheless, shooting for a launch at 8:05:17 p.m. But early this morning, the winds at pad 39A were so high engineers were unable to move a gaseous oxygen vent arm into position over the tip of the external tank in time to support fueling. As a result, NASA's mission management team ordered a 24-hour scrub at 9 a.m. This status report will be updated as warranted. An updated flight plan and ascent timeline will be posted below shortly. 11:30 a.m., 10/09/00, Update: Shuttle launch strategy outlined Editor's Note... The following story was written for Spaceflight Now and is posted here by permission. After weekend work to resolve two technical issues, the hard-luck shuttle Discovery was grounded again today, this time by high winds at the launch pad that prevented engineers from completing preparations to fuel the ship for take off. Launch of the 100th shuttle flight, the most complex space station assembly mission yet attempted, is now targeted for 7:40 p.m. Tuesday, weather permitting. Forecasters with the 45th Space Wing at the Cape Canaveral Air Force Station are predicting a 70 percent chance of low clouds and high winds Tuesday evening that could prompt yet another delay. Conditions are expected to improve dramatically by Wednesday, with a 70 percent chance of acceptable conditions. NASA typically makes two back-to-back launch attempts before standing down a day to give engineers time to rest. But agency managers said three attempts in a row might be considered, depending on the weather and other factors. NASA initially had until Wednesday to get Discovery off the ground before standing down until Oct. 14 to make way for the Oct. 12 launch of an Atlas rocket carrying an Air Force satellite. Shuttles and unmanned rockets launched from the Cape Canaveral Air Force Station share the same military tracking systems and it takes a day or more to reconfigure the Eastern Range to support a different mission. Early today, Lockheed Martin officials delayed the Atlas flight to late next week because of a technical problem, giving NASA additional options for getting Discovery off the ground this week. The current strategy, NASA officials said, is to press ahead for a launch try Tuesday and again Wednesday, if necessary. At that point, the team could either stand down a day and try again Friday or press ahead for a third-straight launch attempt Thursday. Today's scrub was ordered after engineers were unable to move a rotating gaseous oxygen vent hood into position over the tip of Discovery's external fuel tank. The so-called "beanie cap" is used to carry oxygen vapor away from the tank after it is loaded with supercold propellants to prevent potentially dangerous ice from building up. It is rotated away from the tank two minutes and 55 seconds before launch. The beany cap normally would have been moved into place by 2 a.m. or so, but high winds at the pad in the wake of a weekend cold front made that impossible. Gusts as high as 44.6 knots were recorded, violating NASA's 42-knot safety limit. Had the arm been in place by 5 a.m., fueling could have started on time. But by 8 a.m., time had run out for even a delayed fueling start and one hour later, NASA's mission management team ordered the 24-hour delay. Discovery's launch flow is shaping up to be one of the most difficult in recent memory. An attempt to get the spaceship into orbit last Thursday was delayed a minimum of 24 hours because of concern about the status of critical bolts used to hold the external tank to the shuttle. Later that night, engineers decided a sluggish valve in Discovery's engine compartment needed to be replaced and launch was delayed an additional two days to Monday. A new valve was installed over the weekend and on Sunday, mission managers decided the external tank attachment bolts were safe to launch as is, leaving weather the only concern. NASA needs to get Discovery off the ground as soon as possible to attach a new shuttle docking port to the international space station and an 18,300-pound truss that houses four stabilizing gyroscopes. The Z1 truss also will serve as a temporary mounting point for a huge solar array scheduled for delivery in December. The space station's first full-time crew is scheduled for launch atop a Soyuz rocket on Oct. 30. Discovery must be back on the ground at least two days before the Soyuz takes off to give NASA personnel supporting both missions time to fly to Russia. The station crew needs the Z1 and the new solar array to provide additional power. The truss will be mounted atop the U.S. Unity module. But the gyroscopes will not be activated until early next year, after arrival of the U.S. laboratory module Destiny. To keep the gyros from getting too cold between now and the end of the year, the station will be oriented to provide additional solar heating. As a result, the Unity module will be too warm for the station crew to enter until the solar arrays scheduled for attachment in December are in place and providing the electricity needed to power heaters on the gyroscopes. =================================================================== Shuttle launch delayed by debris on external tank (10/10/00) 08:15 a.m., 10/10/00, Update: Shuttle set for fueling, third launch try Engineers are gearing up to load the shuttle Discovery's external tank with rocket fuel today, weather permitting, for a thrice delayed launch this evening on an ambitious space station assembly mission. With forecasters continuing to predict a 70 percent chance of high winds and low clouds that could prompt a fourth delay, Discovery is scheduled for liftoff from pad 39A at 7:39:36 p.m. As with all space station assembly missions, the exact launch time will not be set until shortly before launch based on final radar tracking of the international space station. While this is Discovery's third launch date, it will be the first time the ship has actually been loaded with rocket fuel. Last Thursday, the countdown was called off before fueling started because of concern about the health of explosive bolts used to attach the ship's external fuel tank. NASA managers initially ordered a minimum 24-hour delay to Friday. Later that evening, however, the flight was delayed an additional two days to Monday when engineers decided a sluggish valve in Discovery's engine compartment needed to be replaced. The repair work was carried out over the weekend and on Sunday, the external tank bolt issue was resolved, setting the stage for a launch attempt Monday evening. But high winds in the wake of a weekend cold front prevented engineers from completing fueling preparations and the flight was delayed an additional 24 hours. While the forecast remains bleak for this evening, engineers were at least able to position a gaseous oxygen vent hood - the so-called beanie cap - over the tip of Discovery's external fuel tank this morning, a pre-fueling step they were unable to complete Monday. NASA's mission management team will meet at 9:45 a.m. to assess the weather and the team's launch readiness. This status report will be updated as soon as possible thereafter. 10:45 a.m., 10/10/00, Update: Discovery cleared for fueling NASA managers have cleared the Kennedy Space Center launch team to begin fueling the shuttle Discovery for a launch attempt at 7:40 p.m. That's assuming engineers can resolve an apparent problem in Discovery's mobile launch platform involving a circuit in a system used to fire various explosive devices during launch and ascent. Fueling had been scheduled to begin at 10:45 a.m., but the procedure currently is on hold. NASA spokesman George Diller said engineers are not sure the system in question actually has a problem. But they decided to check it out before fueling starts to facilitate any repairs that might be necessary. Fueling must begin by around 12:15 p.m. to permit a launch this evening. Forecasters, meanwhile, continue to predict a 70 percent chance of high crosswinds and low clouds that could prompt yet another launch delay. 01:00 p.m., 10/10/00, Update: Shuttle fueling underway; weather remains an issue Editor's Note... The following story was written for Spaceflight Now and is reposted here by permission. After three frustrating launch delays - and a last-minute snag today - engineers finally began fueling the shuttle Discovery for blastoff today on the 100th shuttle mission, the most complex space station assembly flight yet attempted. While Discovery appears ready to go, forecasters are predicting a 70 percent chance of low clouds and high crosswinds at the shuttle's emergency runway that could prompt yet another delay. NASA flight rules prohibit shuttle launches if crosswinds at the 3-mile-long runway are predicted to exceed 15 knots a half-hour or so after liftoff. That's when a shuttle crew would be attempting an emergency landing if one of the ship's three main engines failed during the first two minutes and 16 seconds of flight. An engine failure after that would result in a landing in Europe or in an abort to a lower-than-planned orbit. Forecasters at the Spaceflight Meteorology Group at NASA's Johnson Space Center in Houston are predicting crosswinds this evening from 40 degrees at 10 to 18 knots. Winds from 60 degrees make up a direct crosswind at the shuttle runway, so the expected winds will be right at NASA's limit. Hoping for the best, engineers began pumping a half-million gallons of rocket fuel into Discovery's external fuel tank at 12:02 p.m. The procedure was held up an hour and 17 minutes because of last-minute troubleshooting to resolve questions about the status of a circuit breaker in the shuttle's mobile launch platform. The circuit in question is part of a system that fires explosive charges to disconnect and pull away various data, electrical, fluid and gas lines attached to the tail of the orbiter at liftoff. A team of engineers was dispatched to the launch pad to resolve the issue and they were able to reset the circuit breaker just before time ran out for fueling. A subsequent test from the firing room confirmed the system was ready for launch. Fueling should be complete by 3 p.m. or so, 45 minutes before the countdown resumes after a built-in two-hour hold. Discovery's crew - commander Brian Duffy, pilot Pamela Melroy, Japanese astronaut Koichi Wakata and spacewalkers Leroy Chiao, William McArthur, Peter "Jeff" Wisoff and Michael Lopez-Alegria - is scheduled to begin strapping in around 4:20 p.m. to await liftoff. As with all space station assembly missions, Discovery's exact launch time will not be set until shortly before launch based on final radar tracking of the international space station. The launch will be timed to coincide with the moment Earth's rotation carries pad 39A - and the space shuttle - into the plane of the space station's orbit. Launching into the orbital plane minimizes the propellant required to reach the target. But it also reduces the duration of the launch window. While the shuttle can, in theory, reach the station if it launches within five minutes of the moment the pad is "in plane" with the station's orbit, Discovery's window will last just two-and-a-half to five minutes. The exact duration will be computed later this afternoon. Assuming an on-time liftoff, Discovery will dock with the space station at 2:44 p.m. on Oct. 12. The goal of the mission is to install a new shuttle docking port on the orbital outpost and to attach an 18,300-pound truss to the U.S. Unity module that will serve as a temporary mounting point for a huge set of solar arrays scheduled for installation in December. The Z1 truss also houses four stabilizing gyroscopes and the station's main KU-band and S-band communications antennas. Four back-to-back spacewalks will be required to hook up the new components and to position the antennas. If all goes well, Discovery will undock from the station at 10:38 a.m. on Oct. 19 and land back at the Kennedy Space Center at 3:12 p.m. on Oct. 21. But those times are pre-flight predictions that could be affected by a variety of factors, including the possibility the crew could be asked to enter the Russian Zvezda command module to troubleshoot problems with two of its eight batteries. Whether that would require a mission extension or not is not yet known. 03:00 p.m., 10/10/00, Update: Forecast improves to 50-50; fueling complete After a late start, engineers are topping off the shuttle Discovery's external fuel tank and forecasters say conditions are improving for a launch attempt at 7:40 p.m. While meteorologists initially predicted a 70 percent chance of high winds and low clouds that could prompt a fourth launch delay, the odds have now improved to 50-50. Otherwise, there are no technical problems of any significance at pad 39A and Discovery's seven-member crew plans to begin strapping in around 4:20 p.m. 04:15 p.m., 10/10/00, Update: Astronauts begin boarding shuttle The Discovery astronauts began boarding the shuttle Discovery today at 4:15 p.m. There are no technical problems at the launch pad and forecasters continue to hold out hope that conditions will permit an on-time liftoff at 7:40 p.m. 05:45 p.m., 10/10/00, Update: Engineers assess launch pad debris issue Forecasters have upgraded the outlook for tonight's shuttle launch to 70 percent "go." But the 100th shuttle flight could be in doubt because of an eight-ounce metal pin that appears to be resting loose on the liquid oxygen line leading from the ship's external tank into the orbiter. The pin apparently came from an access platform erected earlier in the launch processing flow that has since disassembled. Wherever the debris came from, engineers cannot reach it at the pad this evening in time for launch at 7:40 p.m. The concern is the metal pin will fly off during launch and either hit the orbiter directly or indirectly after bouncing off launch pad structure. There is no word yet how the issue might be resolved, but it is doubtful NASA managers will commit Discovery to launch unless they can convince themselves the pin is harmless. And that might be difficult to do. 06:35 p.m., 10/10/00, Update: Launch delayed to Wednesday by debris on shuttle With an improving forecast and no technical issues, NASA managers reluctantly ordered a fourth launch delay for shuttle Discovery this evening after discovering a metal pin lodged in an inaccessible area at the base of the ship's external fuel tank. How the eight-ounce metal pin got on the strut between the shuttle and the tank is not known, but engineers were concerned it could fly free during ascent and possibly hit the spacecraft with catastrophic results. "The mission mangement team has been reviewing the pip pin problem on the external tank and has concluded that we just can't get comfortable with the pin in place," said launch director Michael Leinbach. "So we have determined that we will scrub for the day. I'd like to set up for a 24-hour scrub turnaround." While the pin was visible to an ice and debris inspection team sent to the pad shortly after fueling was complete, they had no way to reach the area - 40 feet above the pad deck - without special access platforms. The pin apparently came from such a platform that was erected between the external tank and the space shuttle earlier in Discovery's launch processing flow. The platform later was disassembled. Somehow, the pin ended up wedged in the main strut area where liquid oxygen is fed into the belly of the space shuttle. At issue was the kind of damage that might result if the pin fell off at launch or later in the ascent. At velocities below about Mach 2.5 - two-and-a-half times the speed of sound - a quick analysis indicated the pin likely would move toward the external tank's aft dome. At speeds higher than Mach 2.5, the pin likely would move back toward the orbiter's body flap area. If the pin fell off during engine ignition, it possibly could bounce off the mobile launch platform and hit the orbiter, tank or boosters. Engineers discussed using high-pressure water or air lines hoses to dislodge the pin, but in the end decided against either option. And with just a three-and-a-half-minute launch window, there was no time to erect a platform or ladders to reach the debris in time for Discovery's planned 7:40 p.m. liftoff. As a result, Leinbach had no choice but to call off the countdown and to tentatively reschedule Discovery for a fifth launch try Wednesday at 7:17 p.m. Forecasters are predicting a 60 percent chance of acceptable conditions Wednesday evening. This status report will be updated as more information becomes available. 09:50 p.m., 10/10/00, Update: Shuttle managers 'disconcerted' by launch scrub Editor's Note... The following story was written for Spaceflight Now and is posted below by permission. Clearly frustrated, NASA managers today ordered a fourth launch delay for the hard-luck shuttle Discovery after engineers spotted a small but potentially dangerous metal pin lodged in an inaccessible area at the base of the ship's external fuel tank. How the eight-ounce "pip pin," used to secure tools and access platforms at the launch pad, got lodged in the strut between the shuttle and the external tank is not yet known. But engineers were worried it could have fallen free during ascent, possibly hitting the spacecraft with catastrophic results. "We tried to analyze to the best of our ability where the pip pin would go," said shuttle program manager Ronald Dittemore. "And after all the talking and the meetings were over, we came to the conclusion that we just didn't have a good handle on where this thing would fall. "The damage to an engine or the body flap could be severe and because we did not want to take that risk, we decided to scrub today and go retrieve the pip pin." As a result, launch of a fully fueled 4.5-million-pound spacecraft was blocked by an eight-ounce piece of debris that Dittemore said should have been spotted earlier. "It's disconcerting to all of us that we didn't spot it until T-minus three hours," he said. "So we're going to go back and look at our inspection points, we're going to look at how we do them and when we do them." The scrub was particularly frustrating because after three previous delays and an initially bleak forecast today, the weather had improved dramatically and launch managers were optimistic about finally getting the 100th shuttle flight off the ground. But it was not to be. Launch director Michael Leinbach officially called off the countdown at 6:30 p.m. and re-targeted launch for 7:17 p.m. Wednesday. Forecasters are calling for a 60 percent chance of acceptable conditions Wednesday evening. Discovery's crew - commander Brian Duffy, pilot Pamela Melroy, Japanese robot arm operator Koichi Wakata and spacewalkers Leroy Chiao, William McArthur, Peter "Jeff" Wisoff and Michael Lopez-Alegria - took the delay in stride and climbed out of the orbiter around 7 p.m. The offending pip pin was noticed earlier today by a technician using binoculars during a routine post-fueling ice and debris inspection. While the pin was clearly visible, the inspection team had no way to reach the area - 40 feet above the pad deck - without special access platforms. Such pins are "used all over the pad in many, many locations," said David King, a senior shuttle manager at the Kennedy Space Center. "We obviously don't know exactly where this particular one came from. We will be doing an inventory to figure that out." After draining the shuttle's half-million-gallon load of oxygen and hydrogen rocket fuel, engineers will move a rotating service gantry back in place around the shuttle to gain access to the area where the pip pin is located. Once it is removed, the area will be examined for any damage and the launch team will prepare Discovery for its fourth launch try. While the pin and a 12-inch long section of plastic-wrapped tether did not appear particularly threatening, engineers could not predict what might happen if it fell off at launch or later in the ascent. If the pin fell off during engine ignition, it possibly could bounce off the shuttle's mobile launch platform and hit one of the orbiter's engines, the tank or boosters. "In this particular instance, we could not get comfortable with the fact that it would fall to the deck and not represent some risk of rebounding back up into an engine," Dittemore said. "And impact to an engine or a critical part of the orbiter would not be a good day." And even if the pin stayed in place during the engine start sequence, there was no way to predict what might happen if it fell off later. A quick analysis indicated the pin likely would move toward the external tank's aft dome at velocities below about Mach 2.5 - two-and-a-half times the speed of sound. At speeds higher than Mach 2.5, the analysis indicated the pin likely would move back toward the orbiter's body flap area. Engineers discussed using high-pressure water or compressed air to dislodge the pin, but in the end decided against either option. And with just a three-and-a-half-minute launch window, there was no time to erect a platform or ladders to reach the debris in time for Discovery's planned 7:40 p.m. liftoff. As a result, Leinbach had no choice but to call off the countdown. While King and Dittemore agreed the scrub was probably due to human error, both refused to place any blame. Yet. "We could have a hole in our process, too," King said. "You cannot point the finger at any individual. "What we try to do here is we try to put processes in place that will allow us multiple opportunities to find these kinds of things and for some reason, this one got through at least one inspection that we probably should have found it prior to this one. But even that's speculation at this point." Said Dittemore, "Certainly, I'm not pleased to get this late in the count and find out we have a tool resting on a critical area in our orbiter, in our stack. So I'm disappointed in that sense." "On the positive side," he said, "our inspection team spotted this problem. That is a very thorough inspection at T-minus three hours and perhaps we need to have the same folks do it earlier. I'm not sure yet." The goal of the 100th shuttle mission is to install a new docking port on the space station and to attach an 18,300-pound truss to the U.S. Unity module that will serve as a temporary mounting point for a huge set of solar arrays scheduled for installation in December. The Z1 truss also houses four stabilizing gyroscopes and the station's main KU-band and S-band communications antennas. Operating Discovery's 50-foot-long robot arm, Wakata plans to mount the truss atop the Unity module Friday afternoon. That will set the stage for four back-to-back spacewalks Saturday through Tuesday to electrically hook up the Z1 truss and pressurized mating adapter No. 3, which will serve as an alternate docking port for upcoming assembly flights. =================================================================== Shuttle Discovery rockets into orbit (10/11/00) 09:15 a.m., 10/11/00, Update: NASA gears up for fifth launch try NASA engineers retrieved a potentially dangerous locking pin from the shuttle Discovery's external fuel tank and are gearing up to make a fifth launch attempt this evening at 7:17 p.m. Forecasters are predicting a 60 percent chance of acceptable weather, with the primary concerns being low clouds, high crosswinds and a chance of rain showers in the launch area. 10:30 a.m., 10/11/00, Update: NASA 'go' for fueling; engineers assess tape issue NASA managers have given engineers permission to begin refueling the shuttle Discovery today for a launch attempt at 7:17 p.m. Forecasters are predicting a 60 percent chance of favorable weather. A launch attempt Tuesday was scuttled after engineers noticed a potentially dangerous locking pin resting loose on a strut at the bottom of the shuttle's external tank. The pin was removed today around 2 a.m. The only other technical issue being discussed this morning is a bit of tape, possibly from an earlier repair, on a heat-shield tile near one of the shuttle's external tank umbilical doors. The start of fueling was held up to give engineers more time to photograph the area for later analysis. But this does not appear to be a major issue. At this point, anyway. Here is the remainder of today's countdown timeline: 09:22 a.m....Begin a one-hour built-in hold at T-minus six hours 10:22 a.m....The countdown resumes at the T-minus six-hour mark 10:22 a.m....Shuttle fueling begins (likely to begin earlier) 01:22 p.m....Shuttle fueling is complete 01:22 p.m....Begin a two-hour built-in hold at T-minus three hours 01:30 p.m....NASA television coverage begins 02:17 p.m....Crew snack/photo opportunity 02:47 p.m....Crew weather briefing 02:57 p.m....Astronauts begin donning pressure suits 03:22 p.m....The countdown resumes at T-minus three hours 03:27 p.m....The astronauts leave crew quarters 03:57 p.m....Astronauts arrive at launch pad white room 05:12 p.m....Shuttle hatch closed and latched 06:02 p.m....Begin a 10-minute hold at T-minus 20 minutes 06:12 p.m....The countdown resumes 06:23 p.m....Begin a 45-minute hold at T-minus nine minutes 07:08 p.m....The countdown resumes at T-minus nine minutes 07:12 p.m....Hydraulic power system start at T-minus five minutes 07:17 p.m....Launch of shuttle mission STS-92 07:26 p.m....Main engine cutoff 08:01 p.m....OMS-2 rocket firing to circularize orbit 11:00 a.m., 10/11/00, Update: Shuttle fueling underway Engineers began refueling the shuttle Discovery today around 10:40 a.m., setting the stage for a launch attempt at 7:17 p.m. Fueling should be complete by 1:40 p.m. 02:15 p.m., 10/11/00, Update: Shuttle fueled for launch Engineers finished loading the shuttle Discovery's external tank with a half-million gallons of supercold liquid oxygen and hydrogen rocket fuel at 1:30 p.m. The tank will be continuously topped off through the remainder of the countdown to replace any oxygen and hydrogen that boils off between now and launch. There are no technical problems of any significance at pad 39A. The shuttle's seven crew members plan to begin strapping in around 4 p.m. to await liftoff at 7:17 p.m. Forecasters continue to predict a 60 percent chance of acceptable weather. The primary concern is for crosswinds higher than 15 knots at the shuttle's emergency runway. While dark clouds are presently passing through the Cape area, meteorologists say the sky should clear as the day wears on. NASA flight controllers have updated the shuttle's launch windows through Oct. 17. Here are the latest numbers (in Eastern time): DATE.....Window Open.....Launch..........Window Close....Rendezvous 10/11....07:12:00 p.m....07:17:00 p.m....07:22:00 p.m....FD-3 10/12....06:49:25 p.m....06:54:25 p.m....06:59:25 p.m....FD-4 10/13....06:23:43 p.m....06:28:42 p.m....06:33:42 p.m....FD-3 10/14....06:01:07 p.m....06:06:06 p.m....06:11:06 p.m....FD-3 10/15....05:38:32 p.m....05:43:32 p.m....05:48:31 p.m....FD-4 10/16....05:12:50 p.m....05:17:50 p.m....05:22:49 p.m....FD-3 10/17....04:50:14 p.m....04:55:14 p.m....05:00:13 p.m....FD-4 03:00 p.m., 10/11/00, Update: Forecasters say winds OK; concerned about clouds and rain Meteorologists with the 45th Weather Squadron at the Cape Canaveral Air Force Station have amended the forecast for this evening's launch of the shuttle Discovery, shifting concern from high winds to the possibility of low clouds and rain. Crosswinds at the shuttle's emergency runway are now expected to be below NASA's 15-knot safety limit. But forecasters say a broken deck of clouds could develop at 4,000 feet - NASA's limit is 5,000 feet - and rain showers are possible within 20 nautical miles. Even so, forecasters continue to predict a 60 percent chance that conditions will be acceptable for launch this evening at 7:17 p.m. Discovery's crew, meanwhile - commander Brian Duffy, pilot Pamela Melroy, Japanese robot arm operator Koichi Wakata and spacewalkers Leroy Chiao, William McArthur, Peter "Jeff" Wisoff and Michael Lopez-Alegria - began donning their pressure suits shortly before 3 p.m. The astronauts are scheduled to head for pad 39A shortly to strap in for launch on the 100th shuttle mission. As reported earlier, there are no technical problems of any significance at this point that would prevent an on-time liftoff. 03:55 p.m., 10/11/00, Update: Astronauts begins strapping in for launch The Discovery astronauts began strapping into the space shuttle at 3:50 p.m., led by commander Brian Duffy and spacewalker Leroy Chiao. All seven crew members are expected to be in place and the shuttle's side hatch closed for flight by 5:12 p.m. Engineers are not tracking any technical issues and the weather remains the only concern for a launch attempt at 7:17 p.m. 05:25 p.m., 10/11/00, Update: Weather now 80 percent 'go' Forecasters with the 45th Weather Squadron at the Cape Canaveral Air Force Station have improved the odds for getting the shuttle Discovery off the ground this evening to 80 percent "go." Clouds over the Cape are breaking up and crosswinds at the shuttle's emergency runway are expected to be below NASA's 15-knot crosswind limit. The astronauts are strapped in and the shuttle's hatch is closed and locked for flight. Liftoff remains targeted for 7:17 p.m. There are no technical problems of any significance at pad 39A. 06:22 p.m., 10/11/00, Update: Weather improves; NASA changes hold durations to fix firing room computer console The shuttle Discovery's countdown was held up briefly at T-minus 20-minute mark because of problems with a control console in the launch control room. Engineers configured a backup console to take over the load and the countdown resumed at 6:21 p.m. The unplanned extension of a hold at the T-minus 20-minute mark should not have any impact on Discovery's planned 7:17 p.m. launch time. A final 45-minute hold at the T-minus nine-minute mark will be adjusted to make up the lost time. The weather, meanwhile, continues to look favorable for an on-time launch with rain showers moving out of the area and the clouds going from broken to widely scattered. 07:08 p.m., 10/11/00, Update: Terminal countdown begins; launch on tap at 7:17 p.m. The shuttle Discovery's countdown has picked up at the T-minus nine-minute mark, setting up a launch attempt at 7:17:00 p.m. The launch window will close at 7:21:12 p.m. "The crew of Discovery wants to thank everybody for getting us here and we are ready to go," commander Brian Duffy told mission managers. "OK, Brian," replied launch director Michael Leinbach. "All good things are worth waiting for and I think you and your crew have waited long enough for this one. So good luck on this extremely important mission to the international space station and have fun." "Thanks, Mike," Duffy called. "Once again, thanks to all of your team and to all the folks around the world that have gotten this mission ready. The crew's looking forward to it and we're going to go take a big step here. Let's go." This status report will be updated after Discovery takes off or as conditions warrant. 07:30 p.m., 10/11/00, Update: Shuttle Discovery rockets into orbit Editor's Note... The following story was written for Spaceflight Now and is reposted here by permission. After a string of frustrating launch delays, the shuttle Discovery finally rocketed into orbit today to kick off the 100th shuttle mission, the most complex space station assembly flight yet attempted. With commander Brian Duffy and rookie pilot Pamela Melroy at the controls, Discovery's twin solid-fuel boosters ignited with a crackling roar at 7:17 p.m., instantly pushing the 4.5-million-pound spaceship skyward. "...three, two, one, booster ignition and liftoff of Discovery, making shuttle history and building our future in space," said launch commentator Joel Wells as Discovery roared to life. Putting on a spectacular sky show, the shuttle majestically climbed above its launch gantry, wheeled about to line up on the proper trajectory and arced away to the northeast, hot on the trail of the international space station. Launch occurred at the moment Earth's rotation carried pad 39A into the plane of the space station's orbit. The unmanned station complex was sailing 230 miles above the southern Indian Ocean at the moment the shuttle thundered aloft. It will take Duffy and company two days to chase down their quarry for a carefully choreographed docking Friday afternoon as the two spacecraft pass over Russian ground stations. Joining Duffy and Melroy aboard the shuttle are Japanese robot arm operator Koichi Wakata and spacewalkers Leroy Chiao, William McArthur, Peter "Jeff" Wisoff and Michael Lopez-Alegria. Melroy is the only rookie on the roster. "Pam, welcome to space and congratulations," astronaut Dominic Gorie called from mission control in Houston after the shuttle slipped into orbit. "Thanks, Dom, it was beautiful!" Melroy replied. The goal of mission STS-92 is to attach a new $20 million shuttle docking port and a $273 million truss that will serve as the mounting point for a huge set of solar arrays scheduled for deliver in December. Other equipment on board pushes the total cost of Discovery's payload to around $300 million. Four back-to-back spacewalks by alternating two-man teams will be required to electrically connect the new components, to hook up coolant lines and to position the station's main KU-band and S-band radio antennas. With today's on-time liftoff, Discovery will dock with the station around 1:43 p.m. Friday. Wakata then plans to mount the Z1 truss atop the U.S. Unity module around 11:02 a.m. Saturday. The first of the four back-to-back spacewalks is scheduled to begin at 10:32 a.m. Sunday. If all goes well, Discovery will undock from the station around 9:37 a.m. on Oct. 20 and land back at the Kennedy Space Center at 2:10 p.m. on Oct. 22. Just eight days later, the space station's first full-time crew - commander William Shepherd, Yuri Gidzenko and Sergei Krikalev - is scheduled for launch aboard a Russian Soyuz rocket. NASA plans to close out the year by attaching a huge set of electricity producing solar arrays to the station in early December that will ease an on-going power shortage aboard the outpost. Two of the Russian command module Zvezda's eight batteries are not working properly. While the module can operate in a powered-down mode with as few as three, NASA considers five the bare minimum to support a full-time crew. Station controllers are discussing the possibility of having Discovery's crew enter the module for an impromptu inspection to gain insight into what might be wrong with batteries 4 and 5. But he astronauts are not trained to service Zvezda's batteries and there is little they could do beyond inspecting connectors to make sure there are no obvious wiring problems. Should additional batteries fail between now and the end of the month, station managers likely would re-assess the wisdom of launching Shepherd's crew on Oct. 30 as currently planned. In that case, NASA managers would consider launching the solar arrays first to provide a more comfortable power margin. But at this point, no such decisions have been made. NASA originally hoped to launch Discovery last Thursday, but the flight has been repeatedly delayed by technical problems, bad weather and, on Tuesday, because of an oversight by ground crews. Discovery was already fueled for takeoff Tuesday when an inspection team noticed an eight-ounce metal locking pint lodged in an inaccessible area at the base of the shuttle's external tank. Such tethered "pip pins" are used to secure tools and access platforms at the pad and it's not yet known how this one made its way onto the external tank. Officials said it should have been spotted earlier, but technicians did not find it until the T-minus three-hour mark. Worried the pin could fall free during ascent and damage a critical system, shuttle managers reluctantly ordered a 24-hour launch delay so a rotating gantry could be put back in place to give technicians access to the area. Around 2 a.m. today, technicians finally reached the offending pip pin and removed it, setting the stage for a fifth launch attempt this evening. If the flight is delayed again for any reason, shuttle managers likely would stand down until Friday to top off the ship's on-board supplies of liquid hydrogen and oxygen, which are used to power the shuttle's electrical generators. A launch try Thursday would require a flight-day four rendezvous with the space station while launch tries Friday and Saturday would result in dockings on the third day of the mission. That is NASA's preferred option to maximize the time available to the crew to complete its work. 12:30 a.m., 10/12/00, Update: Astronauts downlink dramatic launch video The Discovery astronauts late this evening downlinked dramatic video from inside the cockpit of the space shuttle, showing the jerking and shaking of launch and a dramatic light show produced by the ship's main engine exhaust plume as the spacecraft left the atmosphere. The camera was positioned at the back of Discovery's upper flight deck, looking forward over the shoulders of flight engineer William McArthur and, to his right, Japanese astronaut Koichi Wakata. in front of them were commander Brian Duffy in the forward left seat and rookie pilot Pamela Melroy in the front right seat. Discovery's three main engines began firing up 6.6 seconds before liftoff, shaking the crew with obvious power as they throttled up. At 7:17 p.m., the shuttle's two solid-fuel boosters ignited, pushing Discovery skyward and jerking the astronauts about with obvious force. "In the scene there, you can see the boosters light and right before that, you can see engine start with sort of a high-frequency, low-amplitude vibration," Duffy narrated. "We were all impressed with the ride uphill." Two minutes and five seconds after liftoff, Discovery's two solid-fuel boosters were jettisoned, pushed away by small rocket motors that produced a brilliant flash in the shuttle's cockpit windows. "And pretty clearly there you can see the boosters come off," Duffy commented. Three minutes and 42 seconds after liftoff, Duffy could be seen reaching across a central instrument console with his right hand to shake Melroy's left. "Of course, Mario, you can see there Pam at that moment was the greatest pilot anybody had ever seen as she became our newest astronaut," McArthur radioed astronaut Mario Runco in mission control. "Roger that, Bill, concur completely," Runco replied. As Discovery climbed out of Earth's atmosphere, the plume from the shuttle's three main engines began expanding, no longer constrained by atmospheric pressure, resulting in a dramatic litght show in the cockpit. The light flickered and flared sporadically as if a spotlight with a bad connection was sparking on and off. The view was unusual and caught veteran space observers - and some NASA officials - by surprise. But mission control commentator Eileen Hawley said it was all quite normal. "As the crew climbed to orbit, the plume or the cloud that results from the launch, from the engines, begins to move forward and around the orbiter itself, resulting in the kind of flashes of bright light we're seeing in that video," she said. The astronauts signed off for the night shortly before 12:30 a.m. Crew wakeup is scheduled for 8:17 a.m. =================================================================== Shuttle's KU-band antenna fails (10/12/00) 08:30 a.m., 10/12/00, Update: Crew awake; preview of flight day 2 Shuttle Discovery's seven astronauts were awakened at 8:17 a.m. to begin their first full day in space. Three rendezvous rocket firings are planned today to fine tune Discovery's approach to the international space station with docking on tap at 1:43 p.m. Friday. Today's wakeup music was a recording of "Incense and Peppermint" beamed up from mission control. "Discovery, Houston, good morning," astronaut Ellen Ochoa called from the ground. "Welcome to flight day two." "Good morning, Ellen," rookie pilot Pamela Melroy replied. "What a nice way to wake up." Japanese astronaut Koichi Wakata will put the shuttle's 50-foot-long robot arm through its paces starting around 11:17 a.m. this morning to make sure the space crane is healthy and ready for a full slate of space station assembly work. On Saturday, Wakata plans to use the arm to mount the 18,300-pound Z1 truss atop the U.S. Unity module. The $273 million truss houses four stabilizing gyroscopes and will serve as the temporary mounting point for a huge set of solar arrays set for delivery in December. The robot arm also will be used to mount a new $20 million shuttle docking port on Unity's nadir, or Earth-facing, hatch. The port will be used later in the assembly sequence when the U.S. laboratory module Destiny is attached to the port currently used by visiting shuttles. Discovery's four spacewalkers - Leroy Chiao, William McArthur, Jeff Wisoff and Michael Lopez-Alegria - will spend the early afternoon checking out their spacesuits to make sure they are ready for use in four back-to-back spacewalks starting Sunday. The astronauts also will check out the health of their emergency rescue jetpacks, designd to help an astronaut fly back to the shuttle should he or she ever become untethered during a spacewalk. The nitrogen gas jetpacks attach to the base of a spacewalker's backpack. Later today, a Canadian-built computerized television system called the Orbiter Space Vision System, used to precisely position components with the robot arm, will be powered up and tested. At 5:47 p.m., Wakata will participate in a Japanese public affairs event. One hour later, Discovery's docking system attachment ring will be extended to verify its operation and readiness for the space station linkup Friday. The final major item on the agenda today is check out of the crew's laser rangefinders and other gear that will provide critical distance and relative velocity information during the final phase of docking. The astronauts are scheduled to go to bed around 10:17 p.m. 12:20 p.m., 10/12/00, Update: Engineers troubleshoot shuttle TV antennna problem Editor's Note... The following story was written for Spaceflight Now and is reposted here by permission. The shuttle Discovery closed in on the international space station today for a docking Friday amid troubleshooting to fix a potentially serious problem with the shuttle's main television antenna. On a unrelated front, U.S. and Russian flight controllers also are discussing the possibility of changing the timing and location of Friday's space station docking because of expected heavy traffic on Russian communications satellites and ground systems. As a result, Russian flight controllers may elect to send commands to the station during the final rendezvous and docking sequence through an S-band communications system in the station's U.S. Unity module. That likely would change the docking time and location. Regardless of where the linkup occurs, the shuttle's KU-band antenna normally would play a major role. The high-speed antenna system is used to beam data and television back to Earth via NASA's globe-spanning set of communications satellites. The antenna also acts as a radar system during the final phases of rendezvous with the space station. The antenna's forward link, that is, the shuttle-to-Earth link of the communications system, is not working properly and flight engineer William McArthur began troubleshooting procedures just before noon. As one might expect, the first step called for switching the system off and then back on and to re-initialize the system. If the forward link fails to work at all, television from the shuttle would only be possible during infrequent passes over U.S. ground stations. The health of the KU-band rendezvous radar system is not yet known. "The instrumentation and communications officer here in mission control noted it was not working properly when it should have been providing a television downlink," said mission control commentator Kyle Herring. "They were seeing a lot of noise on the signal coming down. "It's yet to be determined whether the impact would be only to the television side of that dish antenna's capability or also the rendezvous radar side of it as well, which is used to assist in the rendezvous with the station. "It is not a formal requirement to have the rendezvous radar capability (to proceed with docking), though it's obviously something that's very useful to the crew on board," Herring said. "There are several different methods for providing rendezvous data to the crew during the final phases of the rendezvous and docking." Discovery currently is scheduled to dock with the space station at 1:43 p.m. Friday as the two spacecraft sail over Ukraine. At contact, the spacecraft will be directly above 48.44 degrees north latitude and 31.37 degrees east longitude. All previous shuttle-station dockings have occurred while the outpost was within range of one or more Russian ground stations to ensure successful realtime commanding. Just before docking, for example, the station's attitude control, or stabilization, system is taken off line to prevent any unexpected motion during the final phase of the shuttle's rendezvous and capture. The system is re-activated after docking is complete. But Russian flight controllers today are assessing whether heavily booked internal communications links can support a docking over a Russian ground station or whether they will have to send their commands through NASA communications links with the U.S. Unity module. If so, the timing and location of the docking likely would change. "The Russians are studying whether they will have the full capability of all of their satellites and ground stations ... for commanding of the station to go into free drift at the time of docking and then back into attitude after hard mate," said NASA spokesman Rob Navias. "Because other Russian customers are using some of their satellite system resources, there is some consideration begin given to altering the docking time." NASA commentator Kyle Herring in mission control said earlier today the Russian flight control team will spend most of the day studying the issue to determine "the appropriate location to rendezvous and dock with the station so the Russian partners can have a good data stream from the Zarya and Zvezda modules." 02:25 p.m., 10/12/00, Update: Shuttle TV antenna appears down for count Troubleshooting to resolve a problem with the shuttle Discovery's KU-band radar and television antenna has not been successful, but NASA managers say the system is not required for Friday's docking with the international space station. "The loss of the TV is going to be an irritant and it's disappointing, because it's fun to watch the TV of these events," said lead flight director Chuck Shaw. "But it is no way an impact to either safety or mission success." But loss of the KU-band radar system, however, will make the final rendezvous sequence a bit more complex for commander Brian Duffy and the loss of television will prevent flight controllers - and the public - from watching the linkup live. Or much of anything else, for that matter. "The troubleshooting continues on the KU-band antenna system," mission control commentator Kyle Herring said shortly after 2 p.m. "At this point, it appears that system is not operational. It's yet to be determined whether that can be recovered. "In the meantime, we will be using still sequential video through the S-band communications, which is basically capturing a snapshot of video every 10 seconds or so, when available, from activities on board the orbiter." The shuttle uses both KU-band and S-band communications links with the ground. The S-band system can route voice and data streams back to mission control through NASA's Tracking and Data Relay System satellites or directly to U.S. ground stations. The high-speed KU-band system uses the same satellites to beam back television and multiple channels of interleaved telemetry. Without the KU-band system, full-motion video can only be transmitted to the ground during infrequent passes over U.S. ground stations. Still images can be downlinked using the S-band system, but only at a rate of one frame every 10 seconds or so. Shaw said live television is not required for safety or mission success and that other sensors - laser range finders and the shuttle's optical star trackers - are available to replace the radar system if necessary during Friday's rendezvous. "I've got to tell you, people want to make it into a big deal," he said. "From an operations impact standpoint, it's not a big deal. I would put it in the irritant category more than an impact category. And that's true." While it might not be formally required, video from the shuttle is certainly a welcome addition to any mission and its loss during Discovery's four-spacewalk flight would mark a major disappointment. On an unrelated front, U.S. and Russian flight controllers have agreed to keep Friday's docking on schedule and not to make any significant changes to the timing or location of the linkup. Expected heavy traffic on internal Russian communications links may prevent controllers in Moscow from sending critical commands to the station through Russian ground stations prior to docking. Instead, they may send the commands through a U.S. communications system to NASA's Unity module for relay to the Russian Zarya and Zvezda modules. Telemetry from the station is expected to be received normally at the Russian ground stations. =================================================================== Discovery docks with international space station (10/13/00) 08:45 a.m., 10/13/00, Update: Shuttle crew sets sights on station docking The Discovery astronauts closed in on the international space station today, working through a complex rendezvous timeline targeted for docking at 1:46 p.m. Perhaps appropriately for a Friday the 13th, the rendezvous will be slightly more complicated than usual because of the failure Thursday of the shuttle's KU-band rendezvous radar system. The astronauts instead will rely on an optical star tracker to update the shuttle's navigation system, along with laser rangefinders. "As you are aware, life on board will be a bit more complicated with th Ku-band system not working," mission controllers wrote in a morning flight plan update. Lead flight director Chuck Shaw described the loss of the rendezvous radar system - and live television from the shuttle - as a "minor irritant." Maybe so. But the loss of realtime TV for the remainder of this dramatic mission is a major disappoinment to just about everyone else. Trailing the station by about nine miles, commander Brian Duffy plans to fire Discovery's maneuvering jets at 10:09 a.m. to begin the final phase of the rendezvous. The shuttle should pass 600 feet directly below the station around 11:39 a.m. It then will loop up directly in front of the outpost 15 minutes later and continue on to a point 250 feet above it at 12:04 p.m. The station will be vertically oriented with the U.S. Unity module facing Discovery and deep space, the Russian Zvezda command module closest to Earth and the Zarya propulsion module sandwiched in between. Today's docking will be timed to take place over the Ukraine as the two spacecraft move into contact with a Russian ground station. As a result, Duffy will hold Discovery at a distance of 170 feet directly above the station until 1:14 p.m. when the approach will resume. He will stop the approach again at a distance of 30 feet for about five minutes before beginning the final push to docking at 1:40 p.m. Here's today's docking timeline (in Eastern time and mission elapsed time): MET TIME.......DD...HH...MM...EVENT 10:09 AM...01...14...52...Terminal initiation rocket firing 10:22 AM...01...15...05...Station maneuvers to star tracker attitude 10:37 AM...01...15...20...Orbital sunset 10:59 AM...01...15...42...Station maneuvers to docking attitude 11:11 AM...01...15...54...Orbital sunrise 11:14 AM...01...15...57...Station in docking attitude 11:23 AM...01...16...06...MC4 rendezvous burn 11:29 AM...01...16...12...Range: 1500 feet 11:34 AM...01...16...17...Range: 1000 feet 11:35 AM...01...16...18...Range: 800 feet 11:39 AM...01...16...22...Range: 600 feet directly below station 11:43 AM...01...16...26...Range: 500 feet 11:54 AM...01...16...37...Range: 350-400 feet in front of station 12:04 PM...01...16...47...Range: 250 feet above station 12:09 PM...01...16...52...Sunset 12:10 PM...01...16...53...Range: 170 feet 12:16 PM...01...16...59...Start stationkeeping at 170 feet 12:17 PM...01...17...00...Russian ground station contact 12:28 PM...01...17...11...Russian ground station loss of contact 12:43 PM...01...17...26...Orbital sunrise 01:09 PM...01...17...52...Latest time to be in docking configuration 01:12 PM...01...17...55...Orbital noon 01:14 PM...01...17...57...End stationkeeping at 170 feet 01:30 PM...01...18...13...Shuttle in contact with NASA comsat 01:35 PM...01...18...18...Start stationkeeping at 30 feet 01:40 PM...01...18...23...End stationkeeping; push to dock 01:41 PM...01...18...24...Orbital sunset 01:42 PM...01...18...25...ISS in range of Russian ground stations 01:44 PM...01...18...27...Docking window opens 01:44 PM...01...18...27...Range: 10 feet 01:46 PM...01...18...29...Space station Docking 01:55 PM...01...18...38...Docking window closes 01:58 PM...01...18...41...Russian ground station loss of contact 02:16 PM...01...18...59...Orbital sunrise "We're going to come in from underneath, actually from behind and then up from underneath," Duffy said in a NASA interview. "And we're going to get to between 600 and 500 feet from the space station and then we're going to just fly around in front of it ... and get above it. "And then we're going to come down from above and we're going to dock from above it as we come down," he said. "Now some of the factors that make it a challenge are we want to maintain the proper range and range rate, because timing is very important. "The reason the timing's important is because we want to be docking with the station while we're over a Russian ground site. So, we have a limited window that we want to be docking within. Staying on the profile and being in the right place at the right time with everything ready to go will be, you know, a bit of a challenge." 10:15 a.m., 10/13/00, Update: Shuttle crew begins terminal rendezvous sequence Commander Brian Duffy fired the shuttle Discovery's maneuvering jets at 10:09 a.m. to begin the final phase of the crew's rendezvous with the international space station. Docking is expected around 1:46 p.m. (see the next entry for details). The failure of the shuttle's KU-band radar/television antenna means flight controllers - and the public - will be unable to watch the docking live. However, Discovery will pass over U.S. ground stations three times later this afternoon and evening, providing three opportunities for the crew to downlink videotape. Those TV downlink windows will open at 6:05 p.m., 7:42 p.m. and 9:11 p.m. Here is the revised television timeline (revision F): ORB..EVENT..................................DD/HH:MM...EDT........GMT FRIDAY, OCTOBER 13 23...CREW WAKEUP(begins FD 3)...............01/10:00...05:17 AM...09:17 24...RENDEZVOUS OPERATIONS BEGIN............01/12:00...07:17 AM...11:17 29.*.DISCOVERY/ISS DOCKING..................01/18:28...01:45 PM...17:45 30...MISSION STATUS BRIEFING..........JSC...01/20:13...03:30 PM...19:30 30.*.PMA-2 INGRESS..........................01/20:30...03:47 PM...19:47 31.*.UNITY INGRESS/EQUIPMENT SETUP..........01/21:30...04:47 PM...20:47 31.*.RMS POWERUP............................01/21:45...05:02 PM...21:02 31.*.RMS PAYLOAD BAY SURVEY.................01/22:00...05:17 PM...21:17 32.*.S-BAND TV DOWNLINK OPPORTUNITY..MILA...01/22:48...06:05 PM...22:05 33.*.S-BAND TV DOWNLINK OPPORTUNITY..MILA...01/00:25...07:42 PM...23:42 32...FLIGHT DAY HIGHLIGHTS (FD 3).....JSC...02/00:43...08:00 PM...00:00 33.*.S-BAND TV DOWNLINK OPPORTUNITY..DFRC...01/01:54...09:11 PM...01:11 33.*.CREW REPORT/HIGHLIGHTS REEL......JSC...02/02:43...10:00 PM...02:00 34...CREW SLEEP BEGINS......................02/03:00...10:17 PM...02:17 10:45 a.m., 10/13/00, Update: Russian TV of docking expected; NASA nixes Zvezda entry While the shuttle's KU-band television antenna is on the blink, eliminating normal live television of today's space station docking, the Russians plan to provide live views of the shuttle as it approaches from a camera mounted on the station.