STS-109 MISSION ARCHIVE Updated: 03/11/02 Hubble Space Telescope Servicing Mission 3B 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 -NASA starts new year with demanding Hubble flight (01/03/02) -'Astronomy Now' mission preview (01/04/02) -Launch officially slips to Feb. 28 (01/14/02) -Columbia hauled to launch pad (01/28/02) -Launch preparations update (02/12/02) -CBS News mission preview (02/25/02) -Cold weather threatens launch; George Page dies (02/26/02) -Launch delayed 24 hours by predicted low temps (02/27/02) -Revised TV sked released (02/28/02) -Columbia blasts off; coolant problem assessed (03/01/02) -Columbia cleared for full-duration mission (03/02/02) -Shuttle crew captures Hubble (03/03/02) -First solar array successfully installed (03/04/02) -Second solar array installed (03/05/02) -Astronauts replace power control unit (03/06/02) -New camera installed during fourth spacewalk (03/07/02) -NICMOS cryocooler installed in final spacewalk (03/08/02) -Hubble released from shuttle (03/09/02) -Astronauts take a day off; reflect on Hubble repair (03/10/02) =================================================================== NASA starts new year with demanding Hubble flight (01/03/02) NASA will begin its six-flight 2002 shuttle launch campaign in late February with a demanding mission to upgrade the Hubble Space Telescope. Launch of shuttle Columbia with a crew of seven currently is targeted for 10:22 a.m. Feb. 21. But the flight could slip an addition week to Feb. 28 because of last-minute work to incorporate replacement of a suspect reaction wheel assembly during the second of five back-to-back spacewalks. If launch does, in fact, slip to Feb. 28, launch would be targeted for around 6:53 a.m. The launch window for mission STS-109 is expected to be about 45 minutes long. While that gives the launch team more time to handle last-minute problems than a space station countdown, the final hold at the T-minus nine-minute mark will be similar, lasting 40 minutes. The hold will begin 49 minutes before liftoff. NASA's 108th shuttle mission is the agency's fourth flight dedicated to servicing the venerable Hubble Space Telescope. Five spacewalks are planned by alternating two-man teams to replace the observatory's solar arrays; to replace its aging power control unit; to install a new high-tech camera; and to install an innovative cooling system to revive a now-dormant infrared camera/spectrometer. Replacement of the power control unit, or PCU, is especially challenging because it was not designed to be removed by spacewalking astronauts. The late addition of a replacement reaction wheel assembly also is complicating mission planning. The one-hour 15-minute RWA replacement will be inserted at the end of the second spacewalk. Work to repair a balky access door latch will be deferred, possibly to the fifth spacewalk, time permitting. A sixth spacewalk is possible if the crew runs into major problems accomplishing one of the mission's primary objectives. A detailed flight plan is posted below. But it does not yet include the reaction wheel removal and replacement and flight planners continue to review the spacewalk timelines. An updated flight plan will be posted here as soon as it's available. In the meantime, here are mission highlights at a glance (in EST and mission elapsed time): DATE/TIME..DD...HH...MM...EVENT 02/21/02 01:02 AM..................External tank fueling begins 06:37 AM..................Crew heads for launch pad 07:02 AM..................Astronauts strap in 09:12 AM..................Start T-minus 20-minute hold 09:22 AM..................Resume countdown 09:33 AM..................Start T-minus nine-minute hold 10:13 AM..................Resume countdown 10:22 AM...00...00...00...STS-109 launch 02/23/02 08:57 AM...01...22...35...HST grapple and berthing 10:12 AM...01...23...50...HST switched to external power 01:07 PM...02...02...45...HST solar array retraction 02/24/02 05:27 AM...02...19...05...Spacewalk 1 begins: Grunsfeld and Linnehan ..........................replace the -V2 solar array 11:52 AM...03...01...30...Airlock repressurization 02/25/02 05:27 AM...03...19...05...Spacewalk 2 begins: Newman and Massimino ..........................replace +V2 solar array; RWA replacement; ..........................PCU replacement preparations 11:52 AM...04...01...30...Airlock repressurization 02/26/02 05:27 AM...04...19...05...Spacewalk 3 begins: Grunsfeld and Linnehan ..........................replace the power control unit 12:22 PM...05...02...00...Airlock repressurization 02/27/02 05:27 AM...05...19...05...Spacewalk 4 begins: Newman and Massimino ..........................install the Advanced Camera for Surveys 11:52 AM...06...01...30...Airlock repressurization 02/28/02 05:27 AM...06...19...05...Spacewalk 5 begins: Grunsfeld and Linnehan ..........................upgrade the NICMOS cooling system 01:57 AM...07...01...35...Airlock repressurization 03/01/02 08:07 AM...07...21...45...HST is released from the shuttle 03/04/02 07:08 AM...10...20...46...Deorbit burn (orbit 164) 08:19 AM...10...21...57...Landing (orbit 165) A detailed mission preview will be posted here in the next few weeks. NASA plans six shuttle missions in 2002 and four or possibly five flights in 2003. Here's the latest launch schedule (some of the following dates are "no-earlier-than" targets; all are subject to change): LAUNCH.....SHUTTLE....MISSION........OBJECTIVE 2002 02/21/02...Columbia...STS-109/HST....Hubble Space Telescope servicing 04/04/02...Atlantis...STS-110/8A.....ISS center (S0) solar array truss 05/02/02...Endeavour..STS-111/UF2....ISS crew rotation 06/27/02...Columbia...STS-107........Research mission; Israeli astronaut 08/01/02...Atlantis...STS-112/9A.....ISS starboard (S1) solar array truss 09/06/02...Endeavour..STS-113/11A....ISS port (P1) solar array truss; crew rotation 2003 01/16/03...Atlantis...STS-114/ULF-1..Crew rotation 04/10/03...Endeavour..STS-115/12A....Solar arrays; port truss (P3/P4) 05/30/03...Atlantis...STS-116/12A.1..Crew rotation; port truss segment (P5) 08/21/03...Endeavour..STS-117/13A....Solar arrays; starboard truss segments (S3/S4) 09/25/03...Columbia...STS-118/13A.1..Crew rotation* *Under review In the near term, the space station astronauts - Expedition 4 commander Yury Onufrienko, Daniel Bursch and Carl Walz - face a busy month with two spacewalks on tap. On Jan. 14, Onujfrienko and Walz will venture outside the station around 3:50 p.m. for a six-hour spacewalk to re-locate a Russian cargo crane. Then, on Jan. 25 (exact time TBD), Onufrienko and Walz will carry out a spacewalk to install ham radio and Russian TV antennas on the station's hull; to install thruster deflectors on the Zvezda command module; to attach contamination monitors; and to retrieve space exposure experiments mounted on the station's hull earlier. On Feb. 27, the station's Progress-6 supply ship will undock from the Zvezda module's aft port. The next day, the Progress-7 craft is scheduled for launch from the Baikonur Cosmodrome for a docking on March 2. A fresh Soyuz re-entry craft will be ferried to the station in mid April. Commander Yuri Gidzenko, European Space Agency astronaut Roberto Vittori and Mark Shuttleworth, a South African space tourist, plan to take off from Baikonur on April 17. If all goes well, they will dock with the station April 19 and return to Earth on April 27 aboard the station's current Soyuz. =================================================================== 'Astronomy Now' mission preview (01/04/02) Editor's Note... The following story was written for Astronomy Now magazine. Since this story was written, NASA managers decided to replace a suspect reaction wheel assembly, or RWA, during the second of five planned spacewalks. Hubble Gets a Makeover By WILLIAM HARWOOD Taking a break from space station assembly work, NASA is gearing up for the next Hubble Space Telescope servicing mission, a high-stakes five-spacewalk flight in February to install new solar arrays, a critical power switching unit and a new camera to extend the observatory's scientific reach. Spacewalking astronauts also will attach a high-tech cooling system to the base of the telescope to revive an infrared camera/spectrometer that's been out of action since January 1999 when the nitrogen ice in its original cryogenic cooling system ran out. From an engineering point of view, the new solar arrays - smaller, stiffer and more powerful than the ones they are replacing - and the new electrical power control unit, or PCU, will give Hubble a new lease on life, resolving current shortcomings and restoring the observatory to near-perfect health. But to install the 160-pound power control unit, which regulates and distributes the electricity from the solar arrays to the rest of the observatory, ground controllers will have to completely shut Hubble down for the first time since launch in 1990. Should an emergency develop that might force the shuttle crew to depart before the swap-out is complete, Hubble would not survive. While the odds of that grim scenario are extremely remote, the PCU replacement is "extremely challenging," says lead flight director Bryan Austin. "It was not designed to be taken out," he told Astronomy Now. "It has 36 connectors and several other ground connectors on the bottom. Those connectors are on the left-hand side, they're not staring right at you. For the suited crewman to reach his hand in there, he's pretty much reaching in there blind." While flight controllers expect surprises along the way, they are confident the astronauts will get the job done, giving Hubble an upgraded power system that should keep it operating through 2010, when NASA plans to terminate operations. From a scientific perspective, the new Advanced Camera for Surveys, or ACS, and the revived Near Infrared Camera and Multi-Object Spectrometer - NICMOS - will keep Hubble competitive with larger ground-based observatories for years to come. And then some. "We're going to put on a new camera, the Advanced Camera for Surveys, which has two times the field of view and five times the sensitivity of the current Wide-Field Planetary Camera 2," said David Leckrone, Hubble program scientist. "It will be about 10 times more efficient, which means in a given amount of observing time it'll go fainter by quite a bit and also cover a broader field of view with better resolution. So it's going to be a gang busters camera and it will become the work horse camera, supplanting WFPC." As for restoring NICMOS to good health, "the near infrared capability on Hubble is really fundamental to our mission," Leckrone said. "That extra factor of two in wavelength, between one micron and two microns, really does make a big difference in what people can do." NASA originally intended to launch the third in a series of Hubble servicing missions in June 2000. But by February of 1999, three of the gyroscopes that help lock the telescope on astronomical targets had failed because of subtle age-related breakdowns. The three remaining gyros were the bare minimum necessary for scientific observations. Justifiably worried that one more failure would put Hubble into electronic hibernation, NASA managers decided to break the third Hubble servicing mission into two parts and to launch the first, known as Servicing Mission 3A, in October 1999. As it turned out, work to repair shuttle wiring problems, replace a main engine and repair a crushed hydrogen line pushed Hubble Servicing Mission 3A to mid December. But once in orbit, the astronauts accomplished virtually all of their objectives, installing six new gyroscopes, a new fine guidance sensor, an upgraded flight computer, a new solid-state data recorder, voltage regulators to improve battery performance and a new S-band radio transmitter. If all goes well, Columbia will blast off on Hubble Servicing Mission 3B on 14 February (Editor's note: The current target launch date is Feb. 28). On board will be commander Scott Altman, pilot Duane Carey, robot arm operator Nancy Currie and spacewalkers John Grunsfeld (a veteran of servicing mission 3A), Richard Linnehan, James Newman and Michael Massimino. The shuttle will catch up with the space telescope two days after liftoff. Currie, operating the ship's 50-foot-long robot arm, will then pluck it out of open space and mount it vertically on a lazy Susan-type rotating work bench at the back of Columbia's cargo bay. A motorized shuttle power cable will be plugged in and the telescope's two solar arrays will be commanded to roll up like window shades. The day after that, the spacewalks begin. The astronauts will work in alternating two-man teams, with Grunsfeld and Linnehan carrying out the first, third and fifth spacewalks to install one solar array, the new PCU and the NICMOS coolant system. Newman and Massimino will install the second solar array and the Advanced camera for Surveys on the second and fourth spacewalks. The new solar arrays will generate 5,270 watts of power, 670 watts more than the arrays they are replacing. They weigh more - 640 pounds per wing vs 339 pounds for the old panels - but they are much smaller: 23 feet long compared to 40 feet for the old arrays. The additional power output of the new array will enable four scientific instruments to operate simultaneously for the first time. Once the old arrays are removed, installation of the new panels should be fairly straight forward. The spacewalkers also will install electronic gear that will allow engineers on the ground to control the arrays' electrical output. The relays will be used to "safe" the spacecraft before installation of the PCU on the third spacewalk. The PCU changeout is expected to take at least seven hours, 30 minutes longer than NASA normally plans for spacewalks. But with 36 difficult connectors to unplug and reconnect, Grunsfeld and Linnehan will need all the time they can get. "We're bookkeeping just a couple of minutes for connector mate, connector demate," said Austin. "So multiply that times 36, that's a lot of time. And if you're off by 30 seconds times 36 of those, that's about 15 minutes or so. Things can add up real easily if you start to run into problems." The Advanced Camera for Surveys will be installed in place of the telescope's Faint Object Camera, the last instrument to use the COSTAR suite of corrective mirrors installed in 1993 to correct the telescope's spherical aberration. The ACS and the rest of the observatory's more current instruments have their own corrective mirrors. COSTAR itself will be removed during Servicing Mission 4 in August 2004 and replaced with yet another high-tech instrument. The infrared-sensitive NICMOS was installed in February 1997. But it used up its nitrogen ice coolant faster than expected and was shut down in 1999. The new cooling system uses neon gas, an external radiator and a small, 400,000-rpm turbine to carry heat away from the instrument. The new "cryocooler" will chill the infrared detectors in NICMOS to minus 334 degrees Fahrenheit, slightly higher than it's original operating temperature but cold enough to do valuable science. If all goes well, NICMOS will remain operational for at least five years. =================================================================== Launch officially slips to Feb. 28 (01/14/02) As expected, NASA managers have agreed to delay the shuttle Columbia's launch on a mission to upgrade the Hubble Space Telescope from Feb. 21 to Feb. 28. The decision was made last week but due to an oversight on our part, this page was not updated to reflect the official change. Our apologies! An updated flight plan, targeting launch at 6:53 a.m. on Feb. 28, is posted below. It now reflects plans to replace a reaction wheel assembly during the second spacewalk and to defer repair of an aft shroud latch from EVA-2 to the fifth spacewalk. A quick glance at the flight plan shows the five back-to-back spacewalks needed to upgrade the space telescope will begin around 2 a.m. each day with one starting an hour earlier. Landing is targeted for just after 5 p.m. on March 11. Here's a quick look at mission highlights, assuming a launch on Feb. 28 (in Eastern and mission elapsed time): EST........DD...HH...MM...EVENT 02/28/02 06:53 AM...00...00...00...STS-109 launch 03/01/02 08:58 AM...01...02...05...Media interview opportunity 11:18 PM...01...16...25...Begin rendezvous timeline 03/02/02 04:01 AM...01...21...08...Hubble Space Telescope grapple and berthing 04:28 AM...01...21...35...HST latched to flight support structure 07:58 AM...02...01...05...HST: Solar array retraction 03/03/02 01:58 AM...02...19...05...Spacewalk-1: Airlock egress 03:03 AM...02...20...10...Spacewalk-1: -V2 solar array installation 08:08 AM...03...01...15...Spacewalk-1: Airlock ingress 03/04/02 01:58 AM...03...19...05...Spacewalk-2: Airlock egress 02:38 AM...03...19...45...Spacewalk-2: +V2 solar array installation 06:38 AM...03...23...45...Spacewalk-2: Reaction wheel assembly replacement 08:18 AM...04...01...25...Spacewalk-2: Airlock ingress 03/05/02 12:58 AM...04...18...05...Spacewalk-3: Airlock egress 01:23 AM...04...18...30...Spacewalk-3: Power control unit replacement begins 07:38 AM...05...00...45...Spacewalk-3: Airlock ingress 03/06/02 01:58 AM...05...19...05...Spacewalk-4: Airlock egress 02:23 AM...05...19...30...Spacewalk-4: Advanced Camera for Surveys installation begins 08:08 AM...06...01...15...Spacewalk-4: Airlock ingress 03/07/02 01:58 AM...06...19...05...Spacewalk-5: Airlock egress 02:23 AM...06...19...30...Spacewalk-5: Aft shroud latch repair 02:53 AM...06...20...00...Spacewalk-5: NICMOS cryo cooler system installation 05:08 AM...06...22...15...Spacewalk-5: Cryocooler radiator installation 08:43 AM...07...01...50...Spacewalk-5: Airlock ingress 03/08/02 04:57 AM...07...22...04...HST is released from the shuttle 08:23 AM...08...01...30...Media interview opportunity 03/09/02 08:43 AM...09...01...50...Media interview opportunity 03/10/02 12:53 AM...09...18...00...Crew news conference 03/11/02 03:54 AM...10...21...01...Deorbit burn (rev. 164) 05:04 AM...10...22...11...Landing (rev. 165) =================================================================== Columbia hauled to launch pad (01/28/02) United Space Alliance engineers hauled the shuttle Columbia to pad 39A today for work to ready NASA's oldest orbiter for a five-spacewalk flight next month to upgrade the Hubble Space Telescope. This will be Columbia's first flight since August 1999 when the shuttle returned to Earth after ferrying the Chandra X-ray Observatory into orbit. Since then, Columbia has undergone months of inspections and upgrades in Palmdale, Calif., along with work to fix or replace worn wiring. A short circuit during its last launch left the orbiter one failure away from an engine shutdown. NASA originally planned to move Columbia to the pad for the Hubble mission late last week. But the three-mile-trip was delayed because of a bad bearing in the ship's crawler-transporter. The six-hour move began today - the 16th anniversary of the Challenger disaster - around 6:38 a.m. An updated flight plan has been posted below, along with a countdown chart and an ascent events summary. =================================================================== Launch preparations update (02/12/02) A few minor notes... Overlapping abort regimes: Because Columbia is launching with a an lightweight cargo, the return-to-launch site and abort-to-orbit abort regimes overlap for this mission. As a result, only one trans-Atlantic landing site will be staffed - Ben Guerir in Morocco - and good weather there is not a flight rule requirement. In other words, Columbia can launch without a TAL abort site. Reaction wheel assembly update: The RWA scheduled for installation aboard the Hubble Space Telescope has been declared "no go." A backup RWA is in the process of being tested and qualified at the Goddard Space Flight Center. No impact on the launch date is expected. Pad flow timeline: As of today, there is no contingency time left in the STS-109 flow at pad 39A. =================================================================== CBS News mission preview (02/25/02) The Hubble Space Telescope has cost U.S. taxpayers more than $6 billion in the quarter century since the project was approved. But to astronomers around the world, the 24,000-pound satellite is, quite simply, priceless. Since its famously flawed optical system was repaired by spacewalking astronauts in 1993, the Hubble Space Telescope has become an international icon of science, one of the most productive astronomical observatories ever built and the flagship of NASA's exploration of the universe. The remotely-controlled spacecraft has helped astronomers confirm the existence of black holes, zero in on the true age of the universe and spot the faint glimmer of stars in galaxies born within a billion years or so of the big bang birth of the cosmos. Its spectacular photographs have charted the life cycles of distant suns in glorious detail, providing unmatched views of stellar nurseries and the explosive end results of stellar evolution. It has catalogued myriad infant solar systems in the process of forming planets and provided flyby-class views of the outer planets in Earth's own solar system, routinely capturing phenomena as common as dust storms on Mars to the once-in-a-lifetime crash of a comet into giant Jupiter. While huge ground-based telescopes now rival and in some areas exceed the power of Hubble's relatively modest 94.5-inch primary mirror, the space telescope, operating 350 miles up, high above the turbulence of Earth's atmosphere, remains in a class by itself. "I think everyone would agree the Hubble Space Telescope has been one of this country's most valuable scientific assets for its 12-year operating life," said Phil Engelauf, a shuttle mission manager at the Johnson Space Center in Houston. But Hubble's ability to continue making world-class observations, he said, "is really enabled by our ability to keep the spacecraft healthy and scientifically relevant by updating and servicing that spacecraft on orbit." And so, at 6:48 a.m. Thursday, NASA plans to launch the shuttle Columbia on the fourth of five planned Hubble servicing missions, the most technically challenging - and risky - overhaul and upgrade the space agency has ever attempted. During five back-to-back spacewalks, four astronauts working in two-man teams plan to install a set of smaller-but-more-powerful solar arrays, a power control unit to more efficiently route that power to Hubble's subsystems and a new gyroscopic reaction wheel assembly to help the telescope move, or slew, from one target to another. While installation of the new solar arrays and the reaction wheel assembly are relatively straight forward, the power control unit, or PCU, was not designed to be serviced in orbit and its replacement marks the riskiest part of Columbia's mission. Not only is the replacement physically difficult, ground controllers will have to completely shut Hubble down for the first time since launch in 1990 before the astronauts can begin the critical transplant. "That scares me a lot, it kind of violates a long-standing policy in the space business that if something's working well you turn it off and just hope it comes back on," said Edward Weiler, NASA's associate administrator for space science. "We're not doing that cavalierly, we fully anticipate that everything will work just fine," he said. "But it is a risk that we've never faced before. So this mission is no cakewalk." On the scientific front, the astronauts will install a $75 million 870-pound digital camera called the Advanced Camera for Surveys, or ACS, with twice the resolution and five times the sensitivity of the upgraded Wide Field-Planetary Camera - WFPC-2 - that currently is in place. "With ACS, Hubble will detect more faint stars and galaxies during its first 18 months than have been detected with all of the previous Hubble instruments," said principal investigator Holland Ford of Johns Hopkins University. "For astronomers, those stars and galaxies in the data archive are money in the bank." The Columbia astronauts also will attempt to revive Hubble's Near Infrared Camera and Multi-Object Spectrometer, or NICMOS, an instrument designed to operate at near absolute zero to detect the faint heat of stars and galaxies in the remotest depths of space and time. Installed during the second Hubble servicing mission in 1997, NICMOS was victim of an internal "thermal short" that caused its nitrogen ice dewar to come in contact with surrounding structure. As a result, the instrument's nitrogen ice coolant sublimated away faster than expected, leaving NICMOS dormant after just two-and-a-half years. To repair the instrument, the Columbia astronauts will install an experimental "cryocooler" that uses neon gas and three tiny turbines spinning at an astonishing 400,000 rpm to chill NICMOS to about 75 degrees above absolute zero. But it will not be easy. The astronauts will have to work deep inside the telescope's lower instrument bay to connect the cryocooler to NICMOS and attach a 13-foot-long radiator to the side of the telescope to dissipate the unwanted heat. Cables and coolant lines from the radiator to the cryocooler will be snaked through a small vent opening in the telescope's aft bulkhead. "We believe we now have in hand a new technology developed jointly by NASA and the Air Force, which gives us the first really good shot at a reliable, mechanical cooler in space on an infrared instrument," said David Leckrone, Hubble project scientist at the Goddard Space Flight Center. "So a very important objective of Servicing Mission 3B is, as an experiment, to try this new technology and see if we can bring the NICMOS instrument back from the dead." But because of the experimental nature of the cryocooler, the NICMOS repair falls to the bottom of NASA's list of priorities for Hubble Servicing Mission 3B and as such, it will not be attempted until the fifth and final spacewalk. The top scientific priority, as one might expect, is installation of the Advanced Camera for Surveys. The ACS, about the size of a phone booth, will be installed in place of a no-longer-used instrument called the Faint Object Camera. The ACS actually includes three cameras sensitive to a broad range of wavelengths, from the ultraviolet to the far infrared. To visualize the power of the ACS, it helps to recall one of the telescope's most famous photographs, the so-called "Hubble Deep Field," one of the most remarkable images ever produced by the space telescope. In December 1995, Hubble was aimed at a presumably empty patch of sky near the Big Dipper about the size of a rice grain held at arm's length. The spot was chosen specifically because it appeared, for all practical purposes, to be devoid of stars and galaxies. Over the next 10 days, WFPC-2 took 342 images that later were digitally combined. In the resulting Hubble Deep Field image, amazed astronomers counted some 1,500 discernible galaxies, or fragments of galaxies, dating back to a billion years or so of the big bang. "The Hubble Deep Field, one of humanity's and Hubble's singular achievements, can be done in two days instead of 10 days," said Ford. "A ten-fold increase is especially important for finding rare objects such as the first galaxies and distant supernovae." Working in tandem with a revived NICMOS, the Advanced Camera for Surveys also will play a major role in one of the hottest fields in modern astronomy, the ongoing search for exploding stars called type 1A supernovae. Consider a binary star system that includes a compact white dwarf. The smaller white dwarf's gravity may pull in gas and dust from the companion star. If the white dwarf's mass builds up to about 1.4 times that of the sun, catastrophic fusion reactions begin and the star explodes in a type 1A supernova. By definition, all type 1A supernovae involve stars of roughly the same mass and the intensity of the emitted light follows a well-defined "light curve," brightening and then fading away. The intensity of the light can be used to infer the supernova's distance from Earth and spectroscopic analysis can provide a measure of its recession velocity. Astronomers have long assumed the expansion of the universe is slowing down. And based on the presumed rate of that deceleration, one would expect to find certain brightness levels for type 1A supernovae at various points in time and space after the big bang. But to the surprise of everyone in the astronomical community, researchers in the late 1990s discovered type 1A supernovae at extreme distances appeared dimmer than one would expect based on their observed recession velocities. As it turned out, the only reasonable - though counterintuitive - explanation was to assume the expansion of the universe is actually accelerating. The nature of the "dark energy" powering that acceleration is a complete unknown and determining its nature is a top astronomical priority. "This is an amazing time for both physics and astronomy," said David Leckrone, Hubble project scientist at the Goddard Space Flight Center. "We've come to start to realize over the past few years that we do not understand 95 percent of the content of the universe in which we live. "Between dark matter and dark energy, those two things together constitute approximately 95 percent of the total energy and mass balance, or budget, of the universe," he said. "These are very challenging physical problems. "What is the nature of dark energy, that may well be the most important question in the physical sciences today. The beauty of (ACS and NICMOS) is they give us very powerful tools for beginning to address these very fundamental and revolutionary new issues in physics." UPGRADED COLUMBIA SET FOR MORNING BLASTOFF Columbia, NASA's oldest space shuttle, returns to service after two years of structural inspections, upgrades and wiring repairs. During its most recent launch in July 1999, a short circuit seconds after liftoff left the orbiter one failure away from premature engine shut down. Now equipped with modern flat-panel cockpit displays and other improvements, Columbia is scheduled to rocket away from pad 39A at 6:48:14 a.m. on Feb. 28 to kick off its 27th mission in 21 years of service. "This has been an extensive down period for Columbia, probably the most extensive that we've done," said NASA test director Steve Altemus. "This orbiter went through the most extensive wiring inspection and modifications of any of the orbiters, so that gives us high confidence we've got the vehicle working properly with respect to wiring. "We've got some upgrades that are going to improve safety and reliability and performance. This orbiter was taken apart and put back together in such a manner that we have nothing but the highest confidence it's going to perform like it always does on orbit, which is essentially flawless." At the controls for launch will be commander Scott Altman, pilot Duane Carey and flight engineer Nancy Currie. Their crewmates are spacewalkers John Grunsfeld, veteran of the most recent Hubble servicing mission, Richard Linnehan, James Newman and Michael Massimino. Grunsfeld and Linnehan are responsible for the first, third and fifth spacewalks, during which they plan to install one of the new solar arrays, the power control unit and the NICMOS cryocooler. Newman and Massimino plan to install the second solar array and the reaction wheel assembly during the second EVA and the Advanced Camera for Surveys during the fourth. If all goes well, Altman will guide Columbia to a rendezvous with Hubble two days after launch, approaching the telescope from directly below. By that point, the telescope's two KU-band antennas will have been folded up against the body of the spacecraft and its two solar arrays will be oriented parallel to the long axis of the observatory. Assuming an on-time liftoff, Currie, operating the shuttle's 50-foot-long robot arm, will snare the spacecraft around 4 a.m. on March 2. She then will lower Hubble's base onto a lazy Susan-type rotating service platform at the rear of Columbia's cargo bay. Three latches will engage to lock the telescope down and an umbilical will be extended to provide power from the shuttle's fuel cells. As viewed from Columbia's aft flight deck, Hubble's two solar arrays will appear face on to the left and right of the telescope's tube, which will extend straight out of the cargo bay. By convention, the left-side array is on the telescope's minus V2 axis while the right-side array is on the plus V2 axis. The arrays were installed during the first Hubble servicing mission in 1993. They weigh 339 pounds each and measure 40 feet long by 10.8 feet wide, delivering about 4,600 watts of power from silicon solar cells. Because of the wear and tear of temperature extremes and normal space radiation, the flexible panels now provide just 63 percent of their original power. In addition, they suffer from structural problems and some shorted circuitry in the wiring connecting all the solar cells. Designed for Iridium communications satellites, Hubble's new arrays are heavier - 640 pounds per wing - and more powerful, generating some 5,270 watts. But they are smaller than Hubble's flexible panels, measuring just 23 feet long and 8.5 feet wide. The additional power generated by the new gallium arsenide solar cells will enable astronomers for the first time to operate all of Hubble's instruments at the same time for simultaneous multi-disciplinary observations. In addition, their smaller size will reduce the atmospheric drag that constantly acts to reduce Hubble's altitude. Before the new arrays can be attached, however, the old wings must be rolled up, a task that will be carried out about four hours after the telescope is captured. First, the astronauts, operating the servicing platform by remote control, will tilt Hubble forward and rotate it counter clockwise so the -V2 array is facing the crew cabin. Once that array has rolled up - the process is expected to take about eight minutes per wing - the telescope will be rotated 180 degrees clockwise to bring the +V2 array forward. There is a bit of uncertainty about whether the arrays will, in fact, smoothly roll back up. During the first servicing mission in 1993, a similar array jammed and failed to retract, forcing the astronauts to dump it overboard. Should Columbia's crew run into similar problems, Grunsfeld and Linnehan will simply jettison one or both arrays as required at the start of their first spacewalk. In addition, there's a slight chance brittle insulation surrounding he external framework of the arrays could flake off during the retraction procedure, creating a small cloud of dusty debris. But mission managers are optimistic the arrays will roll up as planned and even if a small amount of insulation does, in fact, flake off, Altman could simply move the shuttle away slightly, eliminating any chance of contamination. In any case, once Hubble is on orbiter power and the arrays are rolled up, the stage will be set for the most grueling set of spacewalks yet attempted by NASA. MISSION PRIORITIES: A PUZZLE WITH JUST ONE SOLUTION With five spacewalks, one might think the objectives of each excursion would match up with the mission priorities, with the highest priority item installed during the first spacewalk and so on down the line. In reality, the puzzle only fits together one way. And contrary to what one might assume, installation of the ACS and the NICMOS cryocooler are not the top priorities. "Establishing the priorities on a Hubble mission is a challenging job in and of itself," said Engelauf, the HST SM-3B mission manager. "You can ask 15 different people and get different perspectives on what's the most important thing to do. "The unique aspect of the Hubble is that it is a long-term program and an on-going vehicle and as such, you have to protect the health of the facility in order to assure the continued return of the science. "As the priorities ultimately came out, protecting the health of the facility is the highest priority because you can't get science unless the facility is healthy," Engelauf said. "And then upgrading or advancing its capability to do new and more relevant science is behind that." The highest priority item on NASA list is the reaction wheel assembly, one of four gyroscopes that ground controllers speed up or slow down to move the telescope from one target to another. Last November, gyro speed telemetry from RWA-1 briefly dropped out, the result of an internal electrical problem. While Hubble can operate with just three RWAs, another problem would leave the telescope unable to slew and thus, unable to accomplish any scientific observations. Playing it safe, mission managers added the RWA swap-out to Columbia's mission at the last minute. And given its critical nature, the RWA is the highest priority of the mission. The next highest priority is replacement of Hubble's central power control unit, followed by installation of the ACS and the NICMOS cryocooler in that order. Priorities aside, the most technically complex task is installation of the power control unit followed by the NICMOS cryocooler and the solar arrays. The most straight-forward tasks are installation of the ACS and the reaction wheel assembly. But the order of the spacewalks was not dictated by either mission priority or technical complexity. Because of the inter-related nature of the upgrades, mission managers were faced with a single "best fit" option. "It's like a puzzle," said lead flight director Bryan Austin. "In putting the puzzle together, the board is only so big, it fits five EVAs, and the puzzle pieces unfortunately are big and they only fit really in one way. And so that's how the mission has laid out." The new solar arrays are being installed first, during the first two spacewalks, because associated diode controller boxes will allow ground controllers to better manage the electrical system when Hubble is shut down for the power control unit replacement. RWA-1 will be installed near the end of the second spacewalk, after the +V2 array is installed. "We need to do the solar arrays first, before we do the PCU, because there are some capabilities we're adding on the new solar arrays - diode boxes, relay controls - that allow the ground to control some relays and safing of the power systems to do the PCU," Austin said. The PCU installation, certainly the riskiest procedure that will be attempted, is scheduled for the third spacewalk. Only then, with Hubble's most critical systems healthy, will the astronauts proceed to installation of the Advanced Camera for Surveys and the NICMOS cryocooler. "We have five EVAs, they are very full EVAs, the tasks are long," Austin said. "In a sense, that complexity has made this mission a little more straight forward in how we planned out these five EVAs. They really only fit in one logical order." Hubble program manager Preston Burch described the overhaul as "an enormous job." "Two of the five items that they'll be installing, namely the power control unit and the NICMOS cooling system, are outside of the previous Hubble servicing experience base," he said. "Every minute of EVA time throughout the five EVA days will be precious. To maximize the probability of success, the astronauts on this mission have trained harder than on any previous Hubble servicing mission." HUBBLE'S POWER SYSTEM GETS MAJOR UPGRADE Installation of the new arrays should be relatively straight forward. Grunsfeld and Linnehan will install the -V2 array early Sunday, with Linnehan initially riding Columbia's robot arm and Grunsfeld the designated "free floater." Grunsfeld will disconnect the old array and Linnehan will temporarily mount it on a cargo carrier in the payload bay. Grunsfeld then will install a diode box needed to ensure power from the arrays flows to Hubble's batteries and not vice versa while Linnehan pulls the new array, folded in half, from its carrier. Grunsfeld will attach the new solar wing, crank it open and wire it to the diode box. Another cable, known as P601, will be connected to route power to a diode box controller. The spacewalkers also will do a bit of preparatory work needed before Hubble can be powered down for replacement of the power control unit during the third spacewalk. They will install a light shield over Hubble's star trackers and thermal covers over the Wide Field-Planetary Camera-2 and equipment bays five and 10. The second solar wing will be installed the next day by Newman and Massimino, who will ride Columbia's robot arm throughout the excursion. Once the +V2 array is in place, the spacewalkers will replace reaction wheel assembly No. 1, engaging three latches and hooking up four cable connectors. The task is expected to take about an hour. Newman and Massimino also will remove bolts from equipment bays two and four, which will be opened for the PCU swap-out during the third spacewalk. "The PCU is quite a unique task in that to do everything that's needed to be done, to prepare the vehicle to be powered down with some of the thermal covers we're putting on, to do the PCU changeout and then to take off those thermal covers so the vehicle can do science again, that whole long task is about eight hours of EVA time," Austin said. "And we can't do that all in one EVA. So what we've done is we've found an optimized time on the first two EVAs to go do some of this prepartory work done." Once Hubble is shut down for the PCU change out, an imaginary "thermal clock" will start ticking. The astronauts must complete the PCU replacement and restore power by the end of the day, or Hubble's critical systems could be damaged by the effects of the normal temperature extremes of space. While NASA managers typically downplay the drama associated with key events like this one, Anne Kinney, director of astronomy and physics at NASA headquarters, said she was "nervous as hell" about the PCU swap out. "It's extremely challenging, it was not designed to be taken out," Austin said of the 160-pound black box. "The original one has 36 connectors and several other ground connectors on the bottom." The PCU measures one foot by two feet by four feet long. "What makes it difficult is, as you're facing the PCU, those connectors are on the left-hand side, they're not staring right at you, they're on the left face," he said. "And that's on the side that that bay door is hinged. For the suited crewman to reach his hand in there, he's pretty much reaching in there blind. "I kind of equate it to changing out spark plugs on your car. There's always those spark plugs down there where you sort of can't see real well, you've just got to go down and feel and make sure you're oriented such that you're unscrewing it without a lot of offset force." Grunsfeld and Linnehan will start EVA-3 an hour earlier than usual because the job is expected to take at least seven-and-a-half hours. While a half hour of contingency time is built into that schedule, the spacewalk could run even longer. But nine hours is the limit on NASA's current spacesuits. Grunsfeld will begin the spacewalk as the free floater, installing thermal covers on the new solar array diode boxes and deploying thermal shields over equipment bays five and 10 that were put in place by Newman and Massimino. At the same time, Linnehan, riding the robot arm, will disconnect Hubble's six batteries. Three batteries are located in equipment bay two and the other three are in bay three. Grunsfeld then will deploy the light shields put in place over the telescope's star trackers during the first spacewalk. The astronauts then will open bay four and begin the tedious job of disconnecting and removing the PCU. After latching the door open and installing a plastic cable holder to keep the connectors in order after they are removed, Linnehan will begin disconnecting the PCU, starting at the top and working down the double rows of cables. With six cables to go, Grunsfeld will take Linnehan's place on the arm, complete the PCU's electrical disconnection and remove it. He then will install the new PCU and make all 36 electrical connections. "These are not our typical fully EVA- friendly connectors with the big wing tabs on them that make it convenient for an EVA-suited crewman to manipulate," Austin said. "We've worked really hard to have a special tool that we're going to use to get a good grip on these and get through this." In addition, the left side of the new PCU is canted slightly, giving Grunsfeld slightly better access for re-attaching the electrical cables. Assuming all goes well, the astronauts will reconnect Hubble's six batteries and retract the thermal covers, clearing the way for anxious ground controllers to re-power the observatory. Austin said mission planners designed all five spacewalks with various "breakout" points to ensure the telescope can be left in a safe configuration overnight in case any given task cannot be completed during a single EVA. "There is a period of time, though, on EVA-3, the PCU, where it's kind of like open heart surgery except we don't have it on a heart-lung machine, we've just taken the heart out and we've got that period of time before the telescope is even awake again, before it's even viable to be powered through the orbiter," he said. "So we've got a minimum amount of work we have to do that day once we take the PCU out, get it back in and get some minimum amount of connectors hooked back up so at least we can apply power from the orbiter back through the telescope to revitalize it. So that day will be extensive." Various contingency plans have been developed to provide enough power to Hubble to keep the observatory alive overnight in case of problems completing the PCU installation. Eleven of the 36 connectors are needed to keep Hubble safe overnight with its batteries still disconnected. At least 23 of the connectors must be hooked up before Hubble can be released from the shuttle. EXTENDING HUBBLE'S SCIENTIFIC REACH After the drama of the powerdown, PCU installation and, presumably, Hubble's safe power up, the astronauts will turn their attention to increasing the telescope's scientific horsepower by installing the Advanced Camera for Surveys. Unlike the PCU, the advanced camera was designed to be user friendly and installation should be relatively straight forward. Newman, riding the robot arm, first will remove Hubble's no-longer-used Faint Object Camera, which will be temporarily mounted on the side of the shuttle's cargo bay. The Faint Object Camera was the last of Hubble's instruments to use COSTAR, the set of corrective optics installed in 1993 that counteracted the spherical aberration of the telescope's primary mirror. COSTAR's optical bench already has been stowed and it will be replaced by another science instrument during the next Hubble servicing mission. While Newman is moving the FOC to its temporary payload bay mounting point, leaving that portion of Hubble's instrument bay empty, Massimino will partially enter the telescope and install a cooling system cable harness that later will be hooked up to the NICMOS cryocooler system. Newman then will pull the ACS from its cargo carrier and, with guidance cues from Massimino, slide it into place inside the observatory. After stowing the FOC in the ACS cargo carrier, Newman and Massimino will trade places on the robot arm and install a NICMOS cryocooler electronics module on the floor of the aft bay just in front of the Advanced Camera for Surveys. After closing the aft shroud doors, the spacewalkers will remove the thermal and light shields installed earlier for the PCU replacement and tighten up the covers over equipment bays two and four. And that will set the stage for the fifth and final spacewalk of Servicing Mission 3B, installation of the NICMOS cryocooler. While it is the lowest priority task of all five spacewalks, it is one of the most technically challenging. First, Linnehan, riding the robot arm, will remove the 300-pound cryocooler from its cargo carrier and latch it to the bulkhead floor of Hubble's aft instrument bay directly in front of the NICMOS instrument. The astronauts will trade places and Currie will guide Grunsfeld down into the cargo bay to retrieve the cryocooler radiator. Linnehan, meanwhile, will float into the telescope to hook up various electrical and cooling lines between NICMOS and the cryocooler. "We're going to put Rick in the telescope with one of the doors closed," Grunsfeld said. "He'll be in basically all the way up to his ankles, replumbing the inside of the telescope to the NICMOS instrument from the cryocooler. That's a point where's he's really all alone by himself inside the telescope." The astronauts then will mount the 13-foot-long radiator to Hubble's exterior. Linnehan, anchored in a foot restraint, will feed ammonia coolant lines and electrical connectors from the radiator through a vent opening in the telescope's aft bulkhead. Grunsfeld, now working inside the aft instrument bay, will pull the lines through and make final connections. "Snaking the various coolant lines and electrical connectors through the bottom of the telescope is a task we have no real data on, it's the kind of thing we've never done on Hubble, it was never anticipated when Hubble was designed that we'd be hanging radiators on the outside and plumbing them through the bottom," Grunsfeld said. "So that's a task we're going to find out how hard it is in real time." Engineers say it will take about a week for NICMOS to fully cool down once the cryocooler is activated. If all goes well, the first test images should be snapped about a month later. "The NICMOS cooling system works like the refrigerator in your kitchen," said Burch. "It's a closed loop system, it's a mechanical device, it's basically a heat pump. It uses neon gas, it compresses it and then allows it to expand and gets a cooling effect. Then the heat is dumped overboard through the radiator. "In theory, the NICMOS cooling system, operating in the weightless environment, the life of the NICMOS cooling system could be indefinite." If it works. Leckrone said "if we don't get it done, we'll be disappointed; I don't want to say we'll be surprised." But NICMOS is crucial to the search for type 1A supernovae and other planned studies of the early universe. About 20 percent of Hubble's post-3B observation time has been booked by NICMOS researchers. NASA managers are protecting an option for staging a sixth spacewalk if problems are encountered in the first five that prevent the astronaut from completing a critical task. While the additional EVA would be used to complete a task, it would not be used to begin one. If the NICMOS cryocooler installation has not been started by the end of the fifth spacewalk, it will not be attempted at all. "I'm a professional astrophysicist by training and so for this mission, it's a combination of holy grail and pilgrimage to be able to go up to the Hubble Space Telescope," Grunsfeld said. "Hubble is really our window to the whole universe. We're going up to not only make some improvements to Hubble, but really to make it much better than new, make it much better than it was when it was launched in 1990 as far as spacecraft capability. "That being said, when we went to the moon the inspirational words were, 'we choose to do these things not because they're easy, but because they're hard.' And this mission is going to be a hard one." =================================================================== 10:45 a.m., 02/25/02, Update: Shuttle countdown begins The shuttle Columbia's countdown to blastoff Thursday on a critical mission to upgrade the Hubble Space Telescope began at 10 a.m. today, setting the stage for a five-spacewalk flight that marks one of the most complex orbital overhauls ever attempted. Launch of the 108th shuttle mission is targeted for 6:48:14 a.m. Thursday at the opening of a 66-minute launch window. There are no technical problems of any significance at pad 39A and the forecast calls for a 70 percent chance of good weather. Columbia's seven-member crew - commander Scott Altman, pilot Duane Carey, flight engineer Nancy Currie and spacewalkers John Grunsfeld, Richard Linnehan, James Newman and Michael Massimino - arrived at the Kennedy Space Center around 1 a.m. this morning. "To fly down was really a treat tonight, to fly over the orbiter and take a look at it sitting there on the pad, it looks ready to go," Altman said at the shuttle runway. "This crew is ready to go. Everybody has worked really hard to get us ready, to get the vehicle ready and we're really looking forward to it." Earlier Sunday, the four surviving Mercury astronauts participated in a celebration at the nearby visitor's center marking the 40th anniversary of John Glenn's historic flight to become the first American in orbit. "The timing is really great, as we're looking back on 40 years of Americans orbiting the Earth and just doing tremendous things in space," Altman said. "Hubble's been a big part of that for over the last 10 years and we're looking forward to making it better, to extend its reach even farther, deeper into the universe. I think it's going to be just a tremendous mission and we're all incredibly thrilled to be a part of it." As usual, the weather could be a factor for Thursday's launch. Forecasters are predicting a temperature of 40 degrees at the opening of the launch period, just a few degrees above NASA's post-Challenger safety limit. The forecast for a Friday launching improves slightly, but conditions are expected to be 70 percent "no go" should launch slip to Saturday for some reason. Assuming an on-time liftoff, Columbia will rendezvous with the Hubble Space Telescope Saturday and the first of five back-to-back spacewalks will begin early Sunday morning. The goals of the mission are to install two new solar arrays, a new gyroscopic reaction wheel assembly to help the telescope move, or slew from target to target, and a new power distribution box to route electricity from the new solar arrays to Hubble's myriad subsystesm. The power control unit was not designed to be replaced in orbit and thus represents the most technically difficult - and riskiest - portion of the mission. The spacewalkers also plan to install a new camera to extend Hubble's reach into the cosmos and to attach an experimental neon gas refrigerator to an infrared camera that ran out of coolant earlier. This mission will be conducted in the deep overnight, with the spacewalks starting around 2 a.m. each day. The only exception is the third and most technically challenging EVA, which will begin one hour earlier. Landing back at the Kennedy Space Center is targeted for around 5 a.m. on March 11. This will be Columbia's 27th flight, its first launch since July 23, 1999, when a short circuit a few seconds after liftoff left the crew just one failure away from a premature engine shutdown. Since then, Columbia has undergone and extensive overhaul and structural inspections. "This has been an extensive down period for Columbia, probably the most extensive that we've done," said NASA test director Steve Altemus. "This orbiter went through the most extensive wiring inspection and modifications of any of the orbiters, so that gives us high confidence we've got the vehicle working properly with respect to wiring. "We've got some upgrades that are going to improve safety and reliability and performance. This orbiter was taken apart and put back together in such a manner that we have nothing but the highest confidence it's going to perform like it always does on orbit, which is essentially flawless." The latest NASA television schedule and mission flight plan are posted below. A detailed mission overview will be posted here later today. =================================================================== Cold weather threatens launch; George Page dies (02/26/02) 10:30 a.m., 02/26/02, Update: Cold front threatens shuttle launch Unseasonably low temperatures behind an approaching cold front threaten to cause problems for Thursday's launching of the shuttle Columbia on a high-stakes mission to upgrade the Hubble Space Telescope. Forecasters say the temperature at 6:48 a.m. - the opening of Columbia's 66-minute launch window - may be as low as 39 degrees, just one degree above NASA's low-temperature safety limit for the expected conditions. The primary concern is the formation of ice on the shuttle's external fuel tank, which will be loaded with a half-million gallons of supercold liquid oxygen and liquid hydrogen rocket fuel. Chunks of ice breaking off and falling away during liftoff could damage the orbiter. But ice formation is not just a function of temperature. It also depends on humidity, wind speed and wind direction and, as one might expect with that many variables, the launch commit criteria in question is a bit complex. The flight rule in this case is built around a 35-minute clock that will start ticking when engineers begin pumping fuel into Columbia's external tank at 9:58 p.m. Wednesday. If the temperature limit for the observed weather is violated for 35 minutes in a row, and if forecasters do not see any chance for improvement, launch likely would be scrubbed. But if conditions "go green" at any point during a given 35-minute period, the clock is reset. Forecasters are predicting winds out of the northwest at seven knots with gusts to 10 knots at launch time. The temperature is expected to be 39 degrees with a relative humidity of 62 percent and the dewpoint at 27 degrees. Given those conditions, the shuttle would be "go" for launch. But if the temperature drops one degree lower than currently predicted and stays there for 35 minutes - and if all the other variables stay the same - the launch would be scrubbed. Given all that, forecasters are predicting a 60 percent chance of acceptable weather Thursday. Should launch be delayed 24 hours to Friday, the outlook improves to 80 percent "go." The forecast for a Saturday launch attempt calls for a 70 percent chance of bad weather as the frontal boundary moves back north over the space center. NASA's cold weather rules are a direct result of the 1986 Challenger disaster. Low temperatures affected the performance of critical rubber O-ring seals in Challenger's right-side solid booster, resulting in a catastrophic burn through that destroyed the orbiter. Post-Challenger boosters feature O-ring heaters and other improvements to make them less susceptible to low temperatures. The concern Thursday is primarily for ice formation on the external tank. But if launch slips to Friday, Columbia's boosters could be a factor. NASA's flight rules say if the average temperature is lower than 41 degrees for more than 24 hours going into a launch - long enough to lower the bulk temperature of the boosters' solid propellant below safety limits - launch must be scrubbed. At present, however, forecasters do not expect that rule to come into play. Out at launch pad 39A today, engineers ran into problems with ground equipment relief valves that forced them to delay loading hydrogen and oxygen into the shuttle's fuel cell power system. NASA test director Pete Nickolenko said the valves were replaced and that engineers will make up the lost time during normal "holds" in the countdown. Otherwise, there are no technical problems of any significance and liftoff remains on track for Thursday morning. Weather permitting! 01:20 p.m., 02/26/02, Update: Low-temperature guidelines chart Readers interested in NASA's temperature-related launch commit criteria might find the attached Cold Temperature LCC Table of interest. The chart shows what combination of wind, temperature and relative humidity permit a shuttle launch. Wind speeds, in knots, make up the vertical axis while the temperature makes up the horizontal axis. The values in the table cells refer to relative humidity, in percent. In those boxes, if the humidity is equal to or greater than the value shown, the shuttle is "go" for launch. 05:15 p.m., 02/26/02, Update: George Page, first shuttle launch director, dies George F. Page, the first space shuttle launch director, former deputy director of the Kennedy Space Center and a legendary missileman who played a key role in America's race to the moon, died today in Cocoa Beach after a long illness. He was 77. A 1952 graduate of Penn State University and a diehard Nittany Lions fan, Page was the man in charge of the countdown on April 12, 1981, when the orbiter Columbia rocketed away from pad 39A on the first space shuttle flight. It was a moment of high drama as the winged spaceship vaulted away from its seaside pad atop an incandescent stream of fire, shaking the ground for miles around as the unfamiliar roar of its twin solid-fuel boosters crackled across the Cape. Years later and long retired from NASA, Page said he wasn't sure exactly what was going to happen when that first countdown hit zero. But he said he never doubted the end result of the skill and integrity of the thousands of men and women who designed and built the world's first reusable spacecraft. Known for his strictly business, no-nonsense approach to management, Page was widely respected - and no doubt feared - by many of those same technicians and engineers. He was surprisingly modest about his own achievements, dismissing with a smile and perhaps a wisecrack any attempt to glorify his role in America's space program. But anecdotes about Page's firm control over the launch team abound and he remains one of the most respected figures in the history of the Kennedy Space Center. "George is a legend," said David King, director of shuttle operations at the Kennedy Space Center. "He was an incredible personality as well as just a brilliant person. In the early days of the shuttle, I recall lots of meetings with George. He was a very, very challenging person. He took you on and he expected a lot. "He was the kind of guy who, I think, we stand on the shoulders of today, clearly. He got us to the point we're at today by working awfully hard, asking all the right questions and challenging people to do their best. It's a great loss for the space program." Watching over the launch team from his glassed in office high above the firing room, Page seemed to have a sixth sense about the ebb and flow of shuttle processing, maintaining strict discipline and demanding the same from his team. Observing some departure from that discipline, Page was famous for barking out a public command or query and heaven help the engineer who failed to have a good answer. Many of those engineers hold senior management positions today and to a man, they fondly recall Page's legendary persona. "He ran the firing room with an iron hand and he expected everybody to demand the same of themselves as he did of himself. And he expected no less," said Tip Talone, now director of space station processing at the Florida spaceport. "George was universally respected for the very fact that he didn't allow for failure and he didn't allow for anybody not to feel the same religious-like fervor for humans in space that he felt. And that helped everyone step up to the plate." Said Gene Nurnberg, a long-time colleague and a close personal friend: "If there ever was a guy who led by example, it was George Page. He would ask you to do the impossible and then he'd be out there doing it himself. You really have to go back to Apollo, even before. He was the catalyst who made all that happen and set us up to do shuttle." Commander John Young and pilot Robert Crippen, who made the first trip into orbit aboard Columbia and who, in a very real sense, entrusted their lives to Page, certainly agreed. "It's a great honor for me to know George," Young said at Page's 1984 retirement from NASA. "We've been associated with a lot of programs. And in every one in which I've participated, he's always had a stake in my future. I was strapped to some vehicles and my whole future depended on it! He's the best." Former KSC Director Dick Smith said Page had left his mark "on every major program we've had at the center. You've done a truly outstanding job on everything you've ever attempted and you leadership in preparing the orbiter Columbia on its first launch has to stand as one of the most significant contributions to a major national program every made by an individual at KSC." Page ended his retirement dinner by remarking that he was "a fantastically lucky person to have had the career I've had, to have been in the right place at the right time." "I realize more than anybody else that any measure of success I've had has been because of the hard work and dedication of an awful lot of people, mostly the types right here in this room," he told a throng of colleagues and well wishers. "I want to thank you all for the wonderful day I've had today. I had a great career and I may have a couple of good years left in me yet." Page was born May 29, 1924, in Pittsburgh, Penn., and attended school in the Harrisburg area. He served in the U.S. Army Air Corps during World War II and then enrolled at Penn Sate University, where he earned a degree in aeronautical engineering in 1952. He was given the Distinguished Alumni Award in 1982 following launch of the first shuttle mission. Following graduation, Page spent five years as a launch operations engineer with General Dynamics and six years as a flight test engineer with Westinghouse. While serving as an assistant test conductor for General Dynamics, Page participated in all seven Mercury missions, helping American astronauts make their first tentative steps into low-Earth orbit. In June 1963, Page joined NASA as a spacecraft test conductor for the two-man Gemini vehicles that played a central role in perfecting the techniques that later would be used to reach the moon. He quickly moved up through the NASA hierarchy, serving as chief spacecraft test conductor for Gemini and Apollo launch operations and chief of the spacecraft operations division for Apollo, the Skylab space station project and the Apollo-Soyuz Test Program. Other titles included director of expendable vehicles operations, director of cargo operations and director of shuttle operations. In that position, Page served as the launch director for the first three shuttle flights. "He was a perfectionist and he wanted everybody who worked with him to be a perfectionist also," recalled Hugh Harris, former director of public affairs at the Kennedy Space Center. "And as a result, he really cracked the whip and told people 'here's what you've gotta be doing.' But he cared tremendously about the program and he was probably the ideal choice as the first launch director for the shuttle." In 1982, Page was named deputy director of the Kennedy Space Center. Following his retirement in 1984, he worked for Lockheed Martin in Florida and at Vandenberg Air Force Base in California and later served as a consultant for Analex Corp. He retired in the early 1990s to spend more time with his family and friends, taking great delight in golfing and talking his companions into giving up more strokes on the first tee than relative talents might merit. Page was awarded the NASA Distinguished Service Medal in 1975 for his role in the Apollo-Soyuz Test Project and again in 1981 in recognition of his service as the first shuttle launch director. He also held two NASA Exceptional Service Medals for his contributions to the Apollo 8 mission and the Apollo 11 landing on the moon. In 1982, he was awarded the Presidential rank of Distinguished Senior Executive. Page is survived by his wife Lois of Cocoa Beach; his sister Jane Hassler of Beaufort, N.C.,; his first wife, Dorothy, and their three children: Steven George Page of Palmdale, Calif., and his children Matthew and Diana; Janet Page Jones of Wilmington, N.C., and her children Andrew and Allison; and Viki Page Atkinson of Suntree, Fla., and her children Page and Scott. In lieu of flowers, the family requests donations be made to Health First Hospice. 05:30 p.m., 02/26/02, Update: NASA engineers troubleshoot wheel bearing issue NASA managers are studying a possible issue involving the shuttle Columbia's main landing gear wheel bearings. While the orbiter has been tentatively cleared for launch Thursday, weather permitting, engineers are researching test records to determine if the bearings were subjected to required tests and inspections. An update will be posted here when more details are available. =================================================================== Launch delayed 24 hours by predicted low temps (02/27/02) 10:00 a.m., 02/27/02, Update: Cold weather, suspect bearings cloud shuttle launch Cold weather behind a cold front and concern about suspect bearings in the shuttle Columbia's main landing gear continue to cloud NASA's prospects for launching the veteran orbiter early Thursday on a Hubble Space Telescope servicing mission. Forcasters are now predicting a low overnight temperature of 38 degrees at 6:48 a.m. - the opening of Columbia's 66-minute launch window - which is the lowest temperature allowable given the predicted winds and humidity. Freezing weather is predicted for Melbourne, Fla., just to the south of the space center and forecasters say Orlando and Daytona Beach could experience record lows. Engineers plan to begin fueling the shuttle around 9:30 p.m., assuming NASA's mission management team gives them permission. Depending on the updated forecast and the results of last-minute engineering tests to resolve the wheel bearing issue, Columbia's launch could be delayed before fueling even begins. The wheel bearing issue cropped up Tuesday during a final launch readiness review. Eight bearings in Columbia's main landing gear were part of a lot that were heat treated at 300 degrees instead of 500 degrees as required. Three engineering teams are reviewing data today and carrying out tests to determine whether such bearings can perform normally under the tremendous loads of a shuttle touchdown. The bearings cannot be replaced or even inspected at the launch pad. Should mission managers decide the problem must be corrected, NASA would have no choice but to haul the shuttle back to its hangar for repairs, a move that would delay launch indefinitely. As of this writing, there's no way to predict how this one will turn out. NASA spokesman George Diller said the results of the engineering reviews will be presented to the mission management team at this evening's tanking meeting. Stay tuned! 01:55 p.m., 02/27/02, Update: Wrong bearings installed aboard Columbia Engineers say a handful of wheel bearings in the shuttle Columbia's main landing gear are not the bearings specified in design drawings. The eight bearings in question have a slightly different shape and have a slightly different "footprint" their races. Engineers are racing the clock to determine whether Columbia can be safely launched Thursday with the wrong bearings in place. The issue cropped up in late January during routine space shuttle landing gear tire testing at Wright-Patterson Air Force Base. The bearings performed properly during a simulated abort landing but after a second test run, with 20 percent higher "loads," inspections revealed a cracked bearing. Engineers later discovered the bearing in question was not the type required for the main landing gear. Along with a slightly different conical apex, the bearings were heat treated at a lower temperature than the bearings normally used in shuttle landing gear. Reviewing paperwork, engineers determined that eight of these bearings had somehow made it into Columbia's main landing gear races. Two such 80-bearing races are in place in each main landing gear. Because the bearing in question stood up to a severe simulated abort landing and suffered a relatively benign failure in the subsequent test run, engineers are hopeful Columbia can be cleared for launch as is. But a final decision is not expected until mission managers meet this evening prior to fuel loading. 03:20 p.m., 02/27/02, Update: Launch delayed for 24 hours NASA managers have decided to delay the shuttle Columbia's launch for 24 hours, from Thursday at 6:48 a.m. to Friday at 6:22 a.m., because of low temperatures behind a cold front that are expected to be right at NASA's safety limit. Engineers also are troubleshooting an issue with bearings in the shuttle's main landing gear, but that concern did not play into the decision to scrub Thursday's launching. Forecasters predict an 80 percent chance of good weather Friday, with warmer temperatures. An updated flight plan will be posted below shortly. 04:20 p.m., 02/27/02, Update: Spacewalks now occur on weekdays The shuttle Columbia will have two "panes" in its launch window Friday. The first pane will open at 6:22:02 a.m. and close at 06:27:24 a.m. The second pane opens 10 seconds later at 6:27:34 a.m. and closes at 7:23:52 a.m. For the statistically minded, Columbia's liftoff will now be considered a night launch (sunrise is at 6:49 a.m.). A revised flight plan reflecting the 24-hour launch delay is posted below. Here are mission highlights at a glance in mission elapsed time and EST: EST........DD...HH...MM...EVENT 03/01/02 06:22 AM...00...00...00...STS-109 launch 01:22 PM...00...07...00...Crew sleep begins 09:22 PM...00...15...00...Crew wakeup 03/03/02 02:01 AM...01...19...39...TI rendezvous rocket firing 04:14 AM...01...21...52...HST grapple and berthing (364 sm by 348.5 sm) 08:12 AM...02...01...50...HST solar array retraction 03/04/02 01:27 AM...02...19...05...Spacewalk-1: Airlock egress 02:32 AM...02...20...10...Spacewalk-1: Solar array installation 07:52 AM...03...01...30...Spacewalk-1: Airlock repressurization 03/05/02 01:27 AM...03...19...05...Spacewalk-2: Airlock egress 02:07 AM...03...19...45...Spacewalk-2: Solar array installation 07:57 AM...04...01...35...Spacewalk-2: Airlock repressurization 03/06/02 12:27 AM...04...18...05...Spacewalk-3: Airlock egress 12:52 AM...04...18...30...Spacewalk-3: PCU replacement work begins 07:22 AM...05...01...00...Spacewalk-3: Airlock repressurization 03/07/02 01:27 AM...05...19...05...Spacewalk-4: Airlock egress 01:52 AM...05...19...30...Spacewalk-4: Advanced Camera work begins 07:52 AM...06...01...30...Spacewalk-4: Airlock repressurization 03/08/02 01:27 AM...06...19...05...Spacewalk-5: Airlock egress 01:52 AM...06...19...30...Spacewalk-5: NICMOS cryocooler work begins 07:52 AM...07...01...30...Spacewalk-5: Airlock repressurization 03/09/02 05:02 AM...07...22...40...HST is released from the shuttle 07:42 AM...08...01...20...Media crew interview 03/10/02 07:52 AM...09...01...30...Media crew interview 03/11/02 12:27 AM...09...18...05...Crew news conference 03/12/02 03:25 AM...10...21...03...Deorbit burn (rev. 164; dV: 468.2 fps) 04:35 AM...10...22...13...Landing (rev. 165) 07:25 p.m., 02/27/02, Update: Engineers defer final bearing decision Shuttle engineers trying to resolve lingering questions about bearings in the space shuttle Columbia's main landing gear met this evening to review data and decided to defer making a final decision on whether the orbiter can be safely launched as is. Additional meetings were scheduled for Thursday and while officials are optimistic the issue will be resolved in favor of a Friday launch, "we're not quite there yet," said a NASA spokesman. See the 1:55 p.m. update below for additional details. =================================================================== Revised TV sked released (02/28/02) 07:25 a.m., 02/28/02, Update: Engineers defer final bearing decision Revision A of the NASA television scheduled, released late Wednesday to reflect the shuttle Columbia's 24-hour launch delay, included multiple errors and as such, it has been deleted from this page. Revision B is expected later this morning. In the meantime, interested readers should note that the Mars Odyssey "first results" news briefing remains on schedule for Friday, not Saturday as indicated in the rev. A TV schedule. =================================================================== Columbia blasts off; coolant problem assessed (03/01/02) 03:00 a.m., 03/01/02, Update: Shuttle Columbia fueled for flight With the shuttle Columbia fueled for launch, the ship's seven astronauts began strapping in shortly after 3 a.m. to await liftoff on a dramatic mission to upgrade the Hubble Space Telescope. The launch window opens at 6:22:02 a.m. and closes at 7:23:52 a.m. There is a 10-second "cutout" between 6:27:24 a.m. and 6:27:34 a.m. when the shuttle cannot launch. There are no technical problems of any significance at pad 39A and the weather appears favorable. Forecasters are, however, monitoring clouds over the Kennedy Space Center and there's a chance that a broken deck of clouds below 8,000 feet could form that would violate NASA's safety rules. But as of this writing, the weather is "go" for launch. Commander Scott Altman, pilot Duane Carey, flight engineer Nancy Currie and spacewalkers John Grunsfeld, Richard Linnehan, James Newman and Michael Massimino headed for the pad around 2:45 a.m. Wearing their bright orange pressure suits, all seven appeared relaxed and in good spirits as they departed crew quarters. 05:20 a.m., 03/01/02, Update: Launch team monitors clouds The shuttle Columbia's countdown continues to tick smoothly toward launch at 6:22:02 a.m. The only issue is the weather, with forecasters monitoring the development of low clouds over the Kennedy Space Center. NASA flight rules forbid a launch if a broken deck of clouds develops below 8,000 feet. As of this writing, it appears that threat could become a reality, but launch managers are hopeful about finding a break in the cloud cover at some point during Columbia's 62-minute launch window. 06:35 a.m., 03/01/02, Update: Columbia rockets into space Fresh from a $100 million overhaul, the veteran shuttle Columbia roared back into space today on a high stakes mission to upgrade the Hubble Space Telescope's aging power system and to install a new camera to extend its scientific reach. Lighting up the pre-dawn sky like an artificial sun, Columbia's twin solid-fuel boosters ignited with a ground-shaking roar at 6:22:02 a.m., instantly pushing the veteran spaceplane away from pad 39A to kick off the 108th shuttle mission, the fourth devoted to Hubble servicing. Knifing through a thin layer of clouds just over the launch pad, Columbia put on a spectacular show, lighting the clouds from above as the Hubble Space Telescope sailed across central Florida at five miles per second, a clearly visible target 360 miles up. Strapped in on Columbia flight deck were commander Scott Altman, pilot Duane Carey, flight engineer Nancy Currie and payload commander John Grunsfeld. Seated below on the shuttle middeck were James Newman, Richard Linnehan and Michael Massimino. This was Columbia's first launch since July 1999 when the orbiter suffered a short circuit seconds after liftoff that left the ship one failure away from a premature engine shutdown. Since then, NASA's oldest shuttle has undergone extensive structural inspections, wiring repairs and upgrades, including installation of a state-of-the-art "glass cockpit" with flat panel color displays. "This has been an extensive down period for Columbia, probably the most extensive that we've done," said NASA test director Steve Altemus. "This orbiter was taken apart and put back together in such a manner that we have nothing but the highest confidence it's going to perform like it always does on orbit, which is essentially flawless." And so, after a one-day delay because of predicted cold weather, Columbia rocketed away today through a partly cloudy sky. No problems were reported during its fiery ascent. If all goes well, Altman will guide Columbia to a rendezvous early Sunday morning and Currie, operating the ship's robot arm from the aft flight deck, will mount the 24,000-pound observatory on a rotating service platform at the back of the shuttle's cargo bay. After switching Hubble to shuttle power, the telescope's two flexible solar arrays will be rolled up and the stage will be set for the most complex orbital servicing missions ever attempted by NASA. During five back-to-back spacewalks by alternating two man teams, the astronauts first will overhaul Hubble's electrical system, installing two smaller-but-more-powerful solar arrays and a replacement power control unit, the telescope's main electrical distribution system. The also will install a new reaction wheel assembly, a device used to help move Hubble from target to target. Once the electrical work is complete, the astronauts will turn their attention to the scientific objectives of Servicing Mission 3B, installing the Advance Camera for Surveys during the fourth spacewalk and a high tech refrigerator during the fifth to revive a dormant infrared camera. All of the work is challenging, but it is the power control unit swap out that will keep NASA managers - and astronomers around the world - on the edges of their seats. The 160-pound black box has suffered internal failures in recent years that have reduced its efficiency. And one internal glitch, should it get worse, could cause some of Hubble's batteries to overheat, triggering a catastrophic failure. But the PCU was not designed to be serviced by astronauts wearing thick spacesuit gloves. It is wired into Hubble's electrical system by 34 closely spaced, hard-to-reach cable connectors along its left side. Two more cables are connected at the base of the unit. "What makes it difficult is, as you're facing the PCU, those connectors are on the left-hand side, they're not staring right at you, they're on the left face," Grunsfeld said. "And that's on the side that that bay door is hinged. For the suited crewman to reach his hand in there, he's pretty much reaching in there blind. "I kind of equate it to changing out spark plugs on your car," he said. "There's always those spark plugs down there where you sort of can't see real well, you've just got to go down and feel and make sure you're oriented such that you're unscrewing it without a lot of offset force." Adding to the drama - and the risk - of the PCU swap out, Hubble must be completely powered down and its batteries disconnected before the work can begin. The new PCU must be in place and power restored within the next 10 hours or so or the low temperatures of space could damage Hubble's sensitive electronics. Anne Kinney, director of astronomy and physics at NASA headquarters, said she will be "nervous as hell" until the repair work is complete. Ed Weiler, associate administrator for space science, said the PCU replacement "scares me a lot." "It kind of violates a long-standing policy in the space business that if something's working well you don't turn it off and just hope it comes back on," he said. "We're not doing that cavalierly, we fully anticipate that everything will work just fine," he added. "But it is a risk that we've never faced before. So this mission is no cakewalk." While the PCU replacement is the top priority of Columbia's mission, it will not be attempted until the third spacewalk. First, Grunsfeld, Linnehan, Newman and Massimino will install the new solar arrays and control circuitry that will give engineers more control over Hubble's power system before the PCU replacement is attempted. The first spacewalk, by Grunsfeld and Linnehan, is scheduled to begin around 1:30 a.m. Monday. The second, by Newman and Massimino, will begin at the same time Tuesday. Along with installing the second solar array, Newman and Massimino will install the new reaction wheel toward the end of the second spacewalk. During both excursions, the astronauts will install thermal shields and light shades over sensitive areas of the telescope that will help protect the observatory during the PCU power outage. The PCU replacement, by Grunsfeld and Linnehan, is expected to take at least seven-and-a-half hours. Assuming the work goes smoothly, Newman and Massimino will install the Advanced Camera for Surveys next Thursday during the fourth spacewalk. The fifth and final outing is installation of a high-tech "cryocooler" refrigerator to revive the dormant Near Infrared Camera and Multi-Object Spectrometer, or NICMOS. The NICMOS instrument is sensitive to infrared light but it must be chilled to less than 100 degrees above absolute zero to work properly. The instrument was launched with a dewar of nitrogen ice coolant. But an internal "thermal short" caused the nitrogen to sublimate away faster than expected. The experimental cryocooler that will be installed by Columbia's crew uses neon gas and three small turbines spinning at 400,000 rpm to provide cooling to 75 degrees above absolute zero. Installation of the cryocooler is perhaps the single most complex task on the mission from a spacewalk perspective, but given the experimental nature of the device, it is considered the lowest priority of the flight. 11:00 a.m., 03/01/02, Update: Engineers study coolant flow problem Flight controllers are troubleshooting apparent problems with one of the Freon coolant loops used to carry away heat generated by the shuttle Columbia's electronics systems. While the trouble has not yet had any impact on Columbia's mission to upgrade the Hubble Space Telescope, NASA's mission management team plans to meet late today to discuss the issue. Columbia's crew, meanwhile, has completed its post-launch work to rig the space shuttle for orbital flight. Other than a bit of trouble coaxing the shuttle's inner airlock hatch open, the astronauts have not had any major problems. Following a short rocket firing to fine tune their approach to Hubble, the astronauts plan to call it a day and go to bed around 1:22 p.m. They will be awakened at 9:22 p.m. to begin their first full day in orbit. The shuttle's ascent today was virtually flawless. But just before the ship's cargo bay doors were opened, when coolant loop radiators on the inner side of each door were still being bypassed, data indicated the flow of coolant through one loop was sharply reduced. Once Columbia's cargo bay doors were opened and Freon-21 began flowing through a radiator in the left-side payload bay door, the cooling rate returned to normal. But the reduced flow presumably will show back up when the cargo doors are closed for landing and the radiators are once again in bypass mode. From that point forward, the heat carried away by the Freon-21 must be dissipated by boiling water or, depending on the shuttle's altitude, ammonia. NASA flight rules require a minimum coolant flow rate of 211 pounds of Freon-21 per hour in each coolant loop. Just before Columbia's cargo bay doors were opened today, engineers saw the flow rate in one loop drop to near the flight rule redline. The shuttle must have active cooling for re-entry. To protect against the possibility of a second failure, NASA's flight rules call for landing at the earliest U.S. opportunity if one of the coolant loops is declared failed. That's not the case here, but with a flow rate so close to the redline, NASA's mission management team plans to meet at 6 p.m. this evening to discuss the problem and possible workarounds. While there is no mission impact at present, this is an issue that will bear watching over the next few days. 12:30 p.m., 03/01/02, Update: Astronauts briefed on coolant problem NASA managers assessing the impact of an apparent blockage in Freon coolant loop No. 1 aboard the shuttle Columbia told the crew to press ahead with their normal timeline while engineers study the problem. The astronauts are preparing to go to bed at 1:22 p.m. Astronaut Steve MacLean in mission control told the crew NASA's mission management team will meet at 6 p.m. to discuss the coolant problem and that they can expect a full report when they're awakened at 9:22 p.m. this evening. "We on the ground are looking at the degraded flow in Freon loop 1 and at present we are pressing on with the nominal timeline," MacLean said. "However, there is an MMT at 5 p.m. (Central time) when they will discuss the details and impacts of the degraded flow. So first thing in the morning (i.e., crew wakeup tonight), we'll give you the outcome of their discussions and we're all hoping that we can rendezvous with the Hubble and fix it." See the 11 a.m. status report immediately below for complete details. 07:45 p.m., 03/01/02, Update: NASA managers optimistic about full-duration mission NASA managers are "very optimistic" the shuttle Columbia's mission to service the Hubble Space Telescope can continue as planned, despite a reduced flow of Freon in one of two critical coolant loops that keep the ship's electronics systems from overheating. NASA's mission management team met this evening to assess the impact of the degraded flow in coolant loop No. 1. After reviewing telemetry from the shuttle, they decided to defer making any final decisions until after a second meeting Saturday afternoon. In the meantime, Columbia's mission will continuing per the flight plan and despite speculation in the media that the mission might be terminated early, shuttle program manager Ronald Dittemore said he's confident the engineering analysis will prove the orbiter can safely fly a full-duration mission. "Our MMT meeting that we just concluded agreed that we would continue the mission for the next 24 hours while we continue to review data and look at our processing records and modification records to see if there's anything that we can determine might be unusual in the status of these two Freon loops," he said shortly after 7 p.m. At first blush, he added, engineers were concerned Columbia's flight might have to be cut short - before the crew could even begin servicing the space telescope - because of NASA flight rules that require a quick landing in the event of a coolant loop failure. The shuttle is equipped with two coolant loops that circulate Freon-21 through radiators or, during launch and landing, through water or ammonia boilers, to carry away the heat generated by the ship's myriad electronics systems. Without active cooling, the shuttle's electrical systems, including flight computers and other critical avionics boxes, would overheat and suffer potentially catastrophic damage. While the shuttle can safely fly with just one operational coolant loop, the flight rules require a quick landing in the event of a single failure because of the possibility of a second malfunction that could take out the one working loop. The problem under discussion today does not affect Columbia in its current orbital configuration. It would only be an issue during landing, when the shuttle's cargo bay doors are closed for entry and the ship's radiators are not available for cooling. The reduced flow through coolant loop No. 1 involves a different system that is used when the radiators are stowed and bypassed. The problem cropped up just before the payload bay doors were opened 90 minutes after launch. Flight controllers noticed a sharp drop in the flow of Freon through loop No. 1, indicating possible blockage in a line. The flight rule calls for a minimum flow rate of 211 pounds of Freon per hour and the observed flow rate was very close to that flight rule redline. "Not knowing anything more about the degradation and not understanding and reviewing all the data at that time, they alerted everybody it might have a mission impact, it could have the potential of affecting us in such a way that we might have to terminate the mission early," Dittemore said. "Since those early minutes after launch, we have concluded that is not the case, we are not in a condition where we have to come home early at this time. Our initial looks at the system show it to be stable, even with the degradation, and we believe we are safe to continue on orbit for the next 24 hours while we continue to look at further information and to refine our analysis. "This analysis, we firmly believe, will conclude we are safe to continue the mission for the full duration. We just need the time to make sure we dot all the i's and cross all the t's to be positive about that conclusion." He added that he is "very optimistic" about the eventual outcome. "When we first heard about the degradation, it looked a little gloomy at that time, especially since we'd had such a great launch. But now that we've learned a little bit more about it and all the teams have reviewed it ... we're very optimistic that we have a plan that will conclude tomorrow, I think, that we will be able to press on with the full mission duration." 10:20 p.m., 03/01/02, Update: Astronauts awakened for busy day in space The Columbia astronauts were awakened for their first full day in orbit around 9:22 p.m. They were updated by email from mission control that flight controllers had decided to defer making a final decision on what to do about the reduced flow of Freon in one of the shuttle's two coolant loops (see the 7:45 p.m. entry below for details). Pressing ahead with plans to rendezvous with the Hubble Space Telescope early Sunday, the astronauts face a busy day in orbit overnight to ready their spacesuits and tools for five back-to-back spacewalks to overhaul and upgrade the $2 billion observatory. Astronaut Nancy Currie will power up Columbia's 50-foot-long robot arm just before 1 a.m. to make sure the Canadian-built space crane will be ready for work during the Hubble spacewalks. After initial checkout, Currie will use cameras on the arm to survey Columbia's cargo bay and the lazy Susan-type servicing platform at the rear of the payload bay. Her crewmates, meanwhile, are scheduled to set up laptop computers and lower the shuttle's cabin air pressure from 14.7 psi to 10.2 psi. The lower pressure will help spacewalkers John Grunsfeld, Richard Linnehan, James Newman and Michael Massimino purge nitrogen from their bloodstreams before donning their 5 psi spacesuits. After lunch around 4:15 a.m., the astronauts will turn their attention to checking out their spacesuits and the scores of tools they will use to work on Hubble. Two rendezvous rocket firings are planned today, the first just after midnight and the second just after 9:15 a.m. Saturday. In addition, the crew will field questions from reporters with three news organizations beginning at 8:17 a.m. Today's mission status briefing is scheduled for 9 a.m. Here is the crew's updated flight plan as uplinked to the crew in their daily "execute package" of instructions from mission control (in EST and mission elapsed time): EST........DD...HH...MM...EVENT 03/01/02 09:22 PM...00...15...00...Crew wakeup 11:52 PM...00...17...30...Currie exercises 03/02/02 12:13 AM...00...17...51...NC2 rendezvous rocket firing 12:22 AM...00...18...00...MAGR setup 12:22 AM...00...18...00...HHL checkout 12:22 AM...00...18...00...Grunsfeld exercises 12:52 AM...00...18...30...Linnehan exercises 12:52 AM...00...18...30...Robot arm (RMS) powerup 01:07 AM...00...18...45...RMS checkout 01:22 AM...00...19...00...HST laptop computer configuration 01:37 AM...00...19...15...10.2 cabin depress 01:52 AM...00...19...30...RMS inspects Hubble support platform 02:22 AM...00...20...00...Altman exercises 02:52 AM...00...20...30...RMS payload bay survey 02:52 AM...00...20...30...Service platform prepped for Hubble berthing 03:37 AM...00...21...15...Massimino exercises 04:17 AM...00...21...55...Crew meals begin 05:32 AM...00...23...10...Airlock preparations 05:32 AM...00...23...10...Robot arm powerdown 05:47 AM...00...23...25...Rendezvous tools checkout 06:02 AM...00...23...40...Spacewalk tools checkout 06:02 AM...00...23...40...Spacesuit checkout (3,4) 06:52 AM...01...00...30...HST ground command: Solid state recorder playback 07:17 AM...01...00...55...Power grip tool checkout 08:17 AM...01...01...55...Crew interviews: WMAQ-TV, AP, Fox News Channel 08:17 AM...01...01...55...Spacesuit checkout (1,2) 09:00 AM...01...02...38...Mission status briefing on NASA TV 09:18 AM...01...02...56...NC3 rendezvous rocket firing 09:37 AM...01...03...15...REBA hardware checkout 10:42 AM...01...04...20...HST ground command: Solar arrays latched 12:52 PM...01...06...30...Crew sleep begins 01:00 PM...01...06...38...Mission highlights reel on NASA TV 03:02 PM...01...08...40...HST ground command: Solar array brakes on 04:02 PM...01...09...40...HST ground command: Retract high gain antennas 08:52 PM...01...14...30...Crew wakeup =================================================================== Columbia cleared for full-duration mission (03/02/02) 09:50 a.m., 03/02/02, Update: Mission managers still 'cautiously optimistic' about cooling problem NASA managers are increasingly optimistic problems with one of the shuttle Columbia's two coolant loops will not force an early end to a dramatic mission to overhaul the Hubble Space Telescope. "The analysis and the discussions thus far are such that people are feeling more and more optimistic about the prospects of remaining on orbit and continuing the flight nominally," astronaut Mario Runco told the astronauts early today. "The discussion is still on going and as you know and would have expected, people are sharpening their pencils and taking a real close look at this. "The mission management team is going to meet at noon (CST) today and that is when a final decision will be made, one way or the other. But again, I'd like to couch this in a more optimistic light. That is the nature of the discussion at this point, it's just that a final decision has not been reached at the present time." "I appreciate you putting those words together for us," replied commander Scott Altman. "We will stand by for the final decision." Shortly after launch Friday , one of the shuttle's two main Freon coolant loops suffered a reduced flow rate, dropping to just above NASA's flight rule redline of 211 pounds of Freon-21 per hour. Shortly thereafter, the shuttle's cargo bay doors were opened and the Freon in loop 1 was routed through radiators in the port-side payload bay doors. The flow rate dropped again, due to the increased volume, but this isn't an issue for on-orbit operations, when many of the avionics systems used for re-entry are powered down. It's a different story for landing, however, when the radiators are stowed and the heat generated by the shuttle's electronics must be rejected by boiling water or ammonia. The redline in question reflects the ability of coolant loop 1 to cool electronic gear in an aft avionics bay housing equipment that must be powered up for entry. To protect against the possibility of problems with the second coolant loop, NASA flight rules require a quick landing if the flow rate in either loop falls below about 211 pounds of Freon-21 per hour when the radiators are not deployed. Before Columbia's cargo bay doors were opened Friday, the flow rate in this "rad bypass mode" hit 195 pounds per hour, in technical violation of the flight rule. The flight rule does not apply to flow rates when the radiators are deployed. Lead flight director Bryan Austin said today engineers believe the flow rate in loop 1 is stable, i.e., it won't get much worse in rad bypass, and that loop 2 appears healthy. Engineers are justified in re-assesing a pre-defined flight rule, he said, to reflect the real-world conditions aboard Columbia. As for the wisdom of changing flight rules on the fly during the heat of a very important mission, Austin said "sometimes in the real world it doesn't always line up exactly how you wrote it down - if this happens, then we'll do this - and what we're taking is a real-world scenario and then bringing a flight rule up to date." "The assumptions bethind that flight rule will not change at all," he said. "What we're doing is bringing them up to date in terms of how we're operating the vehicle ... so the actual end item number will change, but the assumption, which is truly the foundation of the rule, will not change at all." Regardless of the redline limit vs the actual flow rate, engineers say loop 1 provides sufficient cooling to permit a normal entry if it doesn't get worse. And engineers do not think it will. They believe the reduced flow is the result of a small bit of debris lodged in an internal Freon-line filter. They also believe that if any similar debris was present in loop 2 it would have shown up by now. So far, loop 2 is operating normally. Before a round of media interviews this morning, Altman asked Runco for an update on the cooling issue. "The flow rate on loop 1 is sufficient to support an entry," Runco replied from Houston. "The main focus of attention right now is the integrity of Freon loop 2. The concern is it having the same problem as Freon loop 1 because of all the work that has been done." Columbia, NASA's oldest space shuttle, is making its first flight in two-and-a-half years following a $100 million overhaul and upgrade of its own. The problem with coolant loop No. is believed to be debris lodged in one of the Freon lines. Fielding questions from reporters, Altman and payload commander John Grunsfeld said they were too busy preparing for the upcoming work on the Hubble Space Telescope to spend much time worrying about the impact of the coolant loop issue. "We've been extremely busy up here (and) we haven't had a lot of time to ponder that," Grunsfeld said. "Of course, we do know that it's a serious problem back there and one that shouldn't be ignored and so we're letting the smart folks on the ground really worry for us. If we had to come back, we know that Hubble's important enough that Hubble would be well taken care of." The astronauts spent their first full day in orbit readying Columbia and its robot arm for the rendezvous and capture of Hubble early Sunday. They also have readied the shuttle's airlock for the upcoming spacewalks and are in the process of checking out the four spacesuits that will be used in five back-to-back EVAs beginning around 1:30 a.m. Monday. So far, no problems of any significance have been encountered. 03:30 p.m., 03/02/02, Update: Shuttle Columbia cleared for full-duration flight As expected, NASA's mission management team today formally cleared the shuttle Columbia's crew to press ahead with a full-duration mission to repair and upgrade the Hubble Space Telescope. The decision was made after engineers were able to show that reduced flow in one of Columbia's two coolant loops was still sufficient to support a normal end-of-mission landing even if the second, healthy coolant loop failed. "The decision of the management team is we have the confidence that Freon coolant loop 2 is good and stable and that the (degraded) flow rate that we see in Freon coolant loop 1 is large enough that it would be able to support a full nominal entry if called upon to do it all on its own," said shuttle program manager Ronald Dittemore. "And so the team decided that we would press on with the nominal mission and not make any changes." Dittemore said engineers believe the blockage in coolant loop 1 is caused by debris that shook loose during the "shake, rattle and roll" of ascent and lodged in a downstream filter. If there was any similar debris in loop 2, it would have shaken loose during the same period. The fact that loop 2 continues to function normally gives engineers confidence no such problems will affect it later. "If there's anything in loop 2 it would have broken loose by now," Dittemore said. "Since it passed that screen, we feel highly confident it will remain that way." As mentioned below, the problem does not affect Columbia's systems when it is configured for normal orbital operations with its payload bay door radiators deployed. The issue is the performance of loop 1 when the doors are closed. With the radiators stowed, and with additional electronic equipment turned on, the heat load in the shuttle's aft avionics bays is higher and the reduced flow rate in loop 1 is more of a factor. Even though the flow rate is slightly lower than allowable under NASA's conservative flight rules, a re-analysis of the actual heat loads aboard Columbia indicate loop 1 still has enough cooling capability to support a landing even if the currently healthy loop 2 should fail completely. Mission manager Phil Engelauf, in a teleconference with reporters, said most of NASA's flight rules were written before engineers had real world experience flying the space shuttle. As such, most are very conservative. He said after 107 shuttle missions, NASA now has an enormous database of actual in-flight experience and in this case, that experience gave engineers confidence the coolant loop redline could be safely relaxed somewhat. "The philosophy of the rule is, when one Freon loop can no longer support the heat loads for entry, you call it failed and you decide to come home next PLS (primary landing site) because you're down to one loop and if you lose that good loop you can't support the heat loads for entry," he said. "That's the philosophy of the rule. "Now, that's pretty hard to implement in real time because you need a number of what it takes to support the entry loads. Most of the rules we fly today in that six-inch-thick flight rule book have been on the books since before we started flying." At that time, he said, engineers considered the certification limits for the hardware, the results of testing and the predictions of mathematical modeling to determine how much Freon would need to move through the system to carry away the heat engineers calculated would be generated. The result was written into the flight rule governing the Freon coolant loops. "Well, we've got 107 flights of experience under our belts now," Engelauf said. "We've continued to evolve the math model, we've got performance history of the flight hardware that we didn't have before." The result is more accurate knowledge of how each shuttle actually performs in space, how much heat is actually generated and how much Freon flow is absolutely required. When engineers studied telemetry from Columbia, they saw numbers that were slightly below the printed redline. But after around-the-clock analysis, they concluded the flow rate was sufficient to cool Columbia during entry even if loop 2 failed outright. "And I would submit to you guys if we arbitrarily declared next PLS and aborted the mission for a very small violation of the rule, without going and looking at the real data to see if we couldn't do better than that, you guys would be all over us for not doing our jobs," Engelauf said. Columbia's crew went to bed before the mission management team met. They will be awakened at 9:22 p.m. After breakfast, they will get to work for the final stages of the shuttle's rendezvous with the Hubble Space Telescope. If all goes well, astronaut Nancy Currie, operating Columbia's robot arm, will grapple Hubble around 4:15 a.m. Sunday. 11:30 p.m., 03/02/02, Update: Columbia crew set for Hubble rendezvous The Columbia astronauts fired the shuttle's twin orbital maneuvering system rockets for three-and-a-half minutes this evening - slowing the ship down by about 225 mph - to kick off the final phase of the crew's rendezvous with the Hubble Space Telescope. If all goes well, commander Scott Altman will guide the veteran shuttle to a point directly below the 24,000-pound observatory at 4:13 a.m. Sunday. Astronaut Nancy Currie, operating the shuttle's robot arm, will then pluck Hubble out of open space and mount it on a rotating service platform at the back of Columbia's cargo bay. The rocket firing was the longest such maneuver ever carried out as part of an orbital rendezvous, but there were no problems and the crew is pressing ahead for an on-time rendezvous with Hubble. When the astronauts went to bed earlier Saturday they did not know for sure whether they would be allowed to attempt the rendezvous or their long-planned overhaul of the space telescope. Problems with one of Columbia's two Freon coolant loops raised fears Friday the mission might have to be cut short. But late Saturday afternoon, NASA's mission management team cleared the crew to press ahead with a full-duration mission after concluding the coolant loop in question could still support a normal end-of-mission landing. "WeÕre happy to say itÕs official now Ð the MMT has decided that you are GO to press on with the nominal mission," flight controllers told the astronauts in a morning message. "Freon loop 1 has remained stable ever since Rad Act (radiator activation). Even with the degradation, the flow rate in loop 1 has adequate margin to support full entry loads, in the case of a loop 2 failure. WeÕve seen no problems whatsoever with loop 2. Of course, we are carefully watching both Loops and any degradation in flow in either will be cause to reevaluate." Translation: If loop 1 suffers any additional reduction in coolant flow, or if loop 2 begins having problems, the mission likely will be terminated. In preparation for Columbia's arrival, ground controllers have shut Hubble's aperture door, retracted its two high-gain KU-band antenna and disengaged its solar array brakes. The shuttle will approach the telescope from behind and below, beginning the terminal phase of the rendezvous procedure from a point about 9.2 miles behind the target. "Rendezvous is really a very interesting dance, choreographed between us and the Hubble as we move up and slowly and yet surely, join up with it," Altman said in a NASA interview. "From launch until rendezvous, everything is planned and watched over by people on the ground and us in orbit as we do different burns, modifying our altitude so we can kind of catch up to Hubble by going faster in a lower orbit, and then bringing us up to the point where Hubble and I are both flying in formation 17,500 miles an hour, you know, five miles every second, and yet approaching very gently, apparently, until the point where it's hanging motionless over our payload bay and Nancy can use the robotic arm to just go out there, reach out, and grab it. And then we'll berth it in the back and go to work. "It is a very complicated task," Altman said. "And I'm glad we have a great support structure on the ground to help, with figuring out how to do the burns, how to choreograph this dance, really, to the point where we can see it out the window. From that point on, we're actually hand-flying the orbiter up to the final rendezvous. "You know, a lot of people think that the shuttle is always flown by computers and it's not as much of a hands-on flying task. And, in rendezvous that's certainly not true. You know, the computers get us close; but then we rely on the pilots to take us the rest of the way home until we can rendezvous and just be there in the same spot of space, flying formation around the Earth." Once Hubble is mounted on its servicing platform, three latches will engage to lock the telescope down and an umbilical will be extended to provide power from the shuttle's fuel cells. As viewed from Columbia's aft flight deck, Hubble's two solar arrays will appear face on to the left and right of the telescope's tube, which will extend straight out of the cargo bay. By convention, the left-side array, as viewed from the flight deck, is on the telescope's minus V2 axis while the right-side array is on the positive V2 axis. The arrays were installed during the first Hubble servicing mission in 1993. They weigh 339 pounds each and measure 40 feet long by 10.8 feet wide, delivering about 4,600 watts of power from silicon solar cells. Because of the wear and tear of temperature extremes and normal space radiation, the flexible panels now provide just 63 percent of their original power. In addition, they suffer from structural problems and some shorted circuitry in the wiring connecting all the solar cells. During the first two spacewalks of Columbia's mission, two new arrays will be installed that are heavier - 640 pounds per wing - and more powerful, generating some 5,270 watts. While heavier, they are smaller than Hubble's flexible panels, measuring just 23 feet long and 8.5 feet wide. The additional power generated by the new gallium arsenide solar cells will enable astronomers for the first time to operate all of Hubble's instruments at the same time for simultaneous multi-disciplinary observations. In addition, their smaller size will reduce the atmospheric drag that constantly acts to reduce Hubble's altitude. Before the new arrays can be attached, however, the old wings must be rolled up, a task that will be carried out Sunday about four hours after the telescope is captured. First, the astronauts, operating the servicing platform by remote control, will tilt Hubble forward and rotate it counter clockwise so the -V2 array is facing the crew cabin. Once that array has rolled up - the process is expected to take about eight minutes per wing - the telescope will be rotated 180 degrees clockwise to bring the +V2 array forward. There is a bit of uncertainty about whether the arrays will, in fact, smoothly roll back up. During the first servicing mission in 1993, a similar array jammed and failed to retract, forcing the astronauts to dump it overboard. Should Columbia's crew run into similar problems, spacewalkers John Grunsfeld and Richard Linnehan will simply jettison one or both arrays as required early Monday at the start of their first spacewalk. In addition, there's a slight chance brittle insulation surrounding he external framework of the arrays could flake off during the retraction procedure, creating a small cloud of dusty debris. But mission managers are optimistic the arrays will roll up as planned and even if a small amount of insulation does, in fact, flake off, Altman could simply move the shuttle away slightly, eliminating any chance of contamination. Here is a detailed timeline of today's activity based on revision D of the NASA television scheduled (posted below in full) and the latest flight plan revision uplinked to the astronauts in their morning Execute Package (in EST and mission elapsed time): EST........DD...HH...MM...EVENT 11:17 PM...01...16...55...Begin rendezvous timeline 11:22 PM...01...17...00...HST: Solar array slew 11:47 PM...01...17...25...EVA-1 tools configured 03/03/02 12:02 AM...01...17...40...Currie exercises 12:27 AM...01...18...05...NC4 rendezvous rocket firing 12:47 AM...01...18...25...Payload interrogater config 12:47 AM...01...18...25...Newman exercises 01:17 AM...01...18...55...Linnehan exercises 01:47 AM...01...19...25...Grunsfeld exercises 02:01 AM...01...19...39...TI rendezvous rocket firing 02:17 AM...01...19...55...Massimino exercises 02:47 AM...01...20...25...HST: Maneuver to capture attitude 03:12 AM...01...20...50...Robot arm (RMS) poised for capture 03:17 AM...01...20...55...HST in capture attitude 03:21 AM...01...20...59...R-bar arrival 04:13 AM...01...21...51...HST grapple and berthing (364 sm by 348.5 sm) 04:37 AM...01...22...15...HST latched to FSS 05:12 AM...01...22...50...RMS survey of HST/FSS 05:27 AM...01...23...05...HST: Switch to external power 06:07 AM...01...23...45...Altman exercises 06:22 AM...02...00...00...Middeck prepped for spacewalk 06:37 AM...02...00...15...Group B computer powerdown 06:37 AM...02...00...15...VTR playback of HST grapple. On NASA TV 07:02 AM...02...00...40...Carey exercises 07:07 AM...02...00...45...STS crew: Solar array retraction survey 07:27 AM...02...01...05...HST: Solar arrays slewed to 0 degrees 08:27 AM...02...02...05...HST: Solar array retraction 09:37 AM...02...03...15...HST: Solar array retraction 10:07 AM...02...03...45...RMS parked 10:22 AM...02...04...00...EVA review 11:00 AM...02...04...38...Mission status briefing. On NASA TV 12:22 PM...02...06...00...HST: KU-band checkout 12:52 PM...02...06...30...Crew sleep begins 01:00 PM...02...06...38...Video highlights reel begins airing on NASA TV 01:02 PM...02...06...40...HST: Battery discharge begins 08:52 PM...02...14...30...Crew wakeup =================================================================== Shuttle crew captures Hubble (03/03/02) 02:05 a.m., 03/03/02, Update: Terminal phase of Hubble rendezvous begins Commander Scott Altman fired one of Columbia's two orbital maneuvering system rockets for 11 seconds this morning to begin the terminal phase of the shuttle's rendezvous with the Hubble Space Telescope. At the time of the rocket firing, Columbia was about 9.2 miles behind the space telescope and closing in at roughly six miles per hour. The "TI" rocket firing was the final major burn in the rendezvous sequence, setting up a long-awaited grapple of Hubble by the shuttle's robot arm at 4:13 a.m. 05:35 a.m., 03/03/02, Update: Shuttle astronauts capture Hubble Space Telescope Astronaut Nancy Currie, a five-foot-tall helicopter pilot operating the shuttle Columbia's 50-foot-long robot arm, grappled the 24,000-pound Hubble Space Telescope early today and carefully mounted it atop a rotating service platform at the back of the shuttle's cargo bay. Flying 360 miles above the central Pacific Ocean, Currie locked onto the space telescope at 4:31 a.m. following a picture-perfect two-day rendezvous that began with Columbia's launching Friday. "Houston, we have Hubble on the arm," commander Scott Altman radioed when the robot arm's snares engaged a grapple fixture on the telescope. "Copy, Scooter, outstanding work," replied astronaut Mario Runco from mission control. "And there's a big sigh of relief we heard from Goddard all the way here." "I think it echoed up here as well," Altman said. They were referring to the Goddard Space Flight Center in Greenbelt, Md., where the Hubble Space Telescope is managed and where many of the tools and most of the equipment that will be used to repair and upgrade the observatory were developed. With Hubble safely on the end of Columbia's robot arm, Currie was in no hurry. After waiting for oscillations in the telescope's solar wings to damp out, she began slowly moving it down toward its service platform in the shuttle's cargo bay, taking a full hour to complete the trip. Along the way, spectacular television images were beamed down showing the telescope poised in front of Columbia's vertical stabilizer with a brilliant white Atlantic Ocean cloudscape passing by in the background. Finally, at 5:33 a.m., the third of three latches fully engaged, firmly locking Hubble to its servicing platform and completing the first step in this complex repair mission. Within the next hour, a motorized umbilical cable will be plugged into the base of the telescope to provide electricity from the shuttle in preparation for retraction of Hubble's two huge solar arrays later this morning, after its six internal batteries are charged up. 09:50 a.m., 03/03/02, Update: Space telescope's solar arrays retracted The Hubble Space Telescope's two aging solar arrays were successfully rolled up early today, setting the stage for installation of two smaller, more powerful panels during spacewalks early Monday and Tuesday by astronauts aboard shuttle Columbia. First, the telescope's rotating service platform was tilted forward and the observatory was rotated 90 degrees so the starboard solar array faced the astronauts looking on from Columbia's aft flight deck. The initial attempt to retract the starboard array failed, apparently because of problems with a microswitch in the retraction mechanism. But after commands were sent from the ground to reset the switch, the 40-foot-long, 10-foot-wide flexible solar wing rolled up normally with both halves wrapping up around the array's central mast. retraction began at 8:23 a.m. and was complete five minutes later. Hubble then was rotated 180 degrees to bring the port-side array into view and, after Columbia sailed back into sunlight, the procedure was repeated. Again, the array retracted smoothly. Mission managers were a bit concerned before launch that the arrays might not retract properly after seven-and-a-half years in the harsh environment of space. A similar array had to be jettisoned in 1993 when the current panels were installed. But to everyone's relief, there were no problems of any significance today. "And we've got a winner on both sides," astronaut Steve Maclean radioed the crew from mission control. "It's a good start to five more great EVAs." The only technical issue at present involves one of Columbia's three electricity producing fuel cells, which produce electricity by combining oxygen and hydrogen. Water is a byproduct of the reaction. Engineers are trying to figure out why one of the powerplants is producing slightly hydrogenated water. As of this writing, the water produced by that fuel cell is being isolated in a holding tank to prevent any from getting into the crew's supplies. But at present there's no impact on the mission. The Columbia astronauts have now successfully completed the first three steps necessary for Hubble's overhaul and upgrade: Capture of the 24,000-pound telescope; attachment of an umbilical to supply orbiter power; and retraction of both solar arrays. The stage is now set for the first of five back-to-back spacewalks Monday through Friday to upgrade Hubble's electrical system, to install a new, more powerful digital camera and to attach an experimental refrigeration system to revive a now dormant infrared camera-spectrometer. Installing new solar arrays, along with a new power control unit to route that electricity to Hubble's myriad subsystems, will enable the observatory's instruments to operate simultaneously for the first time, dramatically increasing the telescope's productivity while at the same time increasing its life expectancy. The old flexible solar arrays weigh 339 pounds each and generate about 4,600 watts of power from silicon solar cells. The solar wings that will be installed Monday and Tuesday weigh 640 pounds each. But they're smaller - just 23 feet long - and 30 percent more powerful, generating 5,270 watts using gallium arsenide solar cells. The first new solar panel will be installed by astronauts John Grunsfeld and Richard Linnehan during the crew's first spacewalk, scheduled to begin around 1:27 a.m. Monday. The second will be installed Tuesday by spacewalkers James Newman and Michael Massimino. 11:30 a.m., 03/03/02, Update: NASA managers elated with initial Hubble success NASA mission managers say today's capture of the Hubble Space Telescope and the retraction of its two solar arrays went by the book and that all systems are "go" for the first of five back-to-back servicing spacewalks early Monday morning. "It's a great day in space," said Wayne Hale, a senior flight director serving as NASA's mission operations representative for this flight. "We have the Hubble Space Telescope, which is probably the premier scientific instrument of our generation, berthed in the payload bay, ready to be refurbished and renewed and in five or six days, sent back out to uncover more and exciting things about our universe. We've had a great flight so far and everything today has gone just exceedingly well." Preston Burch, Hubble program manager at the Goddard Space Flight Center in Greenbelt, Md., agreed, saying "we're off to a really great start for this mission." "It's always a very exciting time for us on the ground to see Hubble come into view from out in the distance as we approach it, to see the increasing level of detail that comes into view," he said at a morning status briefing. "Of course, we're always very interested to know how it's fared over the past few years since it was serviced the last time. And I can say right now Hubble is in excellent shape." While a detailed photo survey is not yet complete, "our initial examination of the exterior of the observatory does not indicate any significant or noticeable changes since December 1999 when it was serviced last," Burch said. "The solar array retraction procedure today went extremely smoothly and all the other systems are go, the space support equipment that is located in the payload bay of Columbia has all been thoroughly checked out and is working just as you'd expect it to," he added. "So right now, HST is go for EVA day one, tomorrow, and they will be (replacing) the first of the solar array wings. We're looking forward to accomplishing all of our objectives on this mission. We're very pleased so far." The mission's first spacewalk is scheduled to begin at 1:27 a.m. But lead flight director Bryan Austin said astronauts John Grunsfeld and Richard Linnehan probably will begin the excursion early, possibly up to an hour ahead of schedule, to get a leg up on a busy day in space. The astronauts are scheduled to go to bed today at 12:52 p.m. Wakeup is expected at 8:52 p.m. =================================================================== First solar array successfully installed (03/04/02) 12:00 a.m., 03/04/02, Update: Astronauts set for first spacewalk Astronauts John Grunsfeld and Richard Linnehan are gearing up to begin the first of five back-to-back spacewalks to overhaul and upgrade the Hubble Space Telescope. Wearing a spacesuit with red stripes for easy identification, Grunsfeld and Linnehan, wearing a suit with no stripes, are scheduled to float out of the shuttle Columbia's airlock around 1:27 a.m. Monday. The excursion is expected to last about six-and-a-half hours. The goal of the spacewalk is to install the first of two new solar arrays on the space telescope and a diode box assembly to ensure power from the arrays flows toward Hubble's six batteries and not vice versa. The astronauts also will set up tools and equipment needed for all five spacewalks. For the statistically minded, this will be the 14th spacewalk in four Hubble Space Telescope servicing missions. Going into today's outing, 12 astronauts in 13 spacewalks have logged 186 hours and 30 minutes upgrading and overhauling NASA's premier scientific satellite. A convenient chart listing the details of previous Hubble servicing spacewalks will be updated throughout Columbia's mission. "The first EVA day, I think, will set the stage for all five of our space walks," Grunsfeld said in a NASA interview. "First of all, I'll come out of the airlock. And then, Rick Linnehan will come out of the airlock. And for me that's very exciting; he's a classmate of mine. This is his third flight but his first space walk. And so, I'll get to see my friend and my space walking buddy come out of the airlock for the first time on his first space walk. "But, we won't have much time to enjoy the view because this is a very busy day," Grunsfeld said. "This is the day where we have to set up the payload bay. We've gotten to orbit, we've grappled Hubble, put it on the servicing structure, and now we have to go and get the payload bay and Hubble ready for servicing. And that involves a number of activities with putting a special support post under the telescope to rigidize it (the BAPS post). "I'm going to put an antenna cover over a small, delicate antenna at the bottom of the telescope so that we don't inadvertently hit it. Rick is going to be setting up the shuttle robotic arm with a special foot-plate that we can stand on and that holds our tools. So we'll both be very busy right from the start. That'll take about an hour or so. From there, we move straight into the solar array change-out." As viewed from Columbia's aft flight deck, Hubble's two solar arrays will appear face on to the left and right of the telescope's tube, which will extend straight out of the cargo bay. By convention, the left-side array, as viewed from the flight deck, is on the telescope's minus V2 axis while the right-side array is on the positive V2 axis. The arrays were installed during the first Hubble servicing mission in 1993. They weigh 339 pounds each and measure 40 feet long by 10.8 feet wide, delivering about 4,600 watts of power from silicon solar cells. Because of the wear and tear of temperature extremes and normal space radiation, the flexible panels now provide just 63 percent of their original power. In addition, they suffer from structural problems and some shorted circuitry in the wiring connecting all the solar cells. The two new arrays carried aloft aboard Columbia are heavier - 640 pounds per wing - and more powerful, generating some 5,270 watts. While heavier, they are smaller than Hubble's flexible panels, measuring just 23 feet long and 8.5 feet wide. The additional power generated by the new gallium arsenide solar cells will enable astronomers for the first time to operate all of Hubble's instruments at the same time for simultaneous multi-disciplinary observations. In addition, their smaller size will reduce the atmospheric drag that constantly acts to reduce Hubble's altitude. Hubble's old arrays were rolled up Sunday, a few hours after Hubble was captured and mounted on its servicing platform at the rear of the cargo bay. But they are still in place and must be removed before the new arrays can be installed. Once the cargo bay tools are set up, Linnehan will anchor his feet in a foot restraint on the end of the robot arm. Grunsfeld is the designated "free floater" for the first part of the spacewalk. "We'll go up on the telescope about halfway up and we'll take off those flexible arrays that are now rolled up, we'll take them off and put them into the payload bay on the shuttle," Grunsfeld said. "And then, we'll take out the new solar arrays. They're quite a bit different than the old ones. Instead of being rolled up, they're actually rigid arrays and they open like a book. "So, we're going to take these roughly 9-foot-by-12-foot arrays out and Rick is going to hold on to the array and Nancy Currie will lift Rick up out of the payload bay, using the robotic arm, with a 640-pound solar array in front of him. Rick is then going to steer it around towards the telescope, and then together Rick and I will insert it into the fitting onto Hubble. And then Rick is going to open up the solar array, like a book, exposing it to sunlight. "We'll cinch that down, clean up a little bit of the payload bay, and come back in," Grunsfeld said. "There are a few other little things that we're going to do. We're going to wrap some cables in preparation for the next EVA day where we'll put the second solar array on. And then, it's Jim Newman and Mike Massimino's turn to essentially do the same thing on the other side of the telescope." Here is a detailed timeline of today's spacewalk as uplinked to the crew in their morning Execute Package (in EST and mission elapsed time): EST........DD...HH...MM...EVENT 03/03/02 08:52 PM...02...14...30...Crew wakeup 09:02 PM...02...14...40...HST: PGSC checkout 10:37 PM...02...16...15...Medical conference with Grunsfeld and Linnehan 10:52 PM...02...16...30...EVA-1: Preparations begin 03/04/02 12:22 AM...02...18...00...Spacesuit purge and pre-breathe 12:37 AM...02...18...15...Robot arm (RMS) moves to airlock 12:52 AM...02...18...30...RMS ready for EVA support 01:12 AM...02...18...50...EVA-1: Airlock depressurization 01:27 AM...02...19...05...EVA-1: Airlock egress; spacewalk begins 01:37 AM...02...19...15...EVA-1: Initial EVA setup ..........................EV1: Translation aid setup; MFR setup; ..........................low-gain antenna cover installation; BAPS ..........................EV2: MFR ingress at airlock 02:32 AM...02...20...10...EVA-1: -V2 solar array and diode box install ..........................EV1: SA-2 boom retraction; diode box demate; ..........................WFPC cover removal; SA-2 removal from HST; ..........................diode box changeout; SA-3 installation and ..........................closeout; SA-3 panel deploy ..........................EV2: SA-2 prep; WFPC cover retrieval from EV1; ..........................SA-2 removal and temp stow; diode box ..........................retrieval; SA-3 removal from carrier; rotate ..........................and position SA-3 for installation; assist in ..........................attachment and panel deploy 08:02 AM...02...25...40...Grunsfeld and Linnehan trade places on the arm ..........................EV1: P601 connector mate; bay 10 thermal cover ..........................installation ..........................EV2: Install portable foot restraint for ..........................second SA installation 07:07 AM...03...00...45...EVA-1: Daily closeout work 07:37 AM...03...01...15...EVA-1: Airlock ingress 07:47 AM...03...01...25...HST: Solar array slew 07:52 AM...03...01...30...EVA-1: Airlock repressurization 07:52 AM...03...01...30...RMS park 08:07 AM...03...01...45...HST: Solar array functional test 09:22 AM...03...03...00...EVA-2 tools configured 10:02 AM...03...03...40...HST: Solar arrays slewed to 0 degrees 10:37 AM...03...04...15...EVA review 12:52 PM...03...06...30...Crew sleep begins 07:52 PM...03...13...30...HST: Battery discharging 01:40 a.m., 03/04/02, Update: Spacewalk begins Astronauts John Grunsfeld and Richard Linnehan, floating in the shuttle Columbia's airlock, switched their spacesuits to internal battery power at 1:37 a.m., officially beginning a planned six-and-a-half hour spacewalk. This is the 14th spacewalk in four missions devoted to Hubble Space Telescope servicing. Going into today's excursion, 12 astronauts had logged 186 hours and 30 minutes of spacewalk time servicing the $2 billion observatory. 02:25 a.m., 03/04/02, Update: Predicted television downlink windows John Grunsfeld and Richard Linnehan, 45 minutes into a planned six-and-a-half-hour spacewalk, are breaking out tools and equipment needed to replace one of the Hubble Space Telescope's solar arrays. "Hello Mr. Hubble, the telescope!" Grunsfeld called after floating into the shuttle Columbia's cargo bay. "We're here to give you more power to see the planets, stars and the universe." Here are the predicted KU-band television downlink windows for the rest of the day. During these windows, live television from the shuttle is possible, though not guaranteed (times in EST):