Hubble's last fix-it mission is also its riskiest

Discussion in 'OFF-Topic / Misc.' started by syscom3, May 10, 2009.

  1. syscom3

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    The grand telescope's fifth and final repair expedition will involve five spacewalks and extended exposure in a debris-filled region. NASA will take extra precautions to protect the shuttle crew.

    Hubble's last fix-it mission is also its riskiest - Los Angeles Times

    NASA - STS-125: The Final Visit

    By John Johnson Jr.
    May 10, 2009

    After 19 years of service, during which time it has provided the most eye-popping images ever of galaxies, nebulae and, most recently, of a planet orbiting an alien star, the Hubble Space Telescope is suffering the pains of old age. It's unsteady, with only half its gyroscopes working, and several of its key science instruments are broken.

    To restore the ailing telescope to its former glory, NASA on Monday is set to launch the fifth and final repair mission to the orbiting telescope.

    The Hubble mission is unusually risky, even by space travel standards, involving five spacewalks and extended time in the debris-riddled layer above Earth, where even a small collision with space junk could render the shuttle useless. The vulnerability of the shuttle fleet to small bits of flotsam was tragically demonstrated by the destruction of the shuttle Columbia in 2003, which was hit during liftoff by a piece of foam insulation from the external fuel tank. The searing heat of reentry widened the hole on the left wing and destroyed the orbiter as it attempted to land in Florida.

    Top NASA officials say they will do everything they can to ensure the safety of the crew of the shuttle Atlantis, including flying the orbiter upside down and backward to minimize the danger of being struck by space debris and having a second shuttle on the launchpad in case a rescue mission must be mounted.

    "This is going to be an extremely challenging mission," said shuttle pilot Greg Johnson.

    Big Bang quest

    If successful, the mission will leave the telescope with six new gyroscopes, six fully charged batteries, and four repaired or replaced cameras and spectrographs, including the workhorse wide-field camera No. 2 that was responsible for some of Hubble's most dramatic images. The repairs will keep Hubble functioning at peak efficiency at least through 2014, by which time the next-generation James Webb telescope is scheduled to take its place.

    This suite of upgraded instruments will enable the refurbished telescope to look back in time to the very beginnings of the universe.

    "This will be our first realistic chance of detecting the first stars and galaxies that formed" right after the Big Bang, almost 14 billion years ago, said UCLA astronomer Matthew Malkan, whose team will be among the first users of the refurbished instrument.

    Malkan estimates that the reborn Hubble will be 100 times as powerful as it was when it was carried to orbit in April 1990.

    It might even be powerful enough to find the current Holy Grail of cosmology -- the source of the dark matter and dark energy that is thought to make up as much as 96% of the universe. Although neither has been detected directly, scientists believe they must exist to explain the behavior of galaxy clusters and the fact that the expansion of the universe is speeding up.

    "I truly believe that 100 years from now people will still remember Hubble and what it did," said David Leckrone, a senior scientist with the Hubble team.

    The mission is not without controversy. In fact, it was canceled after the Columbia disaster, out of concern that a problem with Atlantis could leave the crew stranded in space. Then-NASA Administrator Sean O'Keefe declared at the time that the only safe destination for the shuttle fleet was the International Space Station, which could offer a haven to the crew of a damaged shuttle.

    It took the intervention of Congress, which earmarked money to NASA with the restriction that it could be used only on a Hubble repair mission, and the appointment of a new administrator, Michael Griffin, to get the mission back on the manifest.

    "I thought this was a mission we ought to be doing," said Griffin, who recently left the agency for a teaching position at the University of Alabama in Huntsville. "For the cost of one shuttle mission, we get a chance to have a brand new telescope in Earth orbit."

    With most of its instruments hobbled or out of service, Hubble today "is like a champion athlete playing hurt," Leckrone said.

    On the to-do list

    NASA's schedule calls for Atlantis to rendezvous with Hubble on the third day of the 12-day mission. Mike Massimino is one of several crew members who has visited Hubble before. As a member of the 2002 mission, he recalls the thrill of catching a glimpse of the big telescope floating languidly in space.

    "As you come up, it looks like a star on the horizon," Massimino said.

    After pulling alongside Hubble, crew member Megan McArthur will operate Atlantis' onboard grappling arm to haul the school-bus-sized, 44-foot-long, 12-ton telescope into the shuttle's payload bay, where it will be attached to a special berthing mount that will allow easy access to all its instruments.

    Day 4 is when the real work begins, with the first of the five spacewalks, each lasting more than six hours.

    The repair team will have at its disposal a kit of 180 tools, 116 developed just for this mission. And 316 bolts will be loosened and refastened as the spacewalkers wrestle the new instruments into position.

    The weightlessness of space will be an ally as the spacewalkers struggle with massive instruments, such as a 900-pound wide-field planetary camera.

    Even so, NASA says the sheer volume of work to be done over a relatively short period of time will make this the toughest, most tightly scheduled repair mission to date.

    The spacewalkers will cut the telescope loose on the ninth day of their mission. Atlantis will then quickly descend to a lower altitude to reduce the risk of being hit by such orbital debris as old rocket parts, lost screwdrivers and castoff nuts and bolts. The region where the telescope orbits is much more congested with debris than the lower altitude, where the International Space Station orbits.

    The danger is that even a small piece of debris traveling at 17,000 miles an hour could puncture the skin of the shuttle, rendering it unusable for the return trip to Earth.

    NASA engineers have calculated that there is a 1-in-221 chance of a catastrophic accident caused by orbital debris that would destroy the shuttle and kill the seven-member crew. Some assessments have put the risk of danger even higher, at 1 in 167. That would violate NASA's margin of safety, which states that a risk higher than 1 in 200 is unacceptable.

    "We've paid close attention to this risk," deputy shuttle program manager LeRoy Cain said in a recent briefing with reporters. "We feel it's acceptable to go fly."

    Flying upside down and backward while the crew works on Hubble is one way of curbing risk. That configuration protects the shuttle's nose cone and its vulnerable wing edges.

    Rescue plan

    If all NASA's efforts to protect Atlantis fail and the orbiter is damaged, either during launch or by orbital debris, the crew will have to be rescued by a second shuttle. That shuttle, Endeavour, will be standing by on a nearby launchpad when Atlantis lifts off. Endeavour could blast off on a rescue mission within a matter of days, officials said.

    Atlantis will carry 25 days' worth of provisions, enough to tide the crew over should it need to wait for Endeavour. In a rescue, the Atlantis crew would be transferred one by one to the rescue orbiter. Then, Atlantis would be destroyed.

    Massimino said he wasn't worried about his safety. NASA has learned a lot since the Columbia accident, he said.

    "If we do have damage, there is a pretty good chance we can go and fix it," he said.

    After Columbia was destroyed, NASA engineers developed repair techniques to plug holes, though none has been tried in a real emergency.

    "If I was too concerned" about the risk, Massimino said in a phone interview from Johnson Space Center in Houston, "I wouldn't be doing it."

    Critics said the willingness of the astronauts to put themselves in harm's way should not be a consideration when deciding whether to permit a mission in space.

    "Just because the astronauts are prepared to have a fancy funeral if something goes wrong, that doesn't mean the taxpayers should have to pay for their blaze of glory," said John Pike, a space policy analyst for GlobalSecurity.org.

    The mission is just as risky now as it was when O'Keefe canceled it, Pike said, adding that the only thing that has changed is the politics.

    Pike's opinion is a minority one. Other observers said they thought NASA had worked hard to minimize risk.

    They also say that changes to the shuttle fleet, such as redesigning the external fuel tank to minimize the amount of insulating foam that falls off during a launch, have made the shuttles safer than they were when Columbia was fatally damaged.

    "Yes, it's risky to fly in space, period. Yes, it's risky to fly in a place with more orbital debris. But I believe these guys have calculated the danger pretty well," said Roger Launius, a space expert and historian at the Smithsonian Institution in Washington.

    "These are not teenagers with a souped-up engine running down the road at 130 miles an hour. The risk is certainly worth it in the context of keeping a world-class scientific instrument operating."

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  2. RabidAlien

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  4. syscom3

    syscom3 Pacific Historian

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    DATE/EDT.......DD...HH...MM...EVENT
    Flight Day 2
    05/12/09

    Tue 09:01 PM...01...07...00...Crew sleep begins
    Tue 09:36 PM...01...07...35...HST: Maneuver to rendezvous attitude
    Tue 10:01 PM...01...08...00...HST: Low-gain direct to TDRS
    Tue 10:26 PM...01...08...25...HST: 3 gyro ops reconfig

    05/13/09
    Wed 03:26 AM...01...13...25...HST: High gain antenna retraction

    Flight Day 3

    Wed 05:01 AM...01...15...00...Crew wakeup
    Wed 07:26 AM...01...17...25...Group B computer powerup
    Wed 07:41 AM...01...17...40...Rendezvous operations timeline begins
    Wed 08:11 AM...01...18...10...Middeck preps
    Wed 08:41 AM...01...18...40...EVA-1; Tools configured
    Wed 08:51 AM...01...18...50...HST: Solar arrays slewed to 90 degrees
    Wed 09:02 AM...01...19...01...NC-4 rendezvous rocket firing
    Wed 10:41 AM...01...20...40...TI rendezvous rocket firing
    Wed 12:01 PM...01...22...00...HST: Move to capture attitude
    Wed 12:54 PM...01...22...53...HST capture
    Wed 01:46 PM...01...23...45...HST berthing
    Wed 02:01 PM...02...00...00...HST survey
    Wed 02:16 PM...02...00...15...External power on
    Wed 02:46 PM...02...00...45...Group B power down
    Wed 03:56 PM...02...01...55...SRMS park
    Wed 04:21 PM...02...02...20...HST: Solar arrays slewed to 0 degrees
    Wed 04:41 PM...02...02...40...EVA-1: Procedures review
    Wed 06:26 PM...02...04...25...HDTV downlink
    Wed 08:31 PM...02...06...30...Crew sleep begins
    Wed 09:21 PM...02...07...20...HST: KU-band checkout
    Wed 09:46 PM...02...07...45...HST: Engineering data playback

    Flight Day 4

    05/14/09
    Thu 03:01 AM...02...13...00...HST: SSR engineering playback
    Thu 04:31 AM...02...14...30...Crew wakeup
    Thu 05:46 AM...02...15...45...EVA-1: Preparations begin
    Thu 07:16 AM...02...17...15...EVA-1: Spacesuit purge
    Thu 07:26 AM...02...17...25...EVA-1: Spacesuit pre-breathe
    Thu 08:06 AM...02...18...05...EVA-1: Airlock depressurization
    Thu 08:16 AM...02...18...15...EVA-1: Spacesuits to battery power
    Thu 08:21 AM...02...18...20...EVA-1: Airlock egress and setup
    Thu 09:21 AM...02...19...20...EVA-1: WFC 3 installation
    Thu 09:21 AM...02...19...20...HST: WFC3 aliveness test
    Thu 11:36 AM...02...21...35...EVA-1: SI C&DH installation
    Thu 12:56 PM...02...22...55...HST: SI C&DH aliveness test
    Thu 01:06 PM...02...23...05...EVA-1: SCM and locks
    Thu 02:01 PM...03...00...00...EVA-1: Cleanup and airlock ingress
    Thu 02:01 PM...03...00...00...HST: SI C&DH functional test
    Thu 02:36 PM...03...00...35...HST: Solar array slewed to 90 degrees
    Thu 02:46 PM...03...00...45...EVA-1: Airlock repressurization
    Thu 02:56 PM...03...00...55...Spacesuit servicing
    Thu 03:36 PM...03...01...35...HST: WFC3 functional test
    Thu 04:01 PM...03...02...00...EVA-2: Tools configured
    Thu 04:01 PM...03...02...00...Spacesuit swap
    Thu 05:01 PM...03...03...00...EVA-2: Procedures review
    Thu 08:31 PM...03...06...30...Crew sleep begins
    Thu 09:46 PM...03...07...45...HST: SSR engineering playback

    05/15/09
    Fri 01:16 AM...03...11...15...HST: SSR engineering playback

    Flight Day 5

    Fri 03:01 AM...03...13...00...HST: Bay 2 battery discharge
    Fri 04:31 AM...03...14...30...Crew wakeup
    Fri 05:46 AM...03...15...45...EVA-2: Preparations begin
    Fri 07:16 AM...03...17...15...EVA-2: Spacesuit purge
    Fri 07:26 AM...03...17...25...EVA-2: Spacesuit pre-breathe
    Fri 08:06 AM...03...18...05...EVA-2: Airlock depressurization
    Fri 08:16 AM...03...18...15...EVA-2: Spacesuits to battery power
    Fri 08:21 AM...03...18...20...EVA-2: Airlock egress and setup
    Fri 09:01 AM...03...19...00...EVA-2: Rate sensing unit replacement
    Fri 12:21 PM...03...22...20...EVA-2: Bay 2 battery pack
    Fri 01:56 PM...03...23...55...EVA-2: Cleanup and airlock ingress
    Fri 02:01 PM...04...00...00...HST: Battery aliveness test
    Fri 02:36 PM...04...00...35...HST: Solar arrays slewed to 90 degrees
    Fri 02:41 PM...04...00...40...EVA-2: Airlock repressurization
    Fri 02:51 PM...04...00...50...Spacesuit servicing
    Fri 03:01 PM...04...01...00...HST: Battery functional test
    Fri 03:56 PM...04...01...55...EVA-3: Tools configured
    Fri 03:56 PM...04...01...55...LIOH and battery config
    Fri 04:16 PM...04...02...15...Spacesuit swap
    Fri 04:51 PM...04...02...50...HST: Solar arrays slewed to 0 degrees
    Fri 05:11 PM...04...03...10...HST: RSU functional test
    Fri 05:21 PM...04...03...20...EVA-3: Procedures review
    Fri 08:31 PM...04...06...30...Crew sleep begins
    Fri 08:41 PM...04...06...40...HST: SSR engineering playback

    Flight Day 6

    05/16/09
    Sat 03:26 AM...04...13...25...HST: SSR engineering playback
    Sat 04:31 AM...04...14...30...Crew wakeup
    Sat 05:46 AM...04...15...45...EVA-3: Preparations begin
    Sat 07:16 AM...04...17...15...EVA-3: Spacesuit purge
    Sat 07:26 AM...04...17...25...EVA-3: Spacesuit pre-breathe
    Sat 08:06 AM...04...18...05...EVA-3: Airlock depressurization
    Sat 08:16 AM...04...18...15...EVA-3: Spacesuits to battery power
    Sat 08:21 AM...04...18...20...EVA-3: Airlock egress and setup
    Sat 08:46 AM...04...18...45...EVA-3: Cosmic Origins Spectrograph
    Sat 10:46 AM...04...20...45...HST: COS aliveness test
    Sat 11:36 AM...04...21...35...EVA-3: ACS repair (part 1)
    Sat 02:01 PM...05...00...00...EVA-3: Cleanup and airlock ingress
    Sat 02:46 PM...05...00...45...EVA-3: Airlock repressurization
    Sat 02:46 PM...05...00...45...HST: COS functional test
    Sat 02:56 PM...05...00...55...Spacesuit servicing
    Sat 04:01 PM...05...02...00...EVA-4: Tools configured
    Sat 04:01 PM...05...02...00...LIOH and battery config
    Sat 04:21 PM...05...02...20...Spacesuit swap
    Sat 05:21 PM...05...03...20...EVA-4: Procedures review
    Sat 08:31 PM...05...06...30...Crew sleep begins
    Sat 09:46 PM...05...07...45...HST: SSR engineering playback

    Flight Day 7

    05/17/09
    Sun 03:31 AM...05...13...30...HST: SSR engineering playback
    Sun 04:31 AM...05...14...30...Crew wakeup
    Sun 05:46 AM...05...15...45...EVA-4: Preparations begin
    Sun 07:16 AM...05...17...15...EVA-4: Spacesuit purge
    Sun 07:26 AM...05...17...25...EVA-4: Spacesuit pre-breathe
    Sun 08:06 AM...05...18...05...EVA-4: Airlock depressurization
    Sun 08:16 AM...05...18...15...EVA-4: Spacesuits to battery power
    Sun 08:21 AM...05...18...20...EVA-4: Airlock egress and setup
    Sun 08:46 AM...05...18...45...EVA-4: STIS repair
    Sun 12:26 PM...05...22...25...HST: STIS aliveness test
    Sun 12:56 PM...05...22...55...HST: STIS functional test
    Sun 01:16 PM...05...23...15...EVA-4: NOBL 8
    Sun 02:01 PM...06...00...00...EVA-4: Cleanup and airlock ingress
    Sun 02:46 PM...06...00...45...EVA-4: Airlock repressurization
    Sun 02:56 PM...06...00...55...Spacesuit servicing
    Sun 04:01 PM...06...02...00...LIOH and battery config
    Sun 04:01 PM...06...02...00...EVA-5: Tool config
    Sun 04:21 PM...06...02...20...Spacesuit swap
    Sun 05:16 PM...06...03...15...EVA-5: Procedures review
    Sun 08:31 PM...06...06...30...Crew sleep begins
    Sun 09:41 PM...06...07...40...HST: SSR engineering playback
    Sun 11:31 PM...06...09...30...HST: Bay 3 battery discharge

    05/18/09
    Mon 03:26 AM...06...13...25...HST: SSR engineering playback

    Flight Day 8

    Mon 04:31 AM...06...14...30...Crew wakeup
    Mon 05:46 AM...06...15...45...EVA-5: Preparations begin
    Mon 07:16 AM...06...17...15...EVA-5: Spacesuit purge
    Mon 07:26 AM...06...17...25...EVA-5: Spacesuit pre-breathe
    Mon 08:06 AM...06...18...05...EVA-5: Airlock depressurization
    Mon 08:16 AM...06...18...15...EVA-5: Spacesuits to battery power
    Mon 08:21 AM...06...18...20...EVA-5: Airlock egress and setup
    Mon 08:46 AM...06...18...45...EVA-5: Bay 3 battery R&R
    Mon 10:06 AM...06...20...05...HST: Battery aliveness test
    Mon 10:16 AM...06...20...15...EVA-5: FGS-2 R&R
    Mon 11:41 AM...06...21...40...HST: FGS-2 aliveness test
    Mon 12:16 PM...06...22...15...EVA-5: NOBL 5
    Mon 12:46 PM...06...22...45...EVA-5: Cleanup and airlock ingress
    Mon 01:46 PM...06...23...45...HST high gain antenna deploy (1)
    Mon 01:56 PM...06...23...55...EVA-5: Airlock repressurization
    Mon 02:11 PM...07...00...10...Spacesuit servicing
    Mon 02:21 PM...07...00...20...HST: Solar arrays slewed to 90 degrees
    Mon 02:41 PM...07...00...40...HST: Battery functional test
    Mon 03:16 PM...07...01...15...LIOH and battery config
    Mon 03:36 PM...07...01...35...Spacesuit swap
    Mon 04:11 PM...07...02...10...HST high gain antenna deploy (2)
    Mon 04:21 PM...07...02...20...Rendezvous tools checkout
    Mon 04:46 PM...07...02...45...HST: FGS-2 functional test
    Mon 08:31 PM...07...06...30...Crew sleep begins
    Mon 09:41 PM...07...07...40...HST: SSR engineering playback

    Flight Day 9

    05/19/09
    Tue 03:26 AM...07...13...25...HST: SSR engineering playback
    Tue 04:31 AM...07...14...30...Crew wakeup
    Tue 06:01 AM...07...16...00...Group B computer powerup
    Tue 06:16 AM...07...16...15...SRMS grapples HST
    Tue 06:56 AM...07...16...55...HST power umbilical disconnect
    Tue 07:06 AM...07...17...05...HST unberthing maneuver
    Tue 07:36 AM...07...17...35...EVA prep
    Tue 07:51 AM...07...17...50...HST release prep
    Tue 08:16 AM...07...18...15...HST: Aperture door open
    Tue 08:53 AM...07...18...52...HST release
    Tue 08:54 AM...07...18...53...Separation burn No. 1
    Tue 09:27 AM...07...19...26...Separation burn No. 2
    Tue 09:51 AM...07...19...50...FSS stow
    Tue 10:11 AM...07...20...10...Crew meals
    Tue 11:02 AM...07...21...01...Orbit adjust rocket firing
    Tue 11:11 AM...07...21...10...Group B computer powerdown
    Tue 11:11 AM...07...21...10...SRMS unberths OBSS
    Tue 12:51 PM...07...22...50...Starboard wing RCC survey
    Tue 02:31 PM...08...00...30...EVA tools stowed
    Tue 02:41 PM...08...00...40...Nose cap survey
    Tue 03:31 PM...08...01...30...Port wing RCC survey
    Tue 04:31 PM...08...02...30...HST: 2nd ARU attitude
    Tue 05:51 PM...08...03...50...OBSS ICC RCC survey
    Tue 06:31 PM...08...04...30...LDRI downlinkn
    Tue 08:31 PM...08...06...30...Crew sleep begins
     
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