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Astronauts set for one last Hubble spacewalk BY WILLIAM HARWOOD STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION Posted: May 18, 2009 Running ahead of schedule, astronauts John Grunsfeld and Andrew Feustel are suiting up for the Atlantis crew's fifth and final spacewalk today, a six-hour excursion to equip the Hubble Space Telescope with a second three-battery power pack, a refurbished fine guidance sensor and fresh equipment bay insulation panels. One panel was deferred from a spacewalk Sunday when the crew ran out of time. Grunsfeld and Feustel plan to install it today if time is available.
In a news conference before launch, asked he he planned to "leave his mark" on Hubble, Grunsfeld said yes, "I think we all plan to leave our mark. And it's Wide Field Camera 3, it's Cosmic Origins Spectrograph, RSUs, batteries, fine guidance sensor." Then he joked that robot arm operator Megan McArthur "hopes to leave no marks at all on the telescope with the arm." But given Grunsfeld's long history with Hubble, his role as NASA's chief scientist when he had to support former Administrator Sean O'Keefe's controversial decision to cancel this final servicing mission and his subsequent assignment to the crew when the flight was reinstated, NASA's most experienced Hubble astronaut almost certainly will have something memorable to say before returning to Atlantis' airlock. Today's spacewalk is scheduled to begin around 9:16 a.m., although the crew was running well ahead of schedule and hoped to get out the door early. For identification, Grunsfeld, call sign EV-1, will be wearing a spacesuit with red stripes around the legs. Feustel, call sign EV-2, will be wearing an unmarked suit. In a reversal of roles from their earlier spacewalks, Grunsfeld will ride the shuttle's robot arm while Feustel will free float. One of the top priorities of Atlantis' servicing mission was to install six fresh nickel-hydrogen batteries to replace a degraded set that has been in place since launch in 1990. The first three-battery power module was installed in equipment bay 2 during the crew's second spacewalk Friday. Today, the final power module will be installed in bay 3. Feustel will prepare the new battery pack for removal from its transport container, removing 12 bolts holding it in place, while Grunsfeld, on the end of the shuttle's robot arm, opens the bay 3 door on Hubble and removes the old batteries, releasing 14 bolts and six electrical cables. McArthur, operating the robot arm, will move Grunsfeld back down to the cargo bay to swap battery packs with Feustel, who will store the old set for return to Earth while Grunsfeld installs the new set on the telescope. The next item on the agenda is installation of a refurbished fine guidance sensor, one of three that provides data to the telescope's computer system to help lock onto and track its astronomical targets. "There are lots of ways that the pointing system on Hubble acquires targets, locks in on those targets, and then allows the science to be produced," Grunsfeld said in a NASA interview. "It has some eyeballs on the outside of the telescope, which are the fixed head star trackers, and they kind of give Hubble that 'Snoopy' look. They acquire the general orientation of the telescope just as the ancient mariners did by looking up at the sky as they were crossing the ocean. "Once you get into the vicinity of where you want to look the fixed head star trackers' job is done and the fine guidance sensors take over. And what they do is they steal a little bit of light from the primary mirror. The light goes up from the primary mirror to the secondary and through a hole in the middle of the primary mirror, and the fine guidance sensors take that light, look at stars, identify them, lock onto them, and that's how the telescope points in the right place in the sky. And then the rate sensor units take care of all the little oscillations and disturbances. All these parts work together." Grunsfeld and Feustel first will remove the old FGS 2, opening an access door, attaching a handling fixture, disconnecting electrical cables and attachment clamps and pulling the 900-pound unit out along its guide rails. The old FGS will be temporarily mounted on an access platform along the left wall of the payload bay. The replacement FGS then will be removed from its transport container and moved to Hubble for installation. After bolting it in place and making the required electrical connections, Grunsfeld and Feustel will retrieve the old FGS and mount it in the transport container for return to Earth. The flight plan originally called for installation of a new outer blanket layer - NOBL - insulation panel on equipment bay 8 Sunday, during the crew's fourth spacewalk, followed by a NOBL panel for bay 5 today. But the NOBL 8 panel was deferred Sunday when work to repair Hubble's Space Telescope Imaging Spectrograph ran longer than expected. The spacewalkers hope to install both NOBLs today, on equipment bays 5 and 8, if time is available. Grunsfeld described the NOBL panels as "big pizza sheets that we're going to put on the outside of the telescope where the insulation has become damaged and is peeling up and the stuff inside is either getting too hot or too cold. So we're going to fix those items." Because this is the crew's fifth spacewalk in a row, flight controllers do not want it to run long because of concern about crew fatigue. Grunsfeld said Sunday, however, that the crew is in good shape and eager to complete the work. Here is an updated timeline of today's activity (in EDT and mission elapsed time; includes revision F of the NASA television schedule): EDT........DD...HH...MM...EVENT 05:31 AM...06...15...30...Crew wakeup 06:46 AM...06...16...45...EVA-5: Preparations begin 08:16 AM...06...18...15...EVA-5: Spacesuit purge 08:26 AM...06...18...25...EVA-5: Spacesuit pre-breathe 09:06 AM...06...19...05...EVA-5: Airlock depressurization 09:16 AM...06...19...15...EVA-5: Spacesuits to battery power 09:21 AM...06...19...20...EVA-5: Airlock egress and setup 09:46 AM...06...19...45...EVA-5: Bay 3 battery R&R 11:06 AM...06...21...05...HST: Battery aliveness test 11:16 AM...06...21...15...EVA-5: FGS-2 replacement 12:41 PM...06...22...40...HST: FGS-2 aliveness test 01:16 PM...06...23...15...EVA-5: NOBL 5 (NOBL8 if time is available) 01:46 PM...06...23...45...EVA-5: Cleanup and airlock ingress 02:46 PM...07...00...45...HST high gain antenna deploy (1) 03:01 PM...07...01...00...EVA-5: Airlock repressurization 03:11 PM...07...00...10...Spacesuit servicing 03:21 PM...07...01...20...HST: Solar arrays slewed to 90 degrees 03:41 PM...07...01...40...HST: Battery functional test 04:00 PM...07...01...59...Mission status briefing on NTV 04:16 PM...07...02...15...LIOH and battery config 04:26 PM...07...02...25...Spacesuit swap 05:11 PM...07...03...10...HST high gain antenna deploy (2) 05:11 PM...07...03...10...Rendezvous tools checkout 05:56 PM...07...03...55...HST: FGS-2 functional test 06:16 PM...07...04...15...HD downlink opportunithy 08:31 PM...07...06...30...Crew sleep begins 08:45 PM...07...06...44...HST update on NTV 09:00 PM...07...06...59...Daily highlights reel on NTV 10:01 PM...07...08...00...HST: SSR engineering playback
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VIDEO:
NARRATED PREVIEW OF SPACEWALK NO. 5 