Back to newsletter listDate:
Mon, March 17, 2008 03:25:37 PMFrom:
CBS Space News
Subject:
220p 3/17 Update: Astronauts prepare for third spacewalk
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CBS NEWS STS-123 STATUS REPORT: 39
Posted: 3:15 PM, 3/17/08
By William Harwood
CBS News Space Analyst
Changes and additions:
SR-36 (03/16/08): Spacewalk No. 2 ends
SR-37 (03/16/08): Crew awakened; Dextre tests on tap
SR-38 (03/16/08): Dextre checked out
SR-39 (03/17/08): Astronauts gear up for third spacewalk
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3:15 PM, 3/17/08, Update: Astronauts gear up for third spacewalk
Astronauts Richard Linnehan and Robert Behnken are gearing up for a planned six-and-a-half-hour spacewalk this evening to complete assembly of a Canadian maintenance robot and to move spare parts and an experiment package from the shuttle Endeavour to the international space station.
The spacewalk is scheduled to begin at 7:23 p.m. when the astronauts, floating in the station's Quest airlock module, switch their spacesuits to battery power. This will be the 107th EVA devoted to station assembly and maintenance since construction began in 1998, the eighth so far this year and the third of five planned for Endeavour's crew.
The astronauts were awakened at 2:30 p.m. today to begin their seventh day in space by a recording of a tune by shuttle pilot Gregory Johnson's brother that was beamed up from mission control.
"Good morning, Endeavour," astronaut Al Drew called from Houston. "And top of the morning to you, Box."
"Good morning, that was my brother singing his original music, 'Sharing the World.' What a way to wake up. We're looking for a really exciting day, spacewalk number three."
Linnehan and Behnken spent the night in the Quest airlock module at a reduced air pressure to help purge nitrogen from their bloodstreams in preparation for today's excursion. This will be Linnehan's third and final spacewalk for this mission while Behnken, making his first, will participate in two more EVAs Thursday and Saturday.
With Linnehan once again on the end of the station's robot arm, the astronauts will wrap up assembly of the Canadian Space Agency's special purpose dexterous manipulator (SPDM) robot, known as Dextre, by removing thermal covers and installing the robot's tool carrier. Behnken also will install a camera pan and tilt unit and prepare the Spacelab pallet that carried Dextre's components into orbit for its eventual reberthing in the shuttle for the return to Earth.
Dextre was launched disassembled. During the crew's first spacewalk last week, gripper-like hands were attached to each of the robot's 11-foot-long arms. The aseembled arms then were attached to Dextre's torso during a spacewalk overnight Saturday.
Each arm features seven joints and all 14 were checked out Sunday. One joint did not meet initial expectations, but station Flight Director Ginger Kerrick said today that all 14 joints had been given a clean bill of health.
"I wouldn't categorize what we saw as a problem," she said. "We performed two separate subtests on the brakes. In the signatures we got back, a few of the joints did not meet the criteria that were specified in the procedure. We had the SPDM engineers on line, following along, they took a detailed look at the signatures we were seeing and they also went back and looked at how they came up with the criteria that was defined in the procedures. They determined that their criteria were a little bit overly conservative and after looking at the data again, they determined that all joints did pass. So there's no impact."
With Dextre's assembly complete, Linnehan will move back to the shuttle's cargo bay, collect an experiment mounting platform and attach it to the outboard end of the European Columbus research module. He then will move a spare robot arm yaw joint and two spare electronic boxes, called direct current switching units, or DCSUs, from the shuttle to an external storage platform on the station.
At that point, Linnehan will be done. As he is winding up his work, Behnken will retrieve a materials exposure experiment, known as MISSE-6, and attach it to the mounting fixture Linnehan earlier bolted to the Columbus module. After the astronauts return to the Quest airlock module, the station's robot arm will lock onto Dextre and remove it from the Spacelab pallet. If all goes well, the robot will be mounted on the Destiny laboratory module Tuesday.
"At the end of today's spacewaklk, the crew members will ... move the SPDM to its overnight position," Kerrick said. "While it's in its overnight position, our robotics officers on the ground will be performing some additional checkouts to make sure the now free end of the SPDM is ready to support the relocation and grapple of the lab grapple fixture."
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
03/17/08
02:28 PM...06...12...00...Crew wakeup
03:08 PM...06...12...40...EVA-3: 14.7 psi repress/hygiene break
03:53 PM...06...13...25...EVA-3: Airlock depress to 10.2 psi
04:18 PM...06...13...50...EVA-3: Campout EVA preps
05:48 PM...06...15...20...EVA-3: Spacesuit purge
05:58 PM...06...15...30...SSRMS setup
06:03 PM...06...15...35...EVA-3: Spacesuit prebreathe
06:53 PM...06...16...25...EVA-3: Crew lock depressurization
07:23 PM...06...16...55...EVA-3: Spacesuits to battery power
07:28 PM...06...17...00...EVA-3: Airlock egress
07:48 PM...06...17...20...EVA-3: Setup
07:58 PM...06...17...30...EVA-3 (Behnken): OTP/THA remove/install
08:08 PM...06...17...40...EVA-3 (Linnehan): OTP/THA remove/install
09:23 PM...06...18...55...EVA-3 (Behnken): Spacelab pallet cleanup
09:23 PM...06...18...55...EVA-3 (Linnehan): Dextre arm 2 EP blanket removal
09:53 PM...06...19...25...EVA-3 (Linnehan): MISSE-6 mounting transfer
10:23 PM...06...19...55...Japanese module outfitting
10:38 PM...06...20...10...EVA-3 (Behnken): CLPA install (2)
10:53 PM...06...20...25...EVA-3 (Linnehan): Yaw joint transfer to ESP-2
11:18 PM...06...20...50...EVA-3 (Behnken): MISSE experiment relocate/deploy
11:38 PM...06...21...10...EVA-3 (Linnehan): DCSU 1 transfer to ESP-2
03/18/08
12:23 AM...06...21...55...EVA-3 (Linnehan): DCSU 2 transfer to ESP-2
01:08 AM...06...22...40...EVA-3: Cleanup
01:28 AM...06...23...00...Station arm (SSRMS) Dextre grapple maneuver
01:28 AM...06...23...00...EVA-3: Airlock ingress
01:53 AM...06...23...25...EVA-3: Airlock repressurization
02:08 AM...06...23...40...SSRMS grapples Dextre
02:28 AM...07...00...00...Spacesuit servicing
03:23 AM...07...00...55...Dextre release from Spacelab pallet
03:30 AM...07...01...02...Mission status briefing on NASA TV
03:43 AM...07...01...15...Dextre overnight park
05:58 AM...07...03...30...ISS crew sleep begins
06:28 AM...07...04...00...STS crew sleep begins
07:00 AM...07...04...32...Daily video highlights reel on NASA TV
11:30 AM...07...09...02...Flight director update on NASA TV
02:28 PM...07...12...00...Crew wakeup
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Quick-Launch Web Links:
CBS News STS-123 Status Reports:
http://www.cbsnews.com/network/news/space/current.html
CBS News STS-123 Quick-Look Page:
http://www.cbsnews.com/network/news/space/currentglance.html
NASA Shuttle Web: http://spaceflight.nasa.gov/shuttle/index.html
NASA Station Web: http://spaceflight.nasa.gov/station/index.html
Spaceflight Now: http://spaceflightnow.com/index.html
GoogleSatTrack: http://www.lizard-tail.com/isana/tracking/
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