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Astronauts prepare for final spacewalk BY WILLIAM HARWOOD STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION Posted: September 15, 2006 Astronauts Joe Tanner and Heidemarie Stefanyshyn-Piper are gearing up for a final spacewalk today to close out work on a new solar array truss and upgrade the international space station's communications system. An airlock circuit breaker tripped early today, but engineers did not see any signs of a short and the device was reset without incident.
Tanner and Piper also will upgrade the space station's S-band communications system, install a thermal blanket around electronics used by the station's high-speed KU-band antenna and retrieve a space exposure experiment. Finally, they will install a wireless antenna system to collect structural data on the solar array truss and clear a safety tether that ended up draped over the path of the station's mobile transporter after a spacewalk Wednesday. The mobile transporter is a high-tech cart that creeps along rails along the front side of the solar array truss. It can lock itself down at various work sites to provide a stable work platform for the Canadarm 2 space crane. Later today, flight controllers will send commands to move the transporter from work site 7 to a new work site - WS-8 - on P3 that will be needed in December to attach another truss segment. Today's spacewalk will be the 72nd devoted to space station assembly and maintenance and the third for the Atlantis astronauts. Tanner and Piper spent six hours and 26 minutes outside Tuesday, wiring in the new P3/P4 truss segments while Dan Burbank and Steve MacLean staged a seven-hour 11-minute spacewalk Wednesday preparing a large solar array drive mechanism for operation. Those two EVAs pushed total spacewalk time on the space station to 431 hours and 54 minutes since assembly began in 1998. As with the previous two spacewalks, Tanner and Piper spent the night inside the Quest airlock module at a reduced pressure of 10.2 pounds per square inch to help purge nitrogen from their bloodstreams, part of a procedure to ensure they don't suffer the bends working in their 5-psi spacesuits. Early today, a remote power controller, or RPC, tripped off, taking down power to the airlock module and its depressurization pump, but engineers later determined there had not been a short and decided to reset the device. "We reset the RPC, we watched the data for a while and then we turned the depress pump back on and it seems to be running just fine now," astronaut Kevin Ford in mission control. "OK. And this is one of those known conditions, characteristics of RPCs?" asked station astronaut Jeff Williams. "We don't think it was a nominal kind of thing, Jeff, we did see a little spike in the current of the depress pump," Ford said. "But it definitely did not look like a short." The RPC troubleshooting put spacewalk preparations about 45 minutes behind schedule. Tanner's call sign is EV-1 and for identification, his spacesuit features solid red stripes around the legs. Piper is EV-2 and her suit has no markings. Here is an updated timeline of today's activity (NOTE: the NASA TV schedule is not yet in synch with the revised spacewalk timeline; in EDT and mission elapsed time):
TIME/EDT DD HH MM EVENT _____________________________________________ 12:15 AM 05 13 00 STS/ISS crew wakeup 12:45 AM 05 13 30 EVA-3: Hygiene break/pre-breathe 01:00 AM 05 13 45 EVA-3: Crew lock repress 01:30 AM 05 14 15 EVA-3: Crew lock depress to 10.2 psi 02:05 AM 05 14 50 EVA-3: Campout EVA prep 03:35 AM 05 16 20 EVA-3: Spacesuit purge 03:50 AM 05 16 35 EVA-3: Spacesuit oxygen pre-breathe 04:40 AM 05 17 25 EVA-3: Crew lock depressurization 05:15 AM 05 18 00 ISS: ISS-13 departure preparation 05:15 AM 05 18 00 EVA-3: Airlock egress/setup; spacewalk begins* 05:30 AM 05 18 15 EVA-3: EV1: P6 BGA latch clips install 05:30 AM 05 18 15 EVA-3: EV2: MISSE 5 experiment retrieval 06:00 AM 05 18 45 EVA-3: EV2: P4 radiator prep and deploy 06:25 AM 05 19 10 EVA-3: EV1: P4 radiator prep and deploy 06:50 AM 05 19 35 EVA-3: P3 cleanup (foot restraints moved) 07:20 AM 05 20 05 EVA-3: S-band antenna support assembly R&R 09:10 AM 05 21 55 EVA-3: EV2: S-band signal processor and transponder R&R 09:20 AM 05 22 05 EVA-3: EV1: KU heat shield installation 09:40 AM 05 22 25 EVA-3: EV1: EWIS antenna installation 10:10 AM 05 22 55 EVA-3: EV2: EWIS antenna installation 10:30 AM 05 23 15 EVA-3: EV1: Infrared camera DTO 11:15 AM 06 00 00 EVA-3: Cleanup 11:35 AM 06 00 20 EVA-3: Airlock repressurization 11:50 AM 06 00 35 Post-EVA spacesuit servicing 12:50 PM 06 01 35 Transporter move from WS-7 to WS-8 01:45 PM 06 02 30 BSA init 02:00 PM 06 02 45 Mission status briefing on NASA TV 02:20 PM 06 03 05 WS-8 checkout 02:35 PM 06 03 20 Transporter move from WS-8 to WS-4 on S0 03:00 PM 06 03 45 Video file on NASA TV 03:45 PM 06 04 30 ISS crew sleep begins 04:15 PM 06 05 00 STS crew sleep begin 05:00 PM 06 05 45 Daily video highlights reel on NASA TV *May be impacted by RPC troubleshooting"EVA 3 is a cleanup of P3 primarily, to prepare it for future missions," Tanner said in a NASA interview. "On P4 we have two activities. One to prepare the radiator for deploy, and then loosen some bolts on an MMOD (micrometeoroid orbital debris) cover. That's kind of a get-ahead, but we'll probably do that as well, and then relocate some foot restraints for (the next assembly crew)." Tanner also will test an infrared camera under development as a diagnostic tool that could help future crews spot damage to the shuttle's wing leading edge panels. It may also prove useful for space station inspections. "If everything that we have planned right now ends up on the plate for EVA 3, it'll take two-and-a-half or three hours probably, of activity (on the new truss)," Tanner said. "Then we say goodbye to P3/P4 and bring all of our tools back in and our tethers and start to work on changing out some things on S1, some tool boxes and the S-band transponder and a signal processor in the S-band communication system." "Heide will be working on an electronic instrumentation antenna on the lab and I'll be heading up to the top of P6 to take care of some unfinished business up there from STS-97, on one balky latch up there, and then putting some clips on some bolts and finally bringing down a science experiment known as MISSE-5. I'll be up on the top for 45 minutes or so and Heide and I will really be separated. And then we join back up again and finish up probably a six, six-and--a-half hour EVA and then head back in."
Burbank and MacLean completed some of the tasks originally planned for today during their spacewalk Wednesday, including removal of no-longer-needed hardware to clear the mobile transporter's path from work site 7 to the new work site 8 on the far left end of the solar array truss.
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STS-115 patch The official crew patch for the STS-115 mission of space shuttle Atlantis to resume orbital construction of the International Space Station. Choose your store:U.S. - U.K. - E.U. - Worldwide  |
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VIDEO:
FIRST SOLAR WING DEPLOYED HALF-WAY 