630p 11/28 Update: Heat shield inspection complete; weather iffy for Sunday landing

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CBS NEWS STS-126 STATUS REPORT: 79
Posted: 6:25 PM, 11/28/08

By William Harwood
CBS News Space Analyst

Changes and additions:

   SR-77 (11/28/08): Endeavour undocks from space station
   SR-78 (11/28/08): Final shuttle separation burn delayed to avoid close encounter with Russian satellite debris
   SR-79 (11/28/08): Heat shield inspection complete; delayed rocket firing no problem for Picosat deploy; landing weather iffy for Sunday

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6:25 PM, 11/28/08, Update: Heat shield inspection complete; delayed maneuver no problem for Picosat deploy; landing weather iffy for Sunday

The Endeavour astronauts completed a final inspection of the shuttle's nose cap and wing leading edge panels today after undocking from the international space station. No obvious problems were seen, but it will take engineers a day or so to complete their analysis and give the ship a clean bill of health.

Endeavour undocked from the station at 9:47 a.m. The astronauts delayed a final rocket firing to leave the vicinity after an analysis indicated the "burn" would have resulted in a relatively close encounter - 6.8 miles - between the shuttle and a breadbox-size piece of debris from a Russian Cosmos satellite that broke up earlier this year.

Delaying the rocket firing ensured a wider separation and still preserved the right conditions for the deployment of a small "Picosat" on Saturday designed to test solar cell technology.

"The third burn was going to put us in proximity to some junk from a Cosmos satellite that was launched in June of 2006 and subsequently broke up in orbit in March of this year," said lead flight director Mike Sarafin. "The proximity, if we performed that, was going to put us about 11 kilometers from this junk and it just, per the flight rules, it was the safe course of action not to perform that burn."

The delayed rocket firing will "set up a good distance, a relative height distance between the international space station and Endeavour tomorrow before we deploy the Picosat satellite such that the two can fly in proximity to each other over the coming months."

The 23-second rocket firing was carried out around 6:22 p.m. There were no problems.

The astronauts plan to spend the day Saturday packing up, testing re-entry systems and preparing the shuttle for landing Sunday at the Kennedy Space Center. The crew has two back-to-back landing opportunities on successive orbits, the first at 1:19 p.m. and the second at 2:54 p.m.

The Spaceflight Meteorology Group at the Johnson Space Center is predicting a chance of thundershowers within 30 nautical miles of the shuttle's runway and crosswinds of 16 knots, both violations of NASA's safety rules. A low deck of broken clouds and even higher crosswinds are expected Monday, with near ideal conditions predicted Tuesday.

Sarafin said Endeavour has enough on-board supplies to remain in orbit through Tuesday if necessary. Entry flight director Bryan Lunney will outline his landing strategy during a briefing Saturday afternoon.

For Sarafin, getting to this point represents a major accomplishment given the demanding goals of Endeavour's mission.

Over the course of four spacewalks, the astronauts successfully serviced the station's damaged right-side solar array rotary joint, lubricated the port-side joint as a preventative measure, installed a spare cooling system component, removed a spent nitrogen tank, installed a new external TV camera and prepared the Japanese Kibo module for attachment of an external experiment platform next year.

Inside the station, the astronauts installed and activated a new urine recycling system that ultimately will be connected to a new toilet and galley that will permit NASA to boost the station's crew size from three to six next May. Along with the recycling equipment, the shuttle crew also delivered two sleep stations, a refrigerator/freezer and combustion research equipment.

Sarafin said the new toilet will be hooked up in the next two weeks while the station crew hopes to activate the new refrigerator this weekend.

"I am grateful to be here and be at this point where we have accomplished the mission," Sarafin told reporters today after finishing his final planned shift in mission control. "Clearly, everybody did their part and I'm very happy to be here at this point where now it's just a matter of getting Endeavour home.

"If you want to talk about the mission by the numbers, we rotated the crew, Greg Chamitoff is on his way home, Sandy Magnus is now on board the international space station as part of the Expedition 18 crew. We delivered over 1,400 pounds of water for use on board the international space station ... We successfully completed all four of the EVAs, we transferred over eight tons of equipment and logistics to the international space station and are returning home two tons of equipment.

"We also rotated some spare hardware to the space station, a flex hose rotary coupler (for the cooling system) and are returning a nitrogen tank. ... The regenerative life support equipment was problematic at one point during the mission in terms of getting all that equipment up and running in a timely fashion. But the team knew the problem and knew the hardware and quickly fixed it and I just couldn't be happier at this point."

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Quick-Launch Web Links:

CBS News STS-126 Status Reports:
http://www.cbsnews.com/network/news/space/current.html

CBS News STS-126 Quick-Look Page:
http://www.cbsnews.com/network/news/space/currentglance.html

NASA ISS Expeditions Page:
http://www.nasa.gov/mission_pages/station/expeditions/index.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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