Endeavour likely to return to Earth "as is"

NASA mission managers are poised to give Endeavour's astronauts a green light to return to Earth without making repairs to gouged tiles on the underside of the orbiter.

If, that is, final tests in a reentry simulator at Johnson Space Center in Houston continue to show that no significant damage would be done to the shuttle's fragile heat-shield during a fiery plunge back through the atmosphere.

"If there are no surprises in this arc jet test...it is likely the (Mission Management Team) will conlude that the damage is acceptable for reentry without repair,"a message beamed up to the crew today says.

A group of senior managers responsible for shuttle and crew safety during the course of an ongoing flight, the Mission Management Team (MMT) now is scheduled to meet at 4 p.m. today to decide whether spacewalking repairs to the gouged tiles will be necessary. The meeting was pushed back two hours to allow engineers to complete testing and analyses.

The Endeavour astronauts are being kept up to speed via detailed summaries of work taking place on the ground.

A high-level overview can be found in the Flight Day 9 Execute Package beamed up to the astronauts earlier today: FD09_Execute_Package.pdf. Scroll down to Message 89.

A more detailed summary of the ongoing discussion can be found in Message 79, which was sent up separately: msg079.pdf.

The astronauts are preparing as if they will be called upon to do repairs. Ground controllers beamed up this 62-page Tile Repair Overview Package (7MB) for the astronauts to study. It details all the tools and techniques they would use to do the job: msg082.pdf.

Endeavour mission specialists Rick Mastracchio and Dave Williams would team up to perform the repairs. Mastracchio would take the lead because he helped develop repair techniques in a human thermal vacuum chamber at JSC. The preliminary timeline for a spacewalk to repair the gouged tiles is here: msg090.pdf.

The risks involved with spacewalking repairs, however, are non-trivial. The technical report here outlines some of the dangers:

TILE%20REPAIR%20HAZARDS.pdf.

Senior NASA managers will brief the media on their final decision during a news conference now scheduled for 6 p.m. The actual start time is expected to be later in the evening.

You can watch the news briefing -- and NASA TV coverage of ongoing mission operations -- here in The Flame Trench. Simply click the link below the Mission Webcast headline above to launch our NASA TV viewer. Start-up time is about 20 seconds.