Live At KSC: Shuttle Valve Testing Is Under Way

NASA engineers are performing a series of tests on shuttle Discovery's suspect main propulsion system valve and initial reports are promising.

The valve opened and closed as intended when commanded to do so in the first of five tests that began at 6:28 p.m. A pressure decay test of an associated manifold also will be conducted.

Assuming all goes well, NASA engineers would pick up the countdown to a planned 12:22 a.m. Friday launch at 8:57 a.m. Thursday with the clock at T-Minus 11 hours. Engineers then would brief the Mission Management Team on the test results at noon, and a decision on whether to proceed with a launch attempt early Friday would be made at that time.

Here's a list with the timing for major milestones:

++9:57 a.m.: Clear Launch Pad.

++10:47 a.m.: Fuel cell activation.

++Noon: Mission Management Team L-0 meeting.

++12:12 p.m.: Clear "Launch Danger Area".

++1:30 p.m.: Crew wake up.

++1:57 p.m.: Countdown enters 1-hr hold at the T-6 hour mark.

++2:00 p.m.: Crew breakfast.

++2:15 p.m.: Mission Management Team meets to give go for tanking.

++2:30 p.m.: Crew final medical checks.

++2:45 p.m.: NASA TV/External Tank fueling coverage.

++2:57 p.m.: Countdown resumes at T-6 hr mark with External Tank loading.

++3:42 p.m.: Liquid Hydrogen Low Level Cutoff (LLCO) sensors go "wet."

++3:57 p.m.: Liquid Hydrogen "fast fill" begins.

++5:12 p.m.: LH2 "topping" begins (gaseous Hydrogen vent valve cycling).

++5:57 p.m.: Countdown enters 2.5-hr hold (T-3 hr mark). ET in stable replenish. Closeout Crew to White Room. Final Inspection Team (FIT) "walkdown."

++6:30 p.m.: Ascent Team on console in Mission Control in Houston.

++6:30 p.m.: Crew photo opportunity (taped for possible playback later).

++LAUNCH COVERAGE BEGINS on NASA TV. Watch Live In The Flame Trench.

++7:52 p.m.: Crew receives weather brief from Ascent Team.

++Crew suits up for launch.

++8:27 p.m.: Countdown resumes at the T-3 hour mark.

++8:32 p.m.: Crew departs Operations & Checkout Building for Launch Pad 39A.

++Mission Management Team on console in the Launch Control Center at KSC.

++9:02 p.m.: Crew begins to board Discovery.

++9:22 p.m.: T-38 weather reconnaissance (Chief Astronaut Steve Lindsey).

++10:17 p.m.: Discovery's hatch is closed and latched for launch.

++10:37 p.m.: Shuttle Training Aircraft weather reconnaissance (Lindsey).

++10:47 p.m.: White Room Closeout.

++11:07 p.m.: Countdown enters a 10-min hold at the T-20 minute mark.

++11:17 p.m.: Countdown resumes at the T-20 minute mark.

++11:28 p.m.: Countdown enters 45-minute hold at the T-9 minute mark. MMT conducts final "Go/No-Go" poll for launch.

++12:13 a.m.: Countdown resumes at the T-9 minute mark.

++12:22 a.m.: Launch.