Is this what you're looking for?9:41 pm Countdown resumes at the T-3 hour mark12:21 am Countdown enters a 10-minute hold at the T-20 minute mark12:31 am Countdown resumes at the T-20 minute mark12:42 am Countdown enters an ~45-min. hold at the T-9 minute mark1:27:05 am Countdown resumes at the T-9 minute mark
Quote from: wizard on 08/25/2009 01:24 amIs this what you're looking for?9:41 pm Countdown resumes at the T-3 hour mark12:21 am Countdown enters a 10-minute hold at the T-20 minute mark12:31 am Countdown resumes at the T-20 minute mark12:42 am Countdown enters an ~45-min. hold at the T-9 minute mark1:27:05 am Countdown resumes at the T-9 minute markYes, thank you. 10 minute hold at T minus 20, 45 minutes at T-9. How about the T minus 3 hour hold? How long is it?Danny
During tanking/replenish is the LO2 pumped through the SSMEs and then into the tank or is it sent straight up into the tank with a "trickle" sent through the engines, if its option 2 what percentage of the total flow is sent to the engines?
then there should be alternative methods of monitoring the valve position.
What does the scrub scenario look like if one of the LH2 fill/drain valves were to get stuck in the closed position? Wait a week for boiloff via flarestack?
I notice on another thread that after boiloff they have inerted the tank with helium. Is there a reason for using helium for this rather than (say) nitrogen? Is it a concern that the tank is too cold for nitrogen?
Is it due to the volatility of the liquid hydrogen? Or would it waste too much fuel via boil-off?
Quote from: ceepdublu on 08/26/2009 03:45 amWhat does the scrub scenario look like if one of the LH2 fill/drain valves were to get stuck in the closed position? Wait a week for boiloff via flarestack?There's an 8-1/2 minute rapid-drain procedure - but it's likely a one-shot deal
LH2 and LOX are loaded through the T0 umbilicals into the aft of the Orbiter, then up through the porpellant lines and into the respective tanks of the ET.
Quote from: ChrisGebhardt on 08/25/2009 08:08 pmLH2 and LOX are loaded through the T0 umbilicals into the aft of the Orbiter, then up through the porpellant lines and into the respective tanks of the ET.Are the T0 umbilicals those grey things that stand up from the MLP behind the wings?If not, where are they located?
Quote from: joncz on 08/26/2009 03:00 pmQuote from: ceepdublu on 08/26/2009 03:45 amWhat does the scrub scenario look like if one of the LH2 fill/drain valves were to get stuck in the closed position? Wait a week for boiloff via flarestack?There's an 8-1/2 minute rapid-drain procedure - but it's likely a one-shot deal This "8-1/2 minute rapid drain sounds like a "launch" without lighting the SRB's. But, that is not even a consideration right? Wouldn't that require replacement of the SSME's?