Apur-ee.161 net.columbia utzoo!decvax!pur-ee!davy Wed Nov 4 10:15:00 1981 Mission Scrubbed Shortly before T -31 seconds before liftoff this morning, Shuttle Control detected a problem with the LOX pressure in the fuel tanks for the APUs (Auxilliary Power Units). The pressure, which should have been 800 lbs./sq.in. (?) was approximately one p.s.i. below the launch criterion. George Page, Launch Director, decided to go ahead with the launch, however, when the attempt was made to switch over to the shuttle's onboard computers, a problem arose which caused the clock to stop at T -31 seconds. It turns out that a "software management problem" with the programs in the onboard computers prohibited the onboard computers from taking over. Basically, what happened is someone didn't write the code to let the computers take over when an "acceptable" discrep- ancy arose (the pressure problem). The clock was re-set to T -9 minutes, and then to T -20 min. At 9:35 EST this morning, the clock was due to begin countdown again, this would have included a built-in 10 minute hold at T -9 minutes. This would have set liftoff time at roughly 10:05 EST. However, at 9:45 EST, the mission was "scrubbed" for today. Another problem discovered, was that the lubrication oil pressure in two of the three APUs was too high. Officials did not know what caused this, but decided to scrub the mission. This means that the earliest takeoff time is at least 48 hours away. The reason for this 48 hour delay is that the fuel tanks must be drained of the cryogenic fuel (LOX) in order to avoid rupturing the insulation. The process of drainiing, temperature conditioning, and reloading the tanks will take 48 hours. This is the EARLIEST time for takeoff, and weather reports indicate that it may be even later. --Dave ----------------------------------------------------------------- gopher://quux.org/ conversion by John Goerzen of http://communication.ucsd.edu/A-News/ This Usenet Oldnews Archive article may be copied and distributed freely, provided: 1. There is no money collected for the text(s) of the articles. 2. The following notice remains appended to each copy: The Usenet Oldnews Archive: Compilation Copyright (C) 1981, 1996 Bruce Jones, Henry Spencer, David Wiseman.