alb@alice.UUCP (Adam L. Buchsbaum) (06/26/84)
At T-7 seconds today, Discovery's computer started the SSME ignition sequence, in which all engines are turned on at 120 milllisecond intervals. Two made it, but the computers detected a fuel valve failure in the Number 1 engine and directed it not to fire; they also commanded the other two to shut down. Thus, the countdown was stopped 4 seconds before the SRB's were to have ignited. The engine with the trouble was taken from Challenger earlier in the month, but the fuel valve was apparently one of Discovery's. No word has been given on what sort of delay to expect. It could be several days or several weeks. The crew has been placed on leave status.
karn@mouton.UUCP (06/27/84)
As I understand it, the number 1 engine never started because it was never given the command to fire. The start sequence is 3, then 2, then 1. After starting engine 2, the onboard computers checked the valve state on engine 3 and found the indication(s) that called for an abort. The engine shutdowns were then commanded before the sequence proceeded to start engine number 1. Phil