Close. Very, Very Close
1.9 Seconds To Blast-Off
Every so often NASA has to pull the plug at the last second. Literally. Nancy Atkinson:
Holy Moly! Not to wish anything like this for Saturday’s launch, but I came across this video of the STS-68 launch attempt in 1994 that was aborted at the very last second. Watching it is enough to make your heart stop. Everyone involved must have experienced a tremendous rush followed by extreme let-down! The main engines had lit, but were shut down 1.9 seconds before liftoff when on-board computers detected higher than acceptable readings in a sensor monitoring the discharge temperature of the high pressure oxidizer turbopump in main engine #3. In the history of the shuttle program, five launch attempts were aborted under five seconds from the planned launch. STS-68 came the closest to hauling the mail before being aborted.
Amazing video. NASA points to the “Hydrogen venting system” as the cause of the shutdown.