The launch of space shuttle Discovery's final flight was delayed another day so that engineers could troubleshoot a faulty backup controller on one of her three main engines.NASA announced the countdown delay at 5:30 pm EDT today, after a backup computer which controls the activity of engine 3 did not come online during routine power checks.
This reporter announced the delay thirty minutes earlier via Twitter (@SpaceLaunchNews).
Mission Management's chairman Mike Moses stated late on Tuesday that the "main engine controller gave us a funny signature" when the launch team tested the computers.
Engines 1, 2 and 3 each have a primary and secondary computer which controls the engines thrust levels and movement during the ascent.
When the launch team went through the power checks, the backup controller on engine three "did not come on," Moses stated. Engineers then power cycled the circuit breaker on Discovery's flight deck for the computer several times to try to get it to come online.
Ninety minutes "later the controller came on, and it started working. It healed its self in time," Moses added.
Overnight tonight and into Thursday midday, the launch team will continue to trouble shoot why the engine controller's electrical signature gave them a hiccup.
NASA also added that the one day delay gives the launch team a much needed rest, having been on console since Sunday afternoon.
The MMT will meet again on Wednesday at 2PM to determine whether or not to pick up the countdown and go fly on Thursday.
If launch is confirmed for Thursday, the launch team will resume the countdown at the T minus 11 hour mark at 5:30 pm on Wednesday.
Lift-off of Discovery's 39th and final space flight will begin at 3:29:43 pm, as the twin solid rocket boosters ignite.
The weather outlook for Thursday is iffy with Air Force meteorologist Kathy Winters giving an 80% unfavorable forecast leading toward launch time. Clouds and moisture within 30 miles of the launch pad will be of concern mid afternoon.
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