Space shuttle question
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Dr Jekyll

Original Poster:

23,820 posts

285 months

Tuesday 25th August 2020
quotequote all
Reading Mike Mullane's book excellent book 'Riding rockets' he refers to the call 'Go at throttle up' which refers to the Shuttle engines being set to full power. He says specifically that this call was made immediately before Challenger disintegrated.

Whenever I watched film of a launch, and certainly when I've seen the film of the Challenger disaster, it sounds like 'Go with throttle up', not at.

Am I mishearing? Or is it officially 'at' but people say 'with', like pilots saying 'finals' instead of 'final'?

Eric Mc

124,901 posts

289 months

Tuesday 25th August 2020
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I've always heard it as "Go AT Throttle Up" - but that may be because that was what was normally said and I was predisposed to hearing it.

The "Throttle Up" moment was completely automatic and not something manually operated by the crew or remotely from the ground.

The Solid Rocket Boosters (SRB), which provided most of the thrust at that phase in the flight, were not throttleable. However, the solid fuel was shaped in such a way that the thrust dropped off for the few moments leading up to Max Q (maximum dynamic pressure) and then built back up again to full thrust as soon as Max Q was passed.

The ""Go at throttle up" call was just an affirmation that all the telemetry visible to the flight controllers on the ground were within the expected parameters. The Challenger accident illustrated that the telemetry did not reveal all of the possible flight critical indicators - such as a leaking SRB.