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Columbia’s Engine Shutdown: A Successful Failure With AM-Space Shuttle, Bjt

March 22, 1993

CAPE CANAVERAL, Fla. (AP) _ Monday’s aborted space shuttle launch was an example of a successful failure.

Columbia’s on-board computers did exactly what they were supposed to do when something is wrong with the main engines - halt everything.

″What did work and worked very well, was the safety system,″ launch director Bob Sieck said.

Here’s what did and didn’t work, and why:

When Columbia’s countdown reached 31 seconds, computers on board the ship took over from computers on the ground.

At 6.8 seconds before the scheduled launch, main engine No. 3 was commanded to start, followed by engine No. 2 one-hundred-milliseconds later and No. 1 one-hundred-milliseconds after that.

Engine No. 3 burned for 1.5 seconds, but never came close to reaching full thrust because of a valve that apparently didn’t close.

The two other engines ignited properly.

Meanwhile, Columbia’s computers were performing about 200 tests and repeating them every 20 milliseconds to make sure all systems were ‘go.’

The computers immediately caught the problem and automatically shut the engines down in this order: 3, 2, 1. The last engine shut down at the three- second mark; the countdown clocks stopped.

Inside Columbia, commander Steven Nagel saw the red lights on the control panel and knew the flight had been aborted.

At the launch control center, the letters ″FID″ and numbers flashed on computer screens. ″FID″ stands for failure indication.

″We have seen it many times in practice. The hardware did what it was supposed to do and we are thankful for that,″ said Ron Liston, a NASA launch engineer.

Just in case, if the on-board computers hadn’t ordered the engine shutdown ground computers would have.