April 10 Computers Go To Space

Last Update: Apr 10, 2021

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On this day in 1981, four IBM AP-101 main computers and one backup planned to take a maiden voyage with the Columbia space shuttle, STS-1. In fact they did more than go for the ride, they controlled the flight.

On launch date, those computers were put to the test and failed. Actually they were lucky they could recover so gracefully. Liftoff didn’t even occur on the 10th because some studious NASA engineers discovered a glitch in the shuttle’s computer systems. Synchronization between the main and backup AP-101 flight control computers was out-of-sync.

What Happens When A Mission Faces Problems

Like any great mission, problems did not mean cancelation or abandonment. It just means investigation and fixing. The necessary repairs were made in two days and countdown and launch proceeded with no further setbacks on April 12 from NASA's Kennedy Space Center in Florida.

Success Achieved

The Columbia space shuttle orbited the Earth 34 times before landing safely at Edwards Air Force Base in the Mojave Desert. It was an amazing site because the launch was like a rocket and the landing was like a plane.

So Why Was The AP101 The Chosen Computer?

The instruction set of the AP-101 used the basic instruction set architecture from IBM's mainframe System/360 and was capable of processing 480,000 instructions per second.

In fact it performed its functions so well that it was also used in US military aircraft, including the B-52 and B-1 bombers and the F-15 fighter.

Four computers were used so they could cross-check each other more than 500 times a second. In flight, these digital computers generated electrical signals which controlled the Shuttle orbiter. It is hard to comprehend the power and control a computer offers.

The Computers Were Manned

The April 12, 1981 mission had a two person crew: the commander, John Young, a veteran of Gemini and Apollo, and the pilot, Bob Crippen.

The Mission Objective Was More Than April 10, 1981

The objective of the mission was to make sure that Columbia worked well in space. Since it did this was not the last mission Columbia would make. But we all know its fateful end on February 1, 2003 when it disintegrated as it reentered the atmosphere, killing all seven crew members.


Reading of the tenacity of those involved in this project, it is very evident they were on a mission and were determined to achieve. Their determination to explore and achieve goals is very inspirational.

May this blog reporting of history from the past inspire you to reach new heights today as you continue with your online business mission.

Recent Comments


Very good

Glad you liked it.

Awesome, mission accomplished. NASA has come a long way with its incredible ambition!

Yes. NASA had come a long, long way. That would certainly bring challenges every day.

Thank you and great sharing as always.
Best wishes,

You are welcom.


I've always loved to read and watch historical events such as this one. Nice piece, George. Thanks for sharing.

Glad you enjoyed. I am a history buff too.

Thank you for this inspiring and educational post! Best regards, Rupert.

You are very welcome. Glad you enjoyed it.

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