G.A.S. Project

(Flew: September 1992)


While attending the University of Washington I had the privilege of working on a Get-Away Special (GAS). These projects are low-cost experiments regularly flown by NASA on the Shuttle, so that academic and other institutions can gain access to zero-gravity environments without incurring the costs of launching a satellite.

Our GAS Project was conducted to test the collection of fluid in microgravity using a centrifuge. It was the hardware component of a larger device designed for heat dissipation on permanent space fixtures such as a space station. My responsibility was to program the computer that made the experiment work and collect data.

As such, I worked with a Q85 system, authoring in 8085 assembly and burning programs onto EEPROMs before inserting the chips and testing the system. There was no debugger, I hooked up an LED bank to the A/D and videotaped the flashing lights for runs that would last hours at a time. Using this analog debugger was slow and tedious, but I was able to complete the program in time and the experiment flew in September of 1992 on the STS-47.

Here's a link regarding that flight: Space Shuttle Mission Chronology STS-47

Of course, even the best laid plans don't always work out. When we cycled the motor to the lowest RPM in zero gravity it ended up actually stopping the bowl from rotating. This was an unanticipated side effect that we had never seen in our earth-based testing. When the bowl stopped rotating, fluid stopped circulating and the experiment essentially self-destructed. A lovely movie of this is available in the links which follow.

Subsequent to our flight, other students were able to fix this engineering problem and fly the experiment again without the error. By that time I had already moved on, my memories of the GAS Lab relegated to midnight ramblings and old war stories told around the pot-bellied stove.


In-Flight Camera 2 QuickTime Movie

Description: This in-flight QuickTime demonstrates the normally-functioning centrifuge using both types of spray nozzles. It has some fun microgravity fluid effects.

In-flight Disaster QuickTime Movie

Description: This in-flight QuickTime demonstrates what happens when things go terribly, terribly wrong. Shots are taken from both in-flight cameras.

Seattle Times Newspaper Article

Description: This graphic from the Seattle Times demonstrates in an easy-to-understand format exactly how our experiment worked.



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