August 2005, Issue 181

Flight Computer for High-Power Rocketry

If you’re interested in rocketry, you’ve probably seen the movie October Sky (1999). Or perhaps you’ve read Homer Hickam’s book Rocket Boys (1998), the memoir on which the movie is based. It’s a story about both a boy’s dream to discover our heavens and the days of early amateur rocketry. Can it get any better than that?

Today, amateurs are taking rocketry to the next level. Groups like the National Association of Rocketry (NAR), Tripoli, the Civilian Space eXploration Team (CSXT), and Scaled Composites are working to expand our knowledge of amateur rocketry. Some of the people involved have claimed the big X PRIZE; others have been after the challenge of speed, altitude, and a safe recovery.

High-tech components are now pushing into the realm of amateur rocketry, which has become more sport than hobby. Rockets include RF/GPS tracking systems, on-board flight cameras (video and still), and flight computers for measuring speed, temperature, and altitude. Dual-deployment computers control the release of parachute systems, which some insiders call “laundry.” Timing systems control the staging of a multistage rocket (or “air starts”). Universities are using high-power rocket payload bays to test small satellite components. Refer to the CubeSAT program for more information (http://cubesat.calpoly.edu).

After building a high-power rocket of my own, I wanted to add some high-tech gadgetry to the system. I really wanted a flight computer that could measure the rocket’s acceleration, altitude, and temperature, and then record the data on a serial flash memory device. Rather than spend the money on an off-the-shelf flight computer, I designed my own.

In this article, I’ll describe how I built my Zilog Z8-based ZSAT flight computer. With this system, I can retrieve useful flight data on my cell phone. No laptop computer required. I’ll also explain how you can get involved in high-power rocketry.