Low Cost Attitude Sensors for Spacecraft

A short overview is presented on low cost attitude sensors developed by Applied Research Corporation. More or less existing technology has been used, but major emphasis was directed to considerably reduce the cost of these units without compromising their quality and reliability. Horizon and sun aspect sensors have been developed and manufactured. They were successfully flown on the space shuttle Atlantis (STS 34, October 18, 1989). We have further manufactured 10 horizon sensors and 15 sun aspect sensors and delivered them to Goddard (Wallops) Space Flight Center for future use on sounding rockets. The angular errors are about ±0.1" to 0.2" for the horizon and sun aspect sensors. Their mass is about 0.3 to 0.8 kg and their power requirement about 0.1 to 1.5 W. We have recently won a contract with Goddard to develop a low cost star tracker with an angular error of about ±5 sec of arc. Our plan is to produce a protoflight unit of such a sensor in about 24 months. Some details of the results obtained from the shuttle flight and some system details will be presented.