Automated Testing of the SAS-A Experiment

The small astronomy satellite (SAS-A) was placed into earth orbit in December 1970 with one experiment designed to scan the celestial sphere for sources of X-ray emission. An automated test procedure was used to confirm proper operation of all the experiment sensors and electronics prior to launch of the spacecraft. The testing that had to be conducted over the operational spacecraft telemetry and command channels from a remote location was automated by use of a general-purpose computer system. The computer was programmed to set the experiment into a predetermined configuration of sensor and electronic activation by commanding the spacecraft to turn on specific X-ray and electronic pulsetrain sources external to the experiment by commanding a source control unit, and to receive, decommutate, and process the telemetered experiment data from the spacecraft to produce a summary printout of test results for the experiment checkout engineer. The automated testing worked very well, greatly reducing the total time required to check out thoroughly the experiment portion of the spacecraft and allowing a comprehensive test and calibration of the experiment to be run during the actual launch countdown.