The recovery of the HEAO-2 observatory
Abstract
In August 1980, the Second High Energy Astronomy Observatory suffered the simultaneous double failure of two gyros, leaving the observatory with one gyro less than what is required for operation. The function of the missing gyro was replaced to allow restoration of spacecraft operation by reprogramming the on-board computer to derive rate from star and sun sensors, and by utilizing complex procedures. Large sun sensor quantization, jump characteristics of the star tracker, and extremely limited computer memory capacity further complicated the problem. Recovery attempts continued for over three months, during which time a suitable rate algorithm was derived. Final verification of the technique was never completed, however, due to the unexpected revival of one of the failed gyros.
- Publication:
-
In: Guidance and control 1981; Proceedings of the Annual Rocky Mountain Guidance and Control Conference
- Pub Date:
- 1981
- Bibcode:
- 1981guco.proc..339R
- Keywords:
-
- Airborne/Spaceborne Computers;
- Computer Systems Programs;
- Gyroscopes;
- Heao 2;
- Numerical Control;
- Spacecraft Control;
- Computer Storage Devices;
- Failure Analysis;
- Mathematical Models;
- Onboard Data Processing;
- Solar Sensors;
- Star Trackers;
- Launch Vehicles and Space Vehicles