Citation
Abstract
The impact of a multiple-rate command capability on the present end-to-end ground spacecraft command system has been studied. Limitations in the present command system include a maximum average command word (71 bits or less) transfer rate of 1 word per second and a mean time between failure of 13 hours for the ground portion of the system. Command rates are currently set by end-ofmission (EOM) requirements. Adding a multiple-rate command capability to the present spacecraft command subsystem would result in more reliable flight computer updates during mission phases which could support higher than EOM command rates. During non-catastrophic spacecraft anomalies, commanding could be made more reliable by decreasing the command data rate below EOM requirements. In addition, a flexibility of command rate could be used to optimally apportion command activity between the 26-m and 64-m antenna Deep Space Stations when multiple-spacecraft missions are in progress. The increase in hardware cost necessary to implement a multiple-rate command capability is estimated to be less than 1% of that of current command flight hardware.
Details
- Volume
- 42-25
- Published
- February 15, 1975
- Pages
- 94–107
- File Size
- 1.3 MB