International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / This paper reviews the performance requirements that provided the baseline for
development of the onboard data system, RF transmission system, and ground segment
receiving system of the Midcourse Space Experiment (MSX) spacecraft. The onboard
Command and Data Handling (C&DH) System was designed to support the high data
outputs of the three imaging sensor systems onboard the spacecraft and the requirement for
large volumes of data storage. Because of the high data rates, it was necessary to construct
a dedicated X-band ground receiver system at The Johns Hopkins University Applied
Physics Laboratory (APL) and implement a tape recorder system for recording and
downlinking sensor and spacecraft data. The system uses two onboard tape recorders to
provide redundancy and backup capabilities. The storage capability of each tape recorder
is 54 gigabits. The MSX C&DH System can record data at 25 Mbps or 5 Mbps. To meet
the redundancy requirements of the high-priority experiments, the data can also be
recorded in parallel on both tape recorders. To provide longer onboard recording, the data
can also be recorded serially on the two recorders. The reproduce (playback) mode is at
25 Mbps. A unique requirement of the C&DH System is to multiplex and commutate the
different output rates of the sensors and housekeeping signals into a common data stream
for recording. The system also supports 1-Mbps real-time sensor data and 16-kbps real-time
housekeeping data transmission to the dedicated ground site and through the U.S. Air
Force Satellite Control Network ground stations. The primary ground receiving site for the
telemetry is the MSX Tracking System (MTS) at APL. A dedicated 10-m X-band antenna
is used to track the satellite during overhead passes and acquire the 25-Mbps telemetry
downlinks, along with the 1-Mbps and 16-kbps real-time transmissions. This paper
discusses some of the key technology trade-offs that were made in the design of the system
to meet requirements for reliability, performance, and development schedule. It also presents some of the lessons learned during development and the impact these lessons will
have on development of future systems.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/608390 |
| Date | 10 1900 |
| Creators | DeBoy, Christopher C., Schwartz, Paul D., Huebschman, Richard K. |
| Contributors | The Johns Hopkins University |
| Publisher | International Foundation for Telemetering |
| Source Sets | University of Arizona |
| Language | en_US |
| Detected Language | English |
| Type | text, Proceedings |
| Rights | Copyright © International Foundation for Telemetering |
| Relation | http://www.telemetry.org/ |
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