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Collection InformationProceedings from the International Telemetering Conference are made available by the International Foundation for Telemetering and the University of Arizona Libraries. Visit http://www.telemetry.org/index.php/contact-us if you have questions about items in this collection.
AbstractThe Mission Operations Center (MOC) at APL is the first processing link in the MSX data system. Two key components of the MOC that play a role in the telemetry acquisition and processing functions are the Mission Control Center (MCC) and the Mission Processing Center (MPC). This paper will present a summary of the telemetry acquisition and data processing structure built to handle the high volume of MSX data and the unique hardware and software systems to perform these functions. The primary responsibility of the MCC is to maintain the health and safety of the MSX spacecraft. This is accomplished by communicating with the spacecraft through the APL stations and the AFSCN. The MCC receives the spacecraft housekeeping 16 Kb telemetry stream and commands the spacecraft via the 2K command link. Due to the complexity of the spacecraft various analysis tools exist to evaluate the spacecraft health and to generate commands for controlling the spacecraft. The primary responsibility of the MPC is the initial processing of the 1Mb and 25Mb spacecraft science telemetry streams. The science data is recorded in a raw format, both analog and digital, and a digital 8 mm tape format, Level 1A tape, which serves the MSX program as the transport media and format for science data dissemination. The MPC also collects downlink data from the MCC and planning products from the Operations Planning Center for inclusion on the Level 1A tape to enable the MSX data community to analysis the data. This data is sent electronically to the MPC via a LAN. One of the key products provided on the Level 1A tape from the MCC is a measure of the spacecraft clock against time standards. The MPC consists of a hardware front end for the capture and formatting of the science data and a computer system for the processing of the formatted science data to produce Level 1A tapes. The hardware front end includes wideband analog recorders, decryption devices, data selectors, bit sync, and frame syncs. One of the unique features of the 25 Mb telemetry stream is that is transmitted to the ground in the reverse direction. The MPC must then reverse the data again which is accomplished via analog recorders in order to perform further processing. The computer system consists of three model VAX 4000 computers with 107 Gb of disk space and 12 8 mm tape drives. One VAX is task with reading the 25 Mb telemetry onto the disk. The second VAX reads to the 1Mb telemetry onto the disk and produces a digital 8 mm tape of the raw data. The third VAX is tasks with processing the data and writing the Level 1A tapes. The systems architecture is such that while today's data is being downlinked yesterday's data is being processed and written to Level 1A tapes. Custom software was developed to perform the processing and data management within the MPC.
SponsorsInternational Foundation for Telemetering