The command- and-data- handling (C&DH) software of the Wilkinson Microwave Anisotropy Probe (WMAP) spacecraft functions as the sole interface between (1) the spacecraft and its instrument subsystem and (2) ground operations equipment.

This software includes a command-decoding and -distribution system, a telemetry/ datahandling system, and a data-storage-and- playback system. This software performs onboard processing of attitude sensor data and generates commands for attitude-control actuators in a closed-loop fashion. It also processes stored commands and monitors health and safety functions for the spacecraft and its instrument subsystems. The basic functionality of this software is the same of that of the older C&DH software of the Rossi X-Ray Timing Explorer (RXTE) spacecraft, the main difference being the addition of the attitude-control functionality. Previously, the C&DH and attitude-control computations were performed by different processors because a single RXTE processor did not have enough processing power. The WMAP spacecraft includes a more-powerful processor capable of performing both computations.

This program was written by Alan Cudmore, Tim Leath, Art Ferrer, Todd Miller, Mark Walters, Bruce Savadkin, and Ji-Wei Wu of Goddard Space Flight Center; Steve Slegel of Daedalian Systems Corp.; and Emory Stagmer of Litton/PRC.


NASA Tech Briefs Magazine

This article first appeared in the September, 2007 issue of NASA Tech Briefs Magazine.

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