A system of software has been designed to enable autonomous operations of the three University-built miniature spacecraft of the Three Corner Sat mission, scheduled for launch in 2003. The main software subsystems and their functions are the following:

  • The Spacecraft Command Language (SCL) robust-execution program will demonstrate aspects of low-level autonomy, including event-driven execution, local retries, low-level responses to faults, and validation of commands.
  • The Continuous Activity Scheduling Planning Execution and Replanning (CASPER) program will demonstrate onboard continuous planning to enable the 3CS constellation to respond to mission anomalies, mission opportunities, and onboard evaluations of scientific data, thereby utilizing feedback to integrate planning with execution.
  • A data-validation module will use heuristic methods to score utility of scientific images; CASPER will then use the utility scores in planning future operations, discarding images of lowest utility, and prioritizing downlink resources to send the best images first.
  • The Selective Monitoring (SELMON) anomaly-detection-and-isolation program will use empirically derived error bounds to enable context-sensitive detection of anomalies.
  • A package of basic spacecraft-coordination software will ensure that one of the spacecraft takes charge of maintaining the plan of operations for all three spacecraft.

This program was written by Barbara Engelhardt, Colette Wilklow, Gregg Rabideau, Robert Sherwood, Russell Knight, and Steve Chien of Caltech for NASA's Jet Propulsion Laboratory. For further information, access the Technical Support Package (TSP) free on-line at www.nasatech.com/tsp under the Software category.

This software is available for commercial licensing. Please contact Don Hart of the California Institute of Technology at (818) 393-3425. Refer to NPO-30277.

This Brief includes a Technical Support Package (TSP).
Software for Onboard Autonomy of a Three-Spacecraft Mission

(reference NPO-30277) is currently available for download from the TSP library.

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This article first appeared in the December, 2002 issue of NASA Tech Briefs Magazine.

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