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PLEXIL and Universal Executive Software Released Open Source

The Plan Execution Interchange Language (PLEXIL) and the Universal Executive (UE) have been released as open source software, available at Included in the release are the PLEXIL language definition (XML schemas), a compiler for the user-level PLEXIL programming language, the UE, interface and communication frameworks for connecting the UE to planners and controlled systems, a graphical plan execution viewer, example plans, and complete user documentation.

BACKGROUND: PLEXIL is a language for representing plans for automation. The Universal Executive (UE) is the implementation and execution engine for PLEXIL. PLEXIL and the UE, first developed in 2006, have been used to operate K10 planetary rovers (most recently in last month’s Moses Lake field test), provide an executive for the Drilling Automation for Mars Exploration (DAME) drilling application, and demonstrate automation for International Space Station operations as part of the Automation for Operations (A4O) project.

A4O is an ETDP-funded project with members from NASA’s Johnson Space Center (JSC), Langley Research Center (LaRC), Ames Research Center (ARC), and Jet Propulsion Laboratory (JPL), as well as SRI, United Space Alliance (USA), and TRACLabs (a JSC contractor). The project develops trusted adjustable automation technology to advance the state of the art in mission operations, crew self-scheduling, robotic operations, and systems operations for lunar outpost and surface infrastructure operations.

NASA PROGRAM FUNDING: This work was funded by the NASA Exploration Technology Development Program and the Mars Technology Program.

TEAM MEMBERS: Vijay Baskaran, Michael Dalal, David Espinosa, Chuck Fry, Michael Iatauro, C. Pasareanu, J. Frank, G. Brat (ARC); T. Estlin, V. Verma (JPL); C. Munoz (LaRC); R. Simmons (Carnegie Mellon University)

POC: Mike Dalal


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