Coordination (ShAC) is a computer program for planning and scheduling the activities of an autonomous team of interacting spacecraft and exploratory robots. ShAC could also be adapted to such terrestrial uses as helping multiple factory managers work toward competing goals while sharing such common resources as floor space, raw materials, and transports. ShAC iteratively invokes the Continuous Activity Scheduling Planning Execution and Replanning (CASPER) program to replan and propagate changes to other planning programs in an effort to resolve conflicts. A domain-expert specifies which activities and parameters thereof are shared and reports the expected conditions and effects of these activities on the environment. By specifying these conditions and effects differently for each planning program, the domain-expert subprogram defines roles that each spacecraft plays in a coordinated activity. The domain-expert subprogram also specifies which planning program has scheduling control over each shared activity. ShAC enables sharing of information, consensus over the scheduling of collaborative activities, and distributed conflict resolution. As the other planning programs incorporate new goals and alter their schedules in the changing environment, ShAC continually coordinates to respond to unexpected events.
This program was written by Bradley Clement of Caltech for NASA's Jet Propulsion Laboratory . For further information, access the Technical Support Package (TSP) free on-line at www.techbriefs.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-30614.
This Brief includes a Technical Support Package (TSP).
Coordinating Shared Activities
(reference NPO-30614) is currently available for download from the TSP library.
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Overview
The document is a Technical Support Package from NASA's Jet Propulsion Laboratory, focusing on the coordination of shared activities in aerospace missions through the ShAC software. ShAC, which stands for Shared Activity Coordination, is designed to manage multiple CASPER (Continuous Activity Scheduling Planning Execution and Replanning) planning systems. It facilitates collaboration among different spacecraft or explorers by allowing them to share activities, resources, and states, thereby enhancing mission efficiency and effectiveness.
The core functionality of ShAC involves the iterative invocation of CASPER planners to replan and propagate changes across the various systems involved. This process helps resolve conflicts that may arise over shared resources or local states, ensuring that all participating entities are aligned in their activities. A domain expert plays a crucial role in this system by specifying which activities are shared, the parameters associated with these activities, and the expected conditions and effects on the environment. This specification allows for the definition of distinct roles for each spacecraft during coordinated activities.
Additionally, the domain expert can designate which planner has control over scheduling for each shared activity, further enhancing the coordination process. This capability allows for continuous mission coordination, whether managed from the ground or autonomously by onboard planners.
The document emphasizes the broader implications of this technology, suggesting that the advancements in coordinating shared activities have potential applications beyond aerospace, possibly extending into various technological, scientific, or commercial fields. It highlights NASA's commitment to making the results of aerospace-related developments accessible to a wider audience through the Commercial Technology Program.
For those seeking further information, the document provides contact details for the NASA Scientific and Technical Information (STI) Program Office, where additional resources and publications can be accessed. Overall, the Technical Support Package underscores the importance of effective coordination in complex missions and showcases NASA's innovative approaches to enhancing collaborative efforts in space exploration.
