The ASPEN Modeling Language (AML) has been developed for use in the Automated Scheduling and Planning Environment (ASPEN) software system. As described in prior NASA Tech Briefs articles, ASPEN is an object-oriented system that contains a modular, reconfigurable, reusable set of components that implement the elements commonly found in complex automated-scheduling application programs. AML has a simple syntax that makes it easy for a user who lacks expertise in computer science and artificial intelligence to rapidly create a model of a spacecraft-operations domain for an ASPEN automated-scheduling application program. AML enables a user to construct a model, expressed as a plain-text file, that defines activities, resources, and states. A user can also modify a model without need to recompile ASPEN. AML encodes spacecraft operability constraints, flight rules, spacecraft hardware models, goals of scientific experiments, and operational procedures to enable the generation, by the automated-scheduling program, of low-level sequences of spacecraft operations.
This program was written by Robert L. Sherwood, Alex Fukunaga, David Yan, Quoc Vu, Gregg Rabideau, Steve Chien, and Anita Govindjee 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-20281.
This Brief includes a Technical Support Package (TSP).
Programming Language for Automated Scheduling and Planning
(reference NPO-20281) is currently available for download from the TSP library.
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Overview
The document discusses the application of an automated planning and scheduling system called ASPEN (A Scheduling and Planning Environment) for the NASA Earth Orbiting 1 (EO-1) mission. Developed by the Artificial Intelligence Group at the Jet Propulsion Laboratory (JPL), ASPEN is a modular and reconfigurable application framework that leverages artificial intelligence techniques to enhance the autonomy of mission operations, thereby reducing operational costs.
EO-1, an Earth imaging satellite launched in May 1999, is equipped with an advanced multi-spectral imaging device. The mission's operations involve managing various spacecraft constraints, including power, thermal conditions, pointing, bus systems, consumables, and telecommunications. The primary goal of the EO-1 mission is to capture images of specific targets under defined observation parameters.
The document outlines the structure of the ASPEN system, which includes a modeling language that allows users to encode spacecraft operations and activities. The modeling language facilitates the definition of activities, resources, and their interrelationships, enabling the automated scheduling of daily satellite operations. The system is designed to handle different types of resources, categorized as atomic, concurrency, depletable, and non-depletable. Atomic resources can only be reserved by one activity at a time, while non-depletable resources can be used by multiple activities simultaneously without needing replenishment. Depletable resources, on the other hand, diminish with use and may or may not be replenished.
The document also highlights the importance of constraints in scheduling, such as temporal relationships between activities and resource availability. It explains the difference between constraints and subactivities, emphasizing that constraints can be satisfied by any activity in the schedule, while subactivities are defined within a parent activity and must adhere to specific resource constraints.
In conclusion, the document presents a comprehensive overview of the ASPEN system and its application in the EO-1 mission, showcasing its potential to improve the efficiency and autonomy of satellite operations through advanced planning and scheduling capabilities. The work described was conducted under contract with NASA, emphasizing the collaboration between JPL and the agency in advancing space exploration technologies.
