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CL 01-0573


Honorable Mention: 1999 NASA Software of the Year Competition


aspen plug-and-play logo

A number of successful applications of automated planning and scheduling of spacecraft operations have recently been reported in the literature. However, these applications have been one-of-a-kind applications that required a substantial amount of development effort. The Artificial Intelligence Group at JPL has been working on a system called ASPEN (Automated Scheduling and Planning ENvironment). Based on AI techniques, ASPEN is a modular, reconfigurable application framework which is capable of supporting a wide variety of planning and scheduling applications. ASPEN provides a set of reusable software components that implement the elements commonly found in complex planning/scheduling systems, including: an expressive modeling language, a resource management system, a temporal reasoning system, and a graphical interface.

AI Technology


diagram of sequencing problem for spacecraft

The basic problem is to develop a sequence of commands for a system that achieves the objectives of the user of that system. The user (e.g., scientist) has some high-level objectives, or goals. Typically, the system (e.g., spacecraft) has a low-level command interface. Therefore, the problem becomes translating the high-level goals into a valid sequence of low-level commands. At JPL, some of the primary systems that require commanding are: deep-space probes, planetary rovers, and deep-space communication antennae.


Automated planning/scheduling technologies have great promise in reducing operations cost and increasing the autonomy of aerospace systems. By automating the sequence generation process and by encapsulating the operation specific knowledge, we hope to allow spacecraft commanding by non-operations personnel, hence allowing significant reductions in mission operations workforce with the eventual goal of allowing direct user commanding (e.g., commanding by scientists).



diagram of using aspen to manage spacecraft

ASPEN is a modular, re-configurable application framework based on Artificial Intelligence techniques, which is capable of supporting a variety of planning and scheduling applications including spacecraft operations planning, planning for mission design, surface rover planning, ground antenna utilization planning, and coordinated multiple rover planning.

As a ground based system, ASPEN uses an internal spacecraft model and set of high level goals to output a sequence of commands to be executed by the spacecraft to achieve those goals. As a flight-based system, ASPEN receives updates on spacecraft or rover state continuously and updates the current plan to reflect environment changes. As an antenna scheduling system, ASPEN has been used to autonomously control a DSN station.


ASPEN contains several innovations that are not available in other planning and scheduling systems in use today. Among those, the following are the most significant:

These innovations are documented and detailed in the 29 peer-reviewed publications 6 NASA Technology Briefs, 5 NASA Software Awards, and 4 JPL NOVA Technology Awards related to ASPEN technology. Additionally, patent status is pending on several of the Technology Briefs.




ASPEN - Automating Space Mission Operations using Automated Planning and Scheduling S. Chien, G. Rabideau, R. Knight, R. Sherwood, B. Engelhardt, D. Mutz, T. Estlin, B. Smith, F. Fisher, T. Barrett, G. Stebbins, D. Tran International Conference on Space Operations (SpaceOps 2000). Toulouse, France. June 2000
Using Iterative Repair to Improve Responsiveness of Planning and Scheduling S. Chien, R. Knight, A. Stechert, R. Sherwood, G. Rabideau International Conference on Artificial Intelligence Planning Systems (AIPS 2000). Breckenridge, CO. April 2000
Using Generic Preferences to Incrementally Improve Plan Quality G. Rabideau, B. Engelhardt, S. Chien International Conference on Artificial Intelligence Planning Systems (AIPS 2000). Breckenridge, CO. April 2000 + PDF CL#00-0399
Using Iterative Repair to Increase the Responsiveness of Planning and Scheduling for Autonomous Spacecraft S. Chien, R. Knight, A. Stechert, R. Sherwood, G. Rabideau International Joint Conference on Artificial Intelligence Workshop on Scheduling and Planning meet Real-time Monitoring in a Dynamic and Uncertain World. (IJCAI 1999). Stockholm, Sweden. August 1999
Iterative Repair Planning for Spacecraft Operations in the ASPEN System G. Rabideau, R. Knight, S. Chien, A. Fukunaga, A. Govindjee International Symposium on Artificial Intelligence Robotics and Automation in Space (ISAIRAS 1999). Noordwijk, The Netherlands. June 1999 + PS + PDF CL#99-0863
Towards an Application Framework for Automated Planning and Scheduling A. Fukunaga, G. Rabideau, S. Chien, D. Yan International Symposium on Artificial Intelligence, Robotics and Automation for Space. Tokyo, Japan. July 1997


ASPEN Technical Contact: Gregg Rabideau
Gregg.Rabideau at
JPL Technical Contact: Dr. Steve Chien
Steve.Chien at
Software Licensing:


Autonomy program, Dave Atkinson (JPL) managing.

Also Sponsored By:
Directors Research Discretionary Fund
Jet Propulsion Laboratory
California Institute of Technology