The goal of this work was to model lunar surface systems using a declarative planning system (ASPEN — Activity Scheduling/Planning Environment), provide a parameterizable Excel document to aid in the model generation, and deliver both Mac and PC versions. An adaptation of Microsoft Excel and ASPEN for Lunar Surface System concepts of operations was used. The goal of the system is to enable searching through several concepts of operations. A concept of operations consists of a proposed schedule of high-level activities and parameterization of resources (e.g., power, communications, oxygen, water, etc.) where three distinct phases of development occurred: (1) initial system development for Lunar, (2) planning system development for Lunar, and (3) planning system development for NASA’s 13th Desert Research and Technology Studies (Desert RATS) live trial.
ASPEN is a modular, reconfigurable application framework based on artificial intelligence techniques that 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 control autonomously a DSN station.
ASPEN contains several innovations that are not available in other planning and scheduling systems in use today. The ASPEN system does not require any user knowledge in the areas of computer programming, planning, or scheduling. At the same time, the language is flexible enough to support the complex needs of planning multiple spacecraft and resources.
ASPEN contains a generic architecture that allows the user to choose among several different search engines and propagation algorithms to optimize the planning process. It contains an iterative repair search algorithm that enables the user to interact with the schedule and replan quickly and efficiently. The plans that ASPEN generates can be optimized for a specific set of goals, such as maximizing science data or minimizing power consumption. The optimization goals can be easily and succinctly specified within the modeling language.
ASPEN had been adapted to many domains, but this is the first time it was adapted to human lunar operations. The small delivery footprint of ASPEN (less than 10Mb), combined with the expressivity and power of the planning engine, makes it uniquely suited for the task of concept of operations evaluation.
This work was done by Russell L. Knight, Sharon L. Laubach, Robert Gershman, Grailing Jones Jr., Brian K. Bairstow, Micheal A. Seibert, and Gene Y. Lee of Caltech for NASA’s Jet Propulsion Laboratory.
The software used in this innovation is available for commercial licensing. Please contact Dan Broderick at
This Brief includes a Technical Support Package (TSP).
Modeling Lunar Surface Systems Concepts of Operations
(reference NPO-48214) is currently available for download from the TSP library.
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Overview
The document outlines the development and application of the ASPEN (Automated Scheduling and Planning ENvironment) system by the Jet Propulsion Laboratory (JPL) for planning and scheduling lunar surface operations. ASPEN is a modular, AI-based framework designed to automate the generation of command sequences for spacecraft, enabling non-operations personnel, such as scientists, to command spacecraft more efficiently.
The planning system was initially developed to address energy oversubscription issues related to power use during idle periods of crewed rovers. It evolved to diagnose crew sleep duration violations, where the scheduling of activities could lead to insufficient rest for crew members. The system's adaptability was demonstrated during the Desert RATS (Research and Technology Studies) project, where it modeled the constraints and operations of lunar systems, allowing for a comparison between actual and hypothetical lunar scenarios.
The document details the evolution of power models used in the project, which began as simple representations of power use and developed into more sophisticated systems capable of managing power suppliers and consumers effectively. The final planning system incorporated intelligent power management strategies, which were crucial for ensuring that power systems could support the operational needs of the crew without exceeding their limits.
Additionally, the document discusses the compatibility of ASPEN and Excel with both Windows and Mac platforms, highlighting challenges faced during development, such as adapting Visual Basic for Applications (VBA) scripts for cross-platform functionality. The successful adaptation of these tools provided actionable intelligence for various hypothetical scenarios, demonstrating the importance of intelligent power management and synchronization of crew activities.
Key findings from the project included the identification of scenarios where naive power management led to operational challenges and the realization that crew sleep was compromised due to the need for resynchronization of plans among crew members executing parallel tasks. The document concludes by emphasizing the potential of automated planning and scheduling technologies to reduce operational costs and enhance the autonomy of aerospace systems, ultimately supporting future lunar missions.
Overall, the document serves as a comprehensive overview of the advancements in planning and scheduling for lunar surface operations, showcasing the integration of technology and innovative approaches to address complex challenges in space exploration.
