Coordinated Multisource Maintenance on Demand (CMMD)

Abstract
This effort develops the capability for integrated supply chain logistics and mission supportability through the use of advanced, on-demand, maintenance planning and scheduling technology. This has applications to a variety of Space Exploration mission scenarios for Crew Exploration Vehicle (CEV) and other Constellation systems including fleets of unmanned and manned vehicles and robotic probes. CMMD will help NASA address situations in which achieving mission goals requires balancing between multiple sources of demands, both operational and maintenance, on available resources.

Goals and Objectives
Research and exploration operations in space require planning and scheduling a broad range of different activities. Examples include crew activities, scientific tasks, spacecraft command and control, and tasking of robots. Each of these activities has very different characteristics, and will likely be managed using separate software systems. However, they all also interact with maintenance activities. Integration and coordination among all the software systems is essential. Otherwise, it becomes very difficult to adapt maintenance schedules to other activities and to adapt those other activities’ schedules to critical maintenance considerations.

In addition to scheduling maintenance activities, it is also necessary to alert crewmembers to potential problems that cannot be immediately corrected, so they can work around problems as needed and avoid using equipment in ways that would be unsafe. This communication must take into account the urgency of the problem, to avoid inundating the crew with minutia that might distract them from more pressing problems.

The CMMD technology has impact at many levels, influencing the design of equipment (hardware and software to monitor and communicate status), robots (ability to perform inspections and suggest maintenance), information and knowledge bases both for maintaining information about various components and sub-components and for recording their health status, and planning and scheduling systems used throughout the mission (integration into a distributed collaborative system).

Relation of Goals and Objectives to Human & Robotic Technology
In the future, manned space exploration teams will be supported by a large cadre of partly- (but not necessarily fully-) interchangeable mobile manned and robotic devices. In that environment, maintenance demands will stem from multiple competing sources which need to be reconciled. These competing sources include: (1) prognostic drivers from Integrated Vehicle Health Monitoring systems producing proactive condition-based "maintain me" demands, (2) maintenance management systems tracking usage and producing scheduled maintenance demands, (3) unscheduled maintenance demands resulting from any trouble reports entered by human observers of conditions missed by the IVHM system, and (4) implicit maintenance demands resulting from mission plans which require assignment of vehicular/robotic assets and consequently require assurance of the assigned assets' fitness for the intended tasks.

Our approach balances the concerns driving competing demands for maintenance within and across assets. It does so via a task planning and scheduling system for vehicle maintenance that manages communications between operations scheduling and maintenance scheduling systems. The result is a distributed collaborative system in which planning and scheduling of maintenance for assets is driven by the needs of the operational activities. By assuring that
maintenance is coordinated with operational requirements; our system simultaneously optimizes operational readiness and effectiveness while reducing sustained engineering costs.

Technical Challenges
The effort extends a previously-proven technology base by adding three new abilities: