Original Date: 04/26/1999
Revision Date: 01/18/2007
Best Practice : Real-Time Expert Systems for Spacecraft Health Monitoring and Command
NASA realizes that its current approach to payload operations will be significantly changed because of continuing fiscal pressures. Since 1994, Marshall Space Flight Center (MSFC) has funded the development of intelligent software applications for payload ground operations. These applications offer a way to reduce labor requirements so long-term operations, like International Space Station (ISS), can be effectively managed. Through deployments, the Mission Operations Laboratory (MOL) has already demonstrated the benefits of intelligent software systems for real- time telemetry monitoring and commanding.
G2 is the technology that enables object-oriented development of software applications, so MSFC can create intelligent control and diagnostic monitoring systems in a time-critical environment. This technology operates on Unix workstations and Windows NT PCs, and incorporates commercial-off-the-shelf (COTS) software and an Optimized Advanced System Integration and Simulation (OASIS) programming shell. MSFC uses G2 across its program lifecycles, and integrates lifecycle data into this tool as libraries (Conceptual; Requirements; Design; Fabrication and Test; Training and Operations). This Common Lifecycle Toolset features sub-elements and reusable software steps which will evolve into the operational fidelity phase (optimal level of certainty) for life-critical decisions. G2’s operator interface is done through text language and simulation technology. Because of the interface’s flexibility and intuitiveness, no extensive knowledge of programming is required. Inference knowledge and generic object libraries, combined with OASIS, create several advantages for efficiencies and project costs related to programming.
During mission operations, a real-time expert system provides schematic-based telemetry monitoring, data trending, expected state monitoring, malfunction procedure execution, and high/low (analog) monitoring. Updated once per second, the system displays operator messages via graphics and prioritizes faults by using color schemes. Ground control personnel can monitor the system via remote, through the MOL, or with routed messages (e.g., e-mail, pager) based on predetermined parameters. In addition, faults are quickly traced to the component level through point-and- click commands, which provides the engineer with additional minutes for resolving a problem.
MSFC’s integrated systems engineering approach enhances design knowledge capture and retention for all mission phases, and allows the development cycle to be accelerated. By using G2, the MOL reduced labor needs, promoted communications, and achieved a ten-fold increase in productivity.
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