Modernizing the NASA Space Network Ground Systems for Centralized Management and Control of Distributed Shared Resources

摘要

One of the most challenging problems facing designers and developers who are upgrading space network ground systems is ensuring that the system maintains support for existing customer spacecraft (also known as legacy spacecraft) while replacing obsolete components and subsystems on the ground. NASA's SNGS supports spacecraft that are decades old, and the SNGS has evolved at pace with the needs of these user spacecraft. Applying modern network solutions to space network ground systems requires that specific attention be paid to two major design areas: first, where can commercial functions be easily leveraged (e.g., switch replacement); and second, where is more complex evaluation needed to provide equivalent performance at the system boundary as opposed to identical functionality within the bounds of the system. To address this challenge, the modernization of the SNGS includes flexible, dynamic resource control of ground segment components within a layered architecture. Such a design accommodates both legacy (older) and unique (not necessarily older) functionality without excluding modernization and future functionality. For the SNGS, it was determined that these needs were best addressed by creating zones of pooled resources that are controlled relatively genetically at the highest -most central - level (e.g., system capacity analysis/scheduling), with increasing specificity and detail as control mechanisms get closer to assignable resources. The SNGS uses Service Oriented Architecture (SOA)-based architectural solutions and mechanisms to support legacy components without sacrificing future enhancement and expansion. It further uses standard protocols and formats - particularly SOA-based ones - such as extensible Markup Language (XML) to communicate SNGS control and management information among the various control and management levels.