Flight-Ground Integration - The Future of Operability

Abstract

Flight and ground integration is an ongoing challenge in the development of deep space mission operations systems. Separate development teams and schedules exacerbate the problem. Enhancing the operability of the flight and ground interactions has proven to be a strategy that reduces both cost and risk. One of the first areas to be addressed was the commanding and sequencing system. VML (Virtual Machine Language) sequencing was developed to improve operability and has now been used as the sequencing flight software on fifteen NASA deep-space missions, most recently on NASA's Mars Atmosphere and Volatile EvolutioN (MAVEN) mission. In conjunction with the NASA SBIR "Reactive Rendezvous and Docking Sequencer", VML 3.0 has been enhanced to include synchronizable state machines, object-oriented element organization, and sophisticated matrix/vector operations. These improvements allow VML scripts to perform much of the work that formerly would have required expensive flight software development. Sophisticated high-level VML state machines provide autonomous management of critical spacecraft operations, and perform replanning activities to take advantage of targets of opportunity. VML state machines replace sequences with reactive logic constructs capable of autonomous decision making within their prescribed domain. These new capabilities in VML 3.0 continue a long tradition of enhancing the flight-ground interface in simple and powerful ways. I. Mission Operations DomainThe mission operations domain of a deep space mission encompasses both the development of the system used to carry out operations, and the conduct of the operations phase of the mission itself. A Mission Operations System (MOS) is comprised of a Ground Data System (GDS), which includes the software, hardware, networks, facilities of the domain, plus the MOS teams, policies, processes, procedures, and training. Figure 1 shows the basic operations functions carried out for a deep space mission.It is essential to view deep space mission operations as a function of the mission objectives. Seen in this way, operations can be thought of as consisting of three items, in priority order:1. Collect science data (to achieve the mission objectives) 2. Operate the flight system (to collect science) 3. Build, test, and deliver the flight system to orbit (in order to have a platform to operate) In order for operations personnel achieve the second priority, they must successfully operate the flight system to collect science data. The more operable the flight system, the simpler and more reliable the operations team's job becomes. During development, however, it is easy to lose sight of mission objectives in the drive to build and launch the flight system. What may be lost is a focus on the achievement of the mission objectives that can only be accomplished via operation of that system. Operable flight systems are more likely to reach the objectives, and keep cost and risk down as well.