Ron Noteborn

PRISMA: An In-Orbit Test Bed for Guidance, Navigation, and Control Experiments

This paper presents system-level hardware-in-the-loop real-time simulation results for three different guidance, navigation, and control experiments designed for in-flight demonstration on the PRISMA formation-flying satellite mission. The mission consists of two spacecraft: Main and Target The Main satellite has full orbit control capability, whereas Target is attitude-controlled only. Launch is planned for November 2009. The simulation results presented demonstrate the feasibility and readiness for flight as well as the expected in-flight performance. The three experiments include Global Positioning System and vision-based formation flying for two spacecraft in both passive and forced motion. In addition to these simulation results, the paper gives an overview of the PRISMA mission in general and the guidance, navigation, and control experiments in particular. The hardware-in-the-loop real-time test environment is also presented.

PRISMA: An In -Orbit Test Bed for GNC Experiments

The PRISMA formation flying satellite project will demonstrate Guidance, Navigation, and Control strategies for advanced autonomous formation flying. The Swedish Space Corporation (SSC) is the prime contractor for the project which is funded by the Swedish National Space B oard (SNSB). By mid 2008, PRISMA is well into the system integration and test campaign and launch is planned for June, 2009. The mission consists of two spacecraft: MAIN and TARGET. The MAIN satellite has full orbit control capability while TARGET is attitude controlled only. PRISMA will perform a series of GNC related formation flying experiments. SSC is responsible for three main sets of experiments: Autonomous Formation Flying, Proximity Operations and Final Approach/Recede Maneuvers, and Autono mous Rendezvous. This paper focus es on describing these three set s of formation flying experim ents. The system test setup is also described together with real -time system level test results demonstrating the performance of each of the three GNC experiment sets.

Prisma Mission Extension: Adapting Mission Operations to New and Changing Mission Objectives

The PRISMA in-orbit test-bed was launched in June 2010 to demonstrate strategies and technologies for formation flying and rendezvous. OHB Sweden is the prime contractor for the project which is funded by the Swedish National Space Board (SNSB) with support from DLR, CNES, and DTU. In early September of 2011, 15 months after launch, all primary mission objectives of the PRISMA formation flying satellites had been achieved and mission success was declared. Since a significant amount of delta-V capability still remained an open call for new experiments was issued, inviting both old and new experimenters to use the capabilities of the formation. Several interested parties took the opportunity to perform their own experiments with an existing platform, each coming with new mission objectives not previously planned to be flown on the PRISMA satellites. Some of these experiments were close to what had already been achieved within the nominal mission, but some included new ways of using the formation not envisioned by the spacecraft designers. The new experiments span from data collection in specific relative orbits, with a separation from a few meters to several kilometers, to entirely new modules within the on-board software. Changing from a pre-planned technology demonstration mission to operating a commercial resource required adaptation of the original operational concept, taking into account the different levels of experience of the customers and managing the satellites between experiments. This paper describes how these new mission objectives were integrated in operations and how a sometimes very short turn-around between initial concept and experiment execution was implemented with the aid of well established validation processes, high degrees of on-board autonomy and a flexible operations team.