Spaceborne Autonomous Formation-Flying Experiment on the PRISMA Mission

Abstract

The Prototype Research Instruments and Space Mission Technology Advancement (PRISMA) represents the first
\nEuropean technology demonstration of formation-flying and on-orbit-servicing techniques. Several hardware and
\nsoftware experiments, either at subsystem or system levels, have been successfully conducted since the launch of the
\ndual-satellite mission in June 2010. This paper describes the guidance, navigation, and control functionalities and
\npresents key flight results from the so-called Spaceborne Autonomous Formation-Flying Experiment (SAFE)
\nexecuted in September 2010 and March 2011 as one of the primary PRISMA mission objectives. SAFE is intended to
\ndemonstrate autonomous acquisition, keeping, and reconfiguration of passive relative orbits for advanced remotesensing
\nand rendezvous applications. As shown in the paper, the onboard Global Positioning System navigation
\nsystem provides relative orbit information in real time with an accuracy better than 10 cm and 1 mm=s (threedimensional,
\nroot mean square) in position and velocity, respectively. The impulsive formation control achieves
\naccuracies better than 10m(three-dimensional, root mean square) for separations below 2 km with minimum usage
\nof thrusters, ensuring high predictability for simplified mission operations and minimum collision risk for increased
\nsafety.