The Validation and Testing of the PRISMA Formation Flying Project

Paper number

IAC-08.B4.2.2

Author

Mr. Staffan Persson, Swedish Space Corporation, Sweden

Coauthor

Mr. Ron Noteborn, Swedish Space Corporation, Sweden

Coauthor

Mr. Simone D'Amico, Germany

Coauthor

Mr. Jon Harr, CNES, France

Coauthor

Mr. Michel Delpech, CNES, France

Year

2008

Abstract

The PRISMA technology demonstration mission for autonomous formation flying and rendezvous technology is currently undergoing integrated system testing. The project comprises two satellites which will be launched clamped together and separate in orbit. The satellites then constitute an in-orbit test bed for Guidance, Navigation and Control (GNC) algorithms and sensors for advanced formation flying and rendezvous. Several experiments involving GNC algorithms, sensors (GPS, RF and vision based) and thrusters, will be performed during a 10 months mission with launch planned for mid of 2009. 
The project is run by the Swedish Space Corporation (SSC) with important support from the German Aerospace Center (DLR), the French Space Agency (CNES) and the Technical University of Denmark (DTU). Additionally, the project will also serve as a flight demonstrator for two novel motor technologies: One that uses environmentally clean and non-hazardous propellant, and one that consists of a microthruster system based on MEMS technology.
The paper will give an overview of the validation and test activities for the GNC experiment scenarios. These activities comprise open and closed loop testing on different levels. Closed loop simulations are mainly carried out in the real-time simulation facility, also called Satlab. In its simplest form Satlab consists of three main components. First of all it includes an onboard computer core board (based on a LEON-3 microprocessor) and a TM/TC board for each satellite. This equipment enables the execution of the flight software under extremely realistic conditions, in terms of memory load and computational performance. Second Satlab integrates a complete ground check-out and operations system called RAMSES. This system allows the operators to communicate with the PRISMA spacecraft via TM/TC in a real-world fashion, giving the possibility to test procedures, experiment timelines and in general mission operations rehearsals. Finally an advanced simulator simulates the orbit dynamics of both S/C, all the onboard units including the bus traffic, and the inter-satellite link traffic between the S/C. Additionally, closed-loop validation campaigns will be carried out involving the real satellite H/W in the loop. As an example the paper will present results from such simulations making use of a 2x12 channels Spirent GSS7700 GPS signal simulator as well as an RF metrology emulator especially designed for PRISMA. Together, the two H/W simulators are capable of generating L1 GPS signals and RF metrology signals for two independent vehicles.

Abstract document

IAC-08.B4.2.2.pdf

Manuscript document

IAC-08.B4.2.2.pdf (🔒 authorized access only).

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