Attitude Control System For SSETI ESMO
- Paper number
IAC-07-C1.I.01
- Author
Mr. Kristian Reiten, Narvik University College, Norway
- Coauthor
Mr. Rune Schalbusch, Norway
- Coauthor
Mr. David Hagen, Narvik University College, Norway
- Coauthor
Raymond Kristiansen, Narvik University College, Norway
- Coauthor
Dr. Per Johan Nicklasson, Narvik University College, Norway
- Year
2007
- Abstract
In this paper we present a study of the Attitude Control System (ACS), based on reaction wheels and thrusters, for the Student Space Exploration Technology Initiative (SSETI) European Student Earth Orbiter (ESEO). The SSETI project was founded in 2000, with great support from the European Space Agency (ESA) and lives by the idea that there are many universities that are capable of making hardware, but few who are capable of building a whole satellite. One of SSETI’s main objectives is therefore to create a network of students, educational institutes and organizations to design, construct and launch spacecrafts. The ESMO satellite project is a continuance of the SSETI Express satellite launched in 2005 and the European Student Earth Orbiter (ESEO) due to launch in 2008. ESMO is a 60 x 60 x 70 cm3 satellite with a weight of 150 kg, scheduled for launch into lunar transfer orbit in 2011, from where it will travel to and orbit the moon in search for ice. The ACS includes four reaction wheels in a tetrahedral configuration and four attitude thrusters mounted on the satellite base plate, two on each side of the Y and X axis of the satellite. The thrusters are angled +-45 deg relative to the X axis. The reaction wheels will mainly be used for orienting of the satellite, while the attitude thrusters will be used for momentum dumping of the reaction wheels and for de-tumbling. Nonlinear control theory is used to derive an integrator backstepping controller, which will be applied on the reaction actuators in the ESMO satellite. The derived controller is proved to render the equilibrium points in the closed-loop system asymptotically stable using Lyapunov theory, and controller performance and reliability, together with overall system pointing accuracy is shown via simulation. The analysis shows that the system is stabile and that the ACS is capable of stabilizing the satellite within the demanded pointing accuracy and time limits.
- Abstract document