One task of the navigation and control systems department is to develop and verify satellite attitude control systems. The F.A.C.E. facility was designed to meet this objective. One main task is to create an artificial surrounding, which simulates the environmental conditions in space (zero gravity, magnetic field, solar radiation, earth albedo, stellar background) as well as possible.
The most difficult condition to simulate is the force free rotation of the satellite body. This is difficult to achieve on the Earth’s surface since gravity always affects the satellite body. However, a trick is used to create realistic satellite motion on Earth: an air-bearing table.
The air-bearing table is an assembly platform on which a perfect hemisphere (callote) is installed. On the opposite side of the embedded callote is a stator. A thin cushion of air separates the callote and the stator, making the callote act as an air bearing. In this manner the assembly platform can spin almost frictionless around all three axes. The effects of zero gravity can by simulated by using this trick.
The F.A.C.E. facility can also generate a realistic magnetic environment using a Helmholtz coil set-up. This consists of six circular magnet coils installed around the air-bearing table. With the help of these coils an artificial magnetic field is generated simulating the conditions in Earth orbit. Additionally, the facility can generate artificial solar radiation, in which light from a studio spotlight can be shined via a mirror onto the assembly platform.
The actual components of the attitude control system are mounted onto the air-bearing table’s platform. Thus a nearly self-sustaining satellite is arranged on the platform which can be subjected to various tests.