Leopoldo Rossini, CSEM, Switzerland
When launching satellites to orbit, every gram of payload is extremely valuable. Depending on the orbit and the launcher, an estimated cost is about 15,000 euros per kilogram. With this in mind, researchers at CSEM, the Swiss Center for Electronics and Microtechnology, are working on ways to minimise the weight of satellite attitude control systems. Here, a single multi-axis reaction sphere is proposed to replace four conventional single-axis reaction wheels. Its geometry and electromagnetic design are quite complex, and only with the help of COMSOL Multiphysics are they able to examine various configurations of magnets to find the one that works best.
Founded in 1984, by grouping three former watch-industry research laboratories, CSEM is now a private applied research and development centre specialising in micro technology, system engineering, micro electronics and communication technologies. With headquarters in Neuchâtel, it has some 400 employees in Switzerland.
Until Now: Multiple Reaction Wheels
In conventional 3-axis stabilised spacecrafts, three reaction wheels are arranged along the three axes, with a fourth wheel for optimisation and redundancy; they are normally employed to implement attitude control systems with the required accuracy and without using fuel to fire jets. This attitude control allows the satellite to be pointed towards an object in the sky, towards a particular location on earth or to stabilise the satellite by compensating for disturbances it might encounter.