DropCube - A platform for testing spacecraft attitude control systems

In recent years there has been a large increase in suggested controllers and observers for attitude determination and control of rigid bodies such as spacecraft. On the other hand there are very little experimental data where they are tested on actual flight hardware because of risk mitigation for commercial satellites and due to the high cost of launching pure experimental satellites. In this paper we propose a new Cube-Sat concept where the satellite is ascended using an ordinary weather balloon up to about 20 km altitude and then dropped. The attitude control system is then tested during the free-fall period of about five minutes where on board data is continuously transmitted to a nearby receiving station. The design is based on the requirement that the system shall be reusable. Thus it is equipped with a parachute and small balloons for buoyancy, and a GPS providing data to help locate the hardware after touchdown. As the weather balloons only cost some tens of dollars the presented system will provide a cheap and effective platform for excessive testing of advanced attitude control laws.