Mission and system design of a 3U CubeSat for passive GTO to LEO transfer

This paper denotes a mission concept and system design for a 3U CubeSat technology demonstration. The spacecraft carries an inflatable, ejectable balloon that is used to engineer its area-to-mass-ratio. In this way, the effects of aerodynamic drag and solar radiation pressure on the orbit evolution can be exploited in order to passively transfer from a geostationary transfer orbit (GTO) to a low Earth orbit (LEO). This is of importance since with the increasing interest in CubeSat missions, demand for piggy-back launches to LEO is exceeding availability. In order to tap into the many GTO launches an appropriate strategy is therefore needed to transfer CubeSats from the release orbit into a LEO orbit. The strategy proposed here exploits the effects of atmospheric drag and solar radiation pressure to passively decrease the apogee altitude and increase the perigee altitude respectively. This is achieved by deploying a light-weight balloon that increases the area-to-mass-ratio of the spacecraft. After deployment and rigidisation the manoeuvre occurs completely passively, allowing a power down of the spacecraft's electronics for the transfer duration to avoid radiation damage from the Van Allen belts. Once the goal orbit is reached the spacecraft can be powered up again and the balloon is ejected to avoid rapid deorbiting. It is shown that the abandoned balloon is removed from orbit within weeks. The paper contains mission design and scenario selection and the system design of the orbital transfer module