Stabilizing an S-band antenna for mobile communication from the moon

The Google Lunar X-prize is a race for the first commercial program to fly a rover to the Moon and return imagery. In order to meet media expectations and generate significant revenue, this imagery must be in 720 p high definition format, which necessitates very high bandwidth communications. In order to provide such bandwidth throughout the mission, a high gain antenna must remain pointed at Earth, even while roving. This paper describes the simulation and performance analysis of a system to stabilize an S-band antenna for a moving X-prize class rover. To determine the necessary flight components and control system complexity, various sensor configurations are compared. These sensors include an Earth tracking camera, an inertial measurement unit and motor encoders. The resulting system demonstrates the pointing capability necessary to achieve a sustained 2.0 Mbps data transfer to a 13 m ground receiving dish, enough for a successful commercial venture to the Moon.