RadioSTAR (Radio Spacecraft for Telecommunications Assessment and Risk-reduction): A 3U CubeSat for validation of ground stations and link budgets

Abstract

As the number of small satellites in orbit increases, an increasing number of ground stations must be constructed, recommissioned, or updated in order to provide uplink and downlink access. However, prior to deployment of a spacecraft, it is difficult to evaluate a ground station’s performance capabilities. Over-the-air testing with the spacecraft, prior to launch, may not be possible for remotely located ground stations, or stations in environmentally challenging locations due to humidity or season. In the event that a spacecraft is deployed, and the ground station has a flaw, the critical first days on-orbit may be spent debugging ground station hardware, leaving the spacecraft uncontacted and in an unknown state. In the event that a spacecraft has an unusually short lifetime, such as a low-orbiting CubeSat or a mission with limited fuel or power, a non-functional ground station could make the difference between getting little data and getting no data at all. This paper proposes a spacecraft with a versatile software-defined radio onboard, which can simulate nearly any upcoming spacecraft’s radio system, thus qualifying a ground station’s readiness for on-orbit operations. Furthermore, this spacecraft can be used for refining the link budget design, eliminating uncertainties like proper values to use for system noise temperature. Additional applications for such a spacecraft will be explored, including acting as a known signal source for calibration of radio astronomy installations. This paper acts as a first look at the feasibility of a RF calibration and validation spacecraft.