Abstract Effective space situational awareness/battlespace awareness (SSA/BA) requires determination of resident space object (RSO) characteristics. Responsive SSA can often be enhanced with the use of small inspector satellites due to their relative ease to integrate and launch, coupled with their low cost. However, small satellites are often constrained by their inherent limits on power, mass, volume, $\text{Δ}$V, and processor capabilities. Inspection missions are further complicated when the RSO is un/noncooperative (nRSO). In such cases, the inspector must execute its mission without the benefit of GPS data from the nRSO, beacons/reflectors on the nRSO, or any a priori information about the nRSO. Radar and LiDAR systems can be effective, but often require excessive power and volume for use on a small satellite. Furthermore, in uncooperative scenarios, detection of the inspector spacecraft by the RSO may be undesirable. The Missouri University of Science and Technology's Satellite Research team (M-SAT) has been developing a technology demonstration mission that uses two cameras configured as a stereoscopic imager sensor that can provide the relative state of an nRSO in near real-time. The mission is composed of two microsatellites: MR SAT as the inspector and MRS SAT as the nRSO. The mission goal is to demonstrate that the stereoscopic imager can be used for both autonomous proximity operations as well as providing images that can used to determine characteristics of an nRSO including rendering a three-dimensional reconstruction of the nRSO.

Highlights • A microsatellite pair developed to perform an autonomous nRSO inspection missions. • Stereoscopic imager developed to estimate relative position and velocity of nRSO. • Inspector satellite uses a custom R-134a propulsion system to enable 6 DOF control. • A hybrid software architecture links GNC software with overarching state machine.