Increasing the information capacity of the Deep Space Network, a global network of radio frequency receivers used to communicate with and track interplanetary spacecraft, will increase the number and complexity of future space explorations missions it can support. Adding optical communications capability will improve the information capacity of the Deep Space Network. The availability of an optical communication link between a deep space transmitter and an Earth-based receiver is limited by the location of the sun relative to the line of sight. The sun could block the line of sight entirely, account for sufficient background radiation to degrade the system performance, or, the receiver telescope may form an image of the sun resulting in a safety hazard. The large diameter ground telescopes capable of supporting high rate optical links over solar-system distances exacerbate these challenges. We present experimental results bounding the safety threshold for solar-induced damage upon a Deep Space Network antenna and predict system level performance.
We are developing an inter-satellite omnidirectional optical communicator (ISOC) that will enable gigabit per second data rates over distances up to 1000 km in free space. Key features of the ISOC include its high data rates and its ability to maintain multiple simultaneous links with other spacecraft. In this paper we present design considerations for the ISOC, including selection of the mission-appropriate geometry, telescope design, receiver design, as well as beam pointing considerations. We also present experimental results obtained with the ISOC prototype. In addition, we present design considerations for a low-Earth-Orbit mission where four ISOC-furnished CubeSats form a swarm suitable for remote sensing. We believe the ISOC could be a technology enabler for future constellation and formation flying CubeSat missions for Remote Sensing.