.The growing interest in CubeSat swarm and constellation systems by NASA, the Department of Defense and commercial ventures has created a need for self-managed inter-satellite networks capable of handling large amount of data while simultaneously precisely synchronizing time and measuring the distances between the spacecraft. CrossTrac Engineering, Inc., in cooperation with our partners Professor Kerri Cahoy of the Massachusetts Institute of Technology and Mr. Paul Graven of Cateni, Inc., proposes to develop a free space optical communications and ranging system with inherent precision pointing as a 1U module for 3U and larger CubeSats requiring intersatellite crosslinks. Based on technology developed by Professor Cahoy and her team at MIT, the module will enable small satellites to achieve the sub-milliradian pointing control of the optical beam necessary to close laser crosslinks at ranges from 200 km to 1000 km with input power of less than 20 W and data rates of 100 Mbps and greater, all within a 10 cm x 10 cm x 10 cm (1U) volume or smaller. The proposed work is directly aligned with the STTR solicitation T11.02 and the objectives of Technology Area 5.1 Optical Communications and Navigation in the NASA 2015 Technology Roadmap. Optical crosslinks are a key technology that will enable new multi-spacecraft CubeSat and microsatellite missions. These missions include large constellations for global data distribution and rapid response Earth imaging and asset tracking as well as swarm missions that, among other tasks, can be formed into sparse aperture systems providing unprecedented image resolution. These swarm missions require precise relative position knowledge as well. The optical terminal being developed under this effort will provide this sub-mm level relative position knowledge. Furthermore, the free space optical crosslinks can be used to make atmospheric composition and thermophysical measurements (e.g., via laser occultation).
.The optical communications terminal and networking concept developed under this effort will provide new capabilities to small spacecraft operating in constellations and swarms, allowing them to transfer large amounts of data around the network while simultaneously synchronizing time across the swarm and measuring the positions of the spacecraft relative to one another. This development will support NASA constellation and swarm missions, providing a high data rate network and precision metrology system. Swarms of spacecraft, relying on the close coordination of action to perform a mission in unison that cannot be performed by a single spacecraft, can use this technology to explore Earth-Sun interaction by measuring spatial variations in electromagnetic fields; create bistatic and multistatic radar systems; and create large area sparse aperture imagers with unprecedented resolution, among other applications. These swarm missions can be performed in environments from low Earth orbit to geosynchronous orbit as well around the moon other planetary bodies, near-Earth objects and comets comets.
In many ways, commercial ventures have led the way in the development of capable CubeSat platforms and the exploitation of their capabilities to meet customer needs. The optical terminal and related network will enhance the capabilities of existing imaging and asset tracking CubeSat constellations by providing a means to move large amounts of data through the constellation quickly, reducing data transfer latency and making more efficient use of ground stations. Proposed constellations that intend to provide data services to customers throughout the world even in remote locations will require crosslinks to provide immediate connections between users and distributed ground stations. Optical crosslinks will be necessary for these users to move the large amounts of data they produce. Swarms of spacecraft, relying on the close coordination of action to perform a mission in unison that cannot be performed by a single spacecraft, can use this technology to create large sparse aperture imaging systems with unprecedented resolution, among other applications. Similar missions are being explored by the Department of Defense and the National Reconnaissance Office..