Deployable Optical Receiver Array Cubesat

Small satellites and cubesats often have low data transmission rates due to the use of low-gain radio links in UHF and S bands. These links typically provide up to only 1 Mbps for communication between the ground and LEO, limiting the applications and mission operations of small satellites. Optical communication technology can enable much higher data rates and is rapidly gaining hold for larger satellites, including for crosslinks within SpaceX’s Starlink constellation and upcoming NASA deep space missions. However, it has been difficult to implement on small satellites and cubesats due to the need for precision pointing on the order of arcseconds to align the narrow optical laser beam between terminals--a laser transmitter in LEO may yield a footprint less than 100 meters wide at its receiving ground station. We report the development of a 3U cubesat to demonstrate new optical communication technology that eliminates precision pointing accuracy requirements on the host spacecraft. The deployable optical receiver aperture (DORA) aims to demonstrate 1 Gbps data rates over distances of thousands of kilometers. DORA requires an easily accommodated host pointing accuracy of only 10 degrees with minimal stability, allowing the primary mission to continue without reorienting to communicate and/or enabling small satellite missions using low-cost off-the-shelf ADCS systems. To achieve this performance, DORA replaces the traditional receiving telescope on the spacecraft with a collection of wide-angle photodiodes that can identify the angle of arrival for incoming communication lasers and steer the onboard transmitting laser in the corresponding direction. This work is motivated by NASA’s plans for a lunar communications and navigation network and supported by NASA’s Space Technology Program (STP). It is ideally suited for crosslink communications among small spacecraft, especially for those forming a swarm and/or a constellation, and for surface to orbit communications. We will implement the deployable optical receiver aperture and miniature transmission telescope as a 1U payload in the 3U cubesat and conduct the demonstration flight in LEO. Future implementations of the DORA technology are expected to further enable omnidirectional receiving of multiple optical communications simultaneously and accommodate multiple transmitting modules on a single cubesat