Space Station Laser Communication Transceiver

NASA/Goddard Space Flight Center (GSFC) has initiated the development of experimental optical communication system which will be installed on Space Station Freedom. This system is part of the Space Station Attached a Payloads Program and is currently scheduled for a 1997 launch. The system is being designed to carry out comprehensive set of tests to evaluate and demonstrate the capabilities of this relatively new technology. Communication tests at rates up to 1200 mbps will be conducted over the space-to-ground link using an existing tracking facility at the GSFC. GaAlAs semiconductor lasers will be intensity modulated using 4 slot pulse position modulation format. Direct detection receivers using silicon avalanche photodiodes will be utilized, and 1 microradian accuracy pointing will be achieved with 2 cascaded pointing stages. Successful completion of this in-orbit test program should demonstrate both the technical maturity and readiness of this technology for follow-up operational missions.