Optical intersatellite links

Direct communication links between spacecraft will be an important element in the future space communication infrastructure. Optical intersatellite links (OISLs) offer the major advantages over conventional microwave links of low mass, power consumption, size and real estate, and flight-qualified transceivers are now feasible. There are, however, formidable problems in achieving pointing accuracy and stability of the order of a few millionths of a degree. The Japanese ETS VI experiment, the European Space Agency´s `SILEX´ experiment and NASA´s laser communications transceiver are due to fly in the mid-1990s. The authors discuss the status of OISL systems and technology and describe the British Aerospace optical multiple access (OMA) system as an example of a lightweight transceiver attractive to spacecraft designers