The Lunar Laser Communications Demonstration (LLCD)

Abstract

NASA is presently overseeing a project tocreate the world’s first free-space lasercommunications system that can be operated overa range ten times larger than the near-earth rangesthat have been demonstrated to date. To be flownon the Lunar Atmosphere and Dust EnvironmentExplorer (LADEE), which is planned for launch byNASA in 2012, it will demonstrate high-rate lasercommunications from Lunar orbit to atransportable ground terminal on the Earth. Tosupport up to 622 Mbps over the approximately400 thousand kilometer link, the system will makeuse of a high peak-power doped-fiber transmitter,a hybrid pointing and tracking system, highefficiency modulation and coding techniques,superconducting photon-counting detectors, and ascalable optical collector architecture. It also willsupport up to 20 Mbps on the optical uplink, plus ahighly accurate continuous two-way time-of-flightmeasurement capability with the potential toperform ranging with sub-centimeter accuracy tothe moving spacecraft. The project is beingundertaken by MIT Lincoln Laboratory (MIT/LL)and the NASA Goddard Space Flight Center(GSFC.)