The Lunar Laser Communications Demonstration (LLCD)

TLDR

NASA is developing the first free‑space laser communications system capable of operating over a range ten times larger than previously demonstrated near‑Earth links. The system will be flown on the LADEE mission to demonstrate high‑rate laser communications from lunar orbit to a transportable ground terminal on Earth. The design supports up to 622 Mbps over the ~400 000 km lunar‑Earth link using a high‑peak‑power doped‑fiber transmitter, hybrid pointing and tracking, efficient modulation and coding, superconducting photon‑counting detectors, and a scalable optical collector, while also providing a 20 Mbps uplink, continuous two‑way time‑of‑flight measurement, and sub‑centimeter ranging, and is being built by MIT Lincoln Laboratory and NASA Goddard Space Flight Center.

Abstract

NASA is presently overseeing a project to create the world's first free-space laser communications system that can be operated over a range ten times larger than the near-earth ranges that have been demonstrated to date. To be flown on the lunar atmosphere and dust environment explorer (LADEE), which is planned for launch by NASA in 2012, it will demonstrate high-rate laser communications from lunar orbit to a transportable ground terminal on the Earth. To support up to 622 Mbps over the approximately 400 thousand kilometer link, the system will make use of a high peak power doped fiber transmitter, a hybrid pointing and tracking system, high efficiency modulation and coding techniques, superconducting photon counting detectors, and a scalable optical collector architecture. It also will support up to 20 Mbps on the optical uplink, plus a highly accurate continuous two-way time of flight measurement capability with the potential to perform ranging with sub-centimeter accuracy to the moving spacecraft. The project is being undertaken by MIT Lincoln Laboratory (MIT/LL) and the NASA Goddard Space Flight Center (GSFC.).