Optical-to-Orion (O2O) Ground Terminal (GT) at Table Mountain Facility (TMF)

NASA is planning a bi-directional space-to-ground optical-communications detailed test objective (DTO), from the crewed Orion spacecraft scheduled to fly on Artemis II. A space terminal element (STE) developed by MIT Lincoln Laboratory, and NASA Goddard Space Flight Center (GSFC) is planned for flight on-board the Orion spacecraft. NASA GSFC will implement an Optical-to-Orion ground segment (O2O GS). One of the ground terminals (GT) servicing the O2O GS is planned at the Optical Communications Telescope Laboratory (OCTL) located at the Table Mountain Facility, near Wrightwood, CA, while the other GT will be co-located with the O2O GS at the White Sands Complex (WSC), New Mexico. A functional description and development status of O2OGT TMF is described in this paper. The so called O2OGT TMF is designed to support high photon efficiency (HPE) uplink and downlink signaling. The instrumentation of the O2OGT TMF will include (i) an optical assembly (OA) for optically interfacing laser signals to and from the OCTL telescope (ii) a beacon laser assembly (BLA) for transmitting modulated beacon lasers; (iii) an uplink laser assembly (ULA) for transmitting 10-20 Mb/s data to the STE (iv) a superconducting nanowire single photon detector (SNSPD) array for detecting the communications downlink (v) a ground signal processing assembly (GSPA) for processing the detected signal and extracting downlinked information codewords, as well as, measuring time of flight range and range rate (vi) a monitor and control (M&C) assembly for gathering and exchanging GT telemetry and (vii) a user gateway (UG) computer for interfacing user data to and from the O2O GS. Existing atmospheric channel monitor (ACM) will be used. The downlink will be received at discrete data-rates between 20 Mb/s and 260 Mb/s.