Communications support for lunar missions using the TDRS II system

Abstract The United States National Aeronautics and Space Administration's (NASA's) Office of Exploration (OEXP) is evaluating potential scenarios for robotic and piloted missions to the Moon. This work is part of the OEXP effort to establish a human exploration program during the next century. For more than 4 years, NASA's Goddard Space Flight Center (GSFC) has been performing systems engineering analysis for lunar exploration scenarios. The GSFC studies have focused primarily on lunar communications, data systems, and operations. Two basic Earth-region communications architectures have been identified and seriously considered: ground terminal architectures, such as the Deep Space Network, and geosynchronous relay satellite architectures, such as the Tracking and Data Relay Satellite II (TDRS II). The TDRS II, as currently specified, is a viable architecture and low-cost option - at least for early (1998 - 2005) lunar mission phases. Development of TDRS II, designed as a follow-on to the currently operating Tracking and Data Relay Satellite System (TDRSS), is scheduled to begin soon. A major benefit of the TDRS II option is that the system as planned can provide substantial support to early lunar missions without modification.