The economic advantages of data relay satellites

It is shown that a Data Relay Satellite (DRS) system can improve the return on investments in low-earth-orbiting communications satellites by increasing the real-time communications capability with the ground per orbit. Positioning of a DRS in synchronous geostationary orbit allows a coverage of up to 70 percent of the total orbit trajectory for a satellite at 1000 km. Studies performed by ESA over the past two years have pointed to the conclusion that a two-satellite system orbited at 50 deg W and 65 deg E, respectively, would provide adequate coverage for the entire European DRS mission requirement. Design configurations for a European DRS system are described. The frequency plan for a DRS system in LEO is given in an appendix.