USB Command Link via TDRSS to Satellites and Possibly Space Launch Vehicles

Abstract

In the wake of the modernization of the Tracking and Data Relay Satellite System (TDRSS), NASA recently upgraded its remaining ground tracking stations, and replaced its Tracking and Data Relay Satellites (TDRSs) with more advanced satellites (TDRSS-II). This paper shows that the new satellites can be used as relay platforms for commanding future space vehicles, including satellites and launch vehicles, in the Unified S-Band (USB) with adequate link margins. The TDRS service as a relay platform, can be extended to support other satellite TT&C services such as state of health telemetry and tracking. In this paper, USB command link scenarios are presented for four types of space vehicles to support this claim: a geosynchronous Earth orbit (GEO) satellite, a medium Earth orbit (MEO) satellite, a low Earth orbit (LEO) satellite, and a flight termination system of a launch vehicle. Command link margins in excess of 3 dB are achieved in all the scenarios using TDRSs as relay satellites.