A New TDRSS Compatible Transceiver for Long Duration High Altitude Scientific Balloon Missions

Abstract

High altitude scientific balloons have been used for many years to provide scientists with access to space at a fraction of the cost of satellite based experiments. In recent years, these balloons have been successfully used for long duration missions of up to several weeks. Longer missions with durations of up to 100 days (Ultra-Long) are on the drawing board. An enabling technology for the growth of the scientific balloon missions is the use of the NASA Tracking and Data Relay Satellite System (TDRSS) for telemetering the health, status, position and payload science data to mission operations personnel. The TDRSS system provides global coverage by relaying the data through geostationary relay satellites to a single ground station in White Sands New Mexico. Data passes from the White Sands station to the user via commercial telecommunications services including the Internet. A forward command link can also be established to the balloon for real-time command and control. Early TDRSS communications equipment used by the National Scientific Balloon Facility was either unreliable or too expensive. The equipment must be able to endure the rigors of space flight including radiation exposure, high temperature extremes and the shock of landing and recovery. Since a payload may occasionally be lost, the cost of the TDRSS communications gear is a limiting factor in the number of missions that can be supported. Under sponsorship of the NSBF, General Dynamics Decision Systems has developed a new TDRSS compatible transceiver that reduces the size, weight and cost to approximately one half that of the prior generation of hardware. This paper describes the long and ultra-long balloon missions and the role that TDRSS communications plays in mission success. The new transceiver design is described, along with its interfaces, performance characteristics, qualification and production status. The transceiver can also be used in other space, avionics or terrestrial applications.