Investigating new Service System Solutions for High Altitude Balloons : Feasibility Study and Design Challenges
Abstract: The high altitude balloon operations at Esrange Space Center have been goingon since 1972, and about 550 launches have been performed. Their present service system for the high altitude balloons is about 18 years old. To be able to meet the requests from their customers, SSC have started the development of a new service system. A service system contains all features and technology required to perform a high altitude balloon mission. This system is separated from the payload. Important design aspects for the new service system have been investigated to be able to leave recommendations to SSC. These are frequency for the radio communication, modulation scheme for the communication link, prevention of corona discharge, and available computer systems to be used as on-board computers. These design aspects have been evaluated according to the requirements for the development project. Theory, articles, available standards and analyzes have been read and evaluated to reach a conclusion about these subjects. It was found that the best frequency bands are the 400MHz-band, downlink, and the 450MHz-band, uplink. The operation in these bands will be unmodified for many years, and the link suffers little loss. The 2.3GHz-band is interesting from an international perspective, and it is suggested that SSC work to get a band dedicated to aeronautical services in this band. The best modulation scheme for the service system is GMSK, as it has very good spectral eficiency. The corona discharge can only be prevented indirect by SSC, as the phenomena occurs within or between components, aspects which SSC can't control. Standardized methods for tests and specications lists was suggested to minimize the risk of a discharge. The best computer system is an in-house designed service system that have been used on sounding rockets. It fits the present requirements the best. It suggested that the Beaglebone Black should be implemented in basic systems, providing processing and storage via simple serial communication, as it is a very cost eficient solution.
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