Development, test and flight results of the RF systems for the YES2 Tether Experiment
- Paper number
IAC-08.E2.3.6
- Author
Ms. Guillermina Castillejo Cucarella, Technical University of Valencia, Spain
- Coauthor
Mr. Maurizio Burla, Italy
- Coauthor
Mr. Andrzej Cichocki, University of Warsaw, Poland
- Year
2008
- Abstract
This paper highlights design, realization, testing and flight results of the Radio Frequency developments (RF) for ESA's second Young Engineers’ Satellite (YES2), with particular attention to its inter-satellite UHF link. The YES2 piggybacked on the Russian-built Foton microgravity platform in September 2007 with as objective the controlled deployment of a 32 km tether, in order to release a small re-entry capsule. That mission was successfully performed, although the capsule could not (yet) be retrieved. This complex project was performed by hundreds of students from all over Europe. One of the student teams was concerned with the development of RF systems. Most significant is the inter-satellite link between the tethered subsatellite and the tether deployer, through which tether science data from the subsatellite (e.g. tensiometer and dynamic sensors) can be recovered. Furthermore, a GPS/GLONASS receiver was placed on both ends of the tether to monitor the tether deployment. Next, the re-entry capsule has its own transmitter which sends data to an especially developed mobile ground station. Finally, recovery of the landed capsule was planned using an ARGOS beacon, for which two DDRR (loop antennas) were designed that transmit the beacon signal to the ARGOS constellation for positioning. This paper provides a brief overview of these systems and tests performed, then focusses on innovation, specifically the UHF inter-satellite link, and concludes with a discussion of flight results and applicability of the systems to other low-cost satellites, balloon experiments or sounding rockets. The inter-satellite link functions on the 437 MHz amateur band using the low-cost integrated transceivers Chipcon CC1010 and CC1070. The transceivers showed good impedance matching with antennas. Power output and non-linear distortion for the transmitter have been evaluated. A transparent serial protocol was implemented, allowing tether science data to be relayed between the spacecraft with little complexity for the on-board computers on either end. The antennas represented an innovation. Driving requirement was to have no protruding elements and little effect on satellite dimensions. The transmitting antenna is a modified version of a commercial folded monopole-like layout. A common patch antenna design was discarded for dimensional issues due to the low operating frequency. By testing, the antenna was tuned in order to get the desired performance when mounted on the satellite. The receiving antenna is a hexagon-shaped dual feed circularly-polarized loop. This innovative shape has been chosen to obtain an antenna element that is conformal with the satellite body. It was tested in an anechoic chamber as a scale model and in open air as a 1:1 model. Tests were carried out to determine the best feeding technique. Beyond such design and performance tests, all the RF flight model subsystems went through a system test campaign for full qualification, including electromagnetic compatibility, thermal vacuum and shaker testing. Although in the final stages of integration a number of compromises were made that reduced the flight performance, some high quality mission data was obtained and a number of systems can be recommended for future use.
- Abstract document
- Manuscript document
IAC-08.E2.3.6.pdf (🔒 authorized access only).
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