In orbit performance of the UNISAT-3 solar arrays
- Paper number
IAC-06-C3.4.-D3.4.04
- Author
Prof. Fabio Santoni, University of Rome "La Sapienza", Italy
- Coauthor
Dr. Fabrizio Piergentili, University of Bologna, Italy
- Coauthor
Prof. Filippo Graziani, University of Rome "La Sapienza", Italy
- Year
2006
- Abstract
The UNISAT program was established in early nineties at University of Rome with the aim to design, realize and launch in orbit didactical microsatellites. Applied research and student education are main UNISAT program goals. The research is devoted to testing in orbit and space qualifying terrestrial commercial off the shelf (COTS) and industrial components and technologies, yielding a direct technological interest for industries. This allows to keep program cost low and affordable for University. In the framework of UNISAT program three microsatellite have already been successfully launched and the fourth satellite is scheduled to be launched on May 2006. UNISAT-3 is the third microsatellite designed and manufactured by a team of students, researchers and professors at the Scuola di Ingegneria Aerospaziale of the Università di Roma “La Sapienza”. It was successfully launched on 29th June 2004, from the Baikonour cosmodrome using the DNEPR launch vehicle. The previous two satellites, UNISAT and UNISAT-2, have been launched on September 2000 and on December 2002 by the same launch vehicle. Designing solar arrays for university low-cost microsatellites is extremely critical since the available surfaces are small, attitude control is not very accurate, the solar panel working condition is very sensitive to solar panel illumination (sun angle) and temperature. Moreover terrestrial solar cells suffer degradation due to aggressive space environment. Different commercial off-the-shelf technological solutions have been exploited to provide power on board UNISAT microsatellites. This paper deals with UNISAT-3 microsatellites photovoltaic subsystem, chosen solutions are deeply discussed and on orbit results depicted. A comparison among different technological solutions implemented is considered as the basis for the future development on UNISAT-4 power system. UNISAT-3 photovoltaic system was realized with different kind of solar cells exploiting different technologies with the aim to verify their on-orbit behavior. Some UNISAT-3 solar array was realized using silicon monochristalline terrestrial grade solar cells glued to the panel with an enhanced method in order to make them withstand launch and space environment loads. Other arrays were manufactured with mono-crystalline silicon high efficiency space qualified solar cells and multi-junction solar cells. The performances of terrestrial grade silicon solar cells will be presented showing the possibility of their use in space projects. The efficiency decreasing of triple junction low-cost solar cells will be also depicted. Data collected on the on-orbit tested solar cells are depicted and discussed.
- Abstract document
- Manuscript document
IAC-06-C3.4.-D3.4.04.pdf (🔒 authorized access only).
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