Temperature sensors for satellites
doi:10.1038/nindia.2012.103 Published online 17 July 2012
Researchers have devised a new technique for measuring the temperature of solar-cell blankets in Earth-bound artificial satellites. This technique will be useful because the temperature of a solar-cell blanket is an important parameter that must be measured accurately throughout a satellite's mission.
All Earth-bound artificial satellites use solar cells to generate electrical power. However, when satellites are eclipsed from the Sun, solar power is not available. In addition, there is a large temperature shift between when the satellite faces the Sun's radiation and when it is eclipsed.
This shift induces stress on the metallic interconnects in the solar cells, which can cause the solar array to fail. The temperature of a solar-cell blanket therefore requires constant monitoring. Present techniques measure the solar panel temperature — not the solar-cell blanket temperature.
To find an effective technique for measuring the solar-cell blanket temperature, the researchers investigaed three space-grade solar cells: a silicon solar cell, a gallium arsenide cell and a multijunction cell. They placed the cells in a cryobox with temperature ranging between −180°C and 80°C.
They measured the sensitivity of each solar cell by observing how its capacitance changed with temperature. The gallium arsenide cell had the highest capacitance per unit area, but the multijunction cell was the most sensitive. The capacitance of the gallium arsenide and multi-junction cells varied nearly linear with temperature.
The researchers say that the sensitivity of solar cell capacitance is comparable to other sensors, with the added advantage of measuring solar-cell blanket temperature rather than solar panel temperature.
The authors of this work are from: ISRO Satellite Centre, and BNM Institute of Technology, Bangalore, India.
Krishna, H. A. et al. Use of solar cells for measuring temperature of solar cell blanket in spacecrafts. Sol. Energ. Mat. Sol. C 102, 184-188 (2012) | Article |