Previous Year Question
What is the source of electrical energy in an artificial satellite?
Thermopile
Solar cells
Dynamo
Small nuclear reactor
Correct Answer: B
Detailed Solution
Conventional artificial satellites use Solar Arrays to obtain electrical energy. These arrays contain a large number of Photovoltaic Solar Cells, which directly convert sunlight into electrical energy.
When the satellite is illuminated by the Sun, the solar cells supply power to its communication systems, sensors, onboard computers and other electronic equipment. At the same time, rechargeable batteries are charged.
When the satellite enters the Earth's shadow during an eclipse period and sunlight is unavailable to the solar panels, batteries provide the stored electrical energy.
For example, ISRO's GSAT-9 has two solar arrays containing Ultra Triple Junction solar cells that generate about 3500 W of electrical power. Similarly, the solar arrays of IRNSS-1F generate about 1660 W of electrical power.
A Dynamo requires mechanical rotation and is therefore not the normal primary power source of a satellite. A Thermopile is also not the usual primary satellite power source. Nuclear-based power sources may be used in some specialised space missions.