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What are the possible sources of energy for a rover robot like ‘Curiosity’?

The Curiosity rover uses heat from the radioactive decay of plutonium to generate its energy.

However, several spacecraft have used solar energy, an important form of renewable energy.

What is solar energy?
energy from the Sun
Why is solar energy described as ‘renewable’?
because solar energy is constantly ‘renewed’, and always available so long as the Sun is shining, so we won’t run out of this type of energy.

One example of spacecraft that used solar energy is Rosetta, which was launched by the European Space Agency (ESA) in 2004 to investigate the structure of a comet. A ‘lander module’ called ‘Philae’ was set onto the surface of the comet to find out what it was like, and this also used solar energy (this was not a ‘rover’ because it was designed to stay still).

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What is a comet?

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DLR German Aerospace Center

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Story of Rosetta

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The Rosetta spacecraft used an array of solar cells to capture the energy of the sun and convert it to usable energy.

What is a solar (or photovoltaic) cell?

Solar cells are thin, plate-like structures which are able to capture the energy of the sun. They come in a range of sizes, and are usually made of silicon

Can you name any items that may contain solar cells?
digital watch; electronic calculator; roof panels
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As you can see in the picture, solar cells are now commonly set up in fields in large numbers, and they can also be found on the roofs of houses.

What sort of energy conversion takes place inside a solar (photovoltaic) cell?
light energy to electrical energy

Note that there are different sorts of solar ‘panels’ on roofs and elsewhere. Some consist of solar cells, but others are panels containing water which is heated up by the Sun.

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Find out more about solar cells at:

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Hopefully, solar energy will help you and the devices you might use as you start to explore Mars. But we can’t always rely on solar energy: during the Rosetta mission, Philae landed oddly on the comet it was meant to study. Scientists believe that it landed in a shaded part of the comet with very little sunlight.

Would a solar (or photovoltaic) cell be effective if it is constantly in shade?
No: the less light energy available to a solar cell, the less electrical energy it can produce.

Unfortunately, Philae was not able to use solar power, and it lost contact with Rosetta when its batteries ran out after two days. Though it carried out some tests on the comet surface, it was unable to carry out most planned activities.