* Astronomy

Running on empty

When you consider the cost of launching a satellite, it's small wonder that ESA is looking to keep them working as long as possible. For satellites offering communications services that are bought and paid for, this extended life is critical. Now there is a solution.
Communication satellites are often placed in the unique 'geostationary orbit', almost 36 000 km above the equator where their speed matches Earth's 24-hour spin.
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