It seems Aussie cows can stop looking anxiously skywards from now on.When satellites reach the end of their lives, they are often destroyed through re-entry into the Earth's atmosphere.
Larger satellites don't always burn up entirely, however. This is because well-shielded components and parts made of materials capable of withstanding high temperatures, like titanium, can make it through the atmosphere and cause damage when they hit the ground. When the US space station Skylab was deorbited in 1979, for example, it killed a cow in Australia.
The flywheels used for attitude control on a spacecraft are a particular problem. They are usually made from titanium and are well shielded inside the spacecraft. Now NASA has redesigned the flywheel using an aluminium alloy with a lower melting point than titanium and placed it in a housing that is designed to burn up easily on re-entry.
Link & Image: New Scientist
Tags: Disposable | Satellites
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