How is a Satellite Controlled From the Earth?
Radio signals are sent to the satellite using large radio dishes which are pointed to the satellite's location in space. The large quantity of information sent from the satellite to the ground is also transmitted by high frequency radio waves.
What Will Happen to Gaia After it Stops Functioning?
After Gaia comes to the end of its 'lifetime', it will be left to orbit freely. As its orbit is far from Earth and from other more crowded areas of space, it won't affect other satellites. Only an impact by a meteorite or a comet will destroy the 'dead' satellite.
How Many Stars Will Gaia Measure?
Gaia will measure more than one billion stars. This constitutes about 1 per cent of the total star content in the Milky Way.
What Other Objects Will Gaia Observe?
Gaia will also observe more around 100 000 objects in our solar system (mostly asteroids), around 10 000 new extrasolar planets, more than 50 000 brown dwarfs (stars of very low mass that do not emit much light because no nucleosynthesis takes place in their interior), about 20 000 supernovae (stars exploding at the end of their lives), and a large number of galaxies.
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