The Heat Is On… And ESA’s Gaia Survives!
Do you remember Gaia? It’s ESA’s space-born mission to take on a census of a thousand million stars in our galaxy. That’s a pretty big number but we’re used to that.
It will check out each of its target stars seventy times over a five-year period – charting their positions, distances, movements and changes in magnitude. If all goes well, it should reveal hundreds of thousands of new discoveries, like extra-solar planets and brown dwarf stars. In our solar system alone, Gaia is expected to uncovered hundreds of thousands of asteroids. However, none of this can happen unless the plucky little spacecraft is able to survive the harshness of space.
Now ESA’s Gaia mission, slated to launch in 2013, has passed an extreme test – one to prove it can withstand extreme temperatures. Once Gaia settles into orbit some 1.5 million km from Earth, it will operate at a temperature of –110°C . It will be permanently shielded from the heat of the Sun by a giant “umbrella” attached to the spacecraft body. This shade will keep its instruments cool and one of the most vital is the service module. Here is where the “brains” of Gaia are housed, instruments such as thermal control, propulsion, communication, and attitude and orbit control.
The tests were carried out in a barrel-shaped chamber under vacuum conditions. During the 19-day test at Intespace, a spacecraft test facility in Toulouse, Gaia was tortured under a wide range of temperatures. During the thermal balance test, the service module units were turned on and monitored for their response to extreme cold – a –170°C environment. What’s more a thermal-vacuum cycle test was performed where the units met their match as heaters were aimed their way. These functional tests – where temperatures between –20°C and +70°C were recorded inside Gaia during the test period – proved the instruments performance.
“The thermal tests went very well; all measurements were close to predictions and the spacecraft proved to be robust with stable behaviour,” reports Gaia Project Manager Giuseppe Sarri.
Before the end of this year, Gaia will go under the gun again for two months as the same thermal tests will be carried out on the payload module, which contains the scientific instruments. Once proven, the two modules will then be joined together around the beginning of 2013.
“The latest thermal test marks a major milestone achieved in the development of Gaia,” says Giuseppe. “It demonstrated that the service module is compatible with working in space and that we are on track for launch by the end of next year.”
Original Story Source: ESA News Release.
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