Jan 22, 2014 |
Rosetta's eyes
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(Nanowerk News) The ten-year journey of the Rosetta space probe, which will end this year in August when it arrives at the Churyumov-Gerasimenko comet, was packed with interesting points of interest. In order to increase its speed, Rosetta flew past Earth three times and Mars once; the asteroids Steins and Lutetia also crossed the probe’s path. And each time the OSIRIS camera system provided impressive images. The development and construction of the eye was headed by a team of scientists from the Max Planck Institute for Solar System Research.
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Whereas Earth and Mars primarily offered the experts the opportunity to test and calibrate their instrument on a comparably close object, the asteroids were of major scientific interest. Since the Rosetta fly-by in July 2010, the Lutetia asteroid numbers among the best-investigated small bodies - and has proven to be a true primeval rock. Owing to its surface structure, the Max Planck researchers estimate it to be at least 3.6 billion years old.
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Small planet: Thanks to Rosetta’s rendezvous with the Lutetia asteroid in July 2010, this celestial body is accurately charted today. (Image: ESA 2010 / MPS for OSIRIS-Team MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA)
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OSIRIS’ distinctive aspect: The camera system consists of a telephoto and a wide-angle camera. The instrument can thus view the comet with a dual approach when it arrives at its destination: while the telephoto camera can resolve structures measuring a mere two centimetres on the surface of Churyumov-Gerasimenko from a distance of one kilometre, the wide-angle camera keeps the whole celestial object in view.
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The cameras are additionally equipped with a total of 25 colour filters. This allows them to investigate the light which Churyumov-Gerasimenko reflects into space in specific wavelength ranges and tease out information on the mineral composition of the surface or the gas streaming from the comet.
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However, as recent years have shown, OSIRIS is not only suitable for research objects in the immediate vicinity. In 2005, for example, when NASA’s Deep Impact probe caused an object with a volume of one cubic metre to impact on the comet Tempel 1, OSIRIS observed the cloud of dust created by this impact from a distance of around 80 million kilometres. And the instrument succeeded in taking a first picture of the targeted comet as early as summer 2011 - something which required 13 hours exposure time and sophisticated image processing, since the probe and comet were around 163 million kilometres apart at the time.
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Since then, the camera has been taking a rest - as have the other parts of the probe - in energy-saving hibernation. Rosetta’s eyes will first open again in the coming months - and direct their view towards another uncharted world.
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