Archive for November 6th, 2010

Successful completion of the EPOXI mission

On November 4th exactly at the appointed time, the Deep Impact spacecraft made a close flyby of the nucleus of Comet 103P/Hartley 2. At the moment of closest approach the distance to the comet was all of 700 km, which allowed for the most detailed pictures of a comet’s nucleus in the history of spacecraft studies of such objects. The spacecraft flew by the nucleus at a speed of 12.3 km/sec, having taken five stunning images.

In the pictures, craters covering the surface of the nucleus and powerful jets of material blasting out into space are clearly visible. It is worth noting that before this flight scientists knew the basic shape of the nucleus – an assymetrical dumbbell. These data were obtained from radar observations of the comet’s nucleus made at the end of October with the aid of the gigantic 300 meter Arecibo radio telescope. The results obtained after data processing and analysis, were fully confirmed on November 4!

The size of the nucleus of Comet 103P/Hartley 2 turned out to be rather small, 2.2 x 0.5 km. At the upper left you can see the relative sizes of all the comet nuclei which have been studied during a close flyby of a spacecraft. The first investigation of a comet nucleus by direct flyby was accomplished in 1986. Its target was Halley’s comet. In all, detailed images have been obtained for five comets (1P/Halley, 19P/Borrelly, 81P/Wild 2, 9P/Tempel 1, 103P/Hartley 2). Moreover, three comets were studied by the same spacecraft – Deep Impact.

Now we await what will happen with the mission of this spacecraft in the future; will its existence come to an end or will it be directed to a new target?

November 2010
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