21st July 2014

New images of comet as Rosetta probe nears target

The European Space Agency has released striking new images of comet 67P/Churyumov-Gerasimenko. As part of the Rosetta mission, a robotic lander will be deployed on the surface.

As the Rosetta spacecraft nears its destination – comet 67P/Churyumov-Gerasimenko – the object is proving to be full of surprises. New images obtained by OSIRIS, the onboard scientific imaging system, confirm the body's peculiar shape hinted at in earlier pictures. Comet 67P is obviously different from other comets visited so far.

"The distance still separating Rosetta from 67P is now far from astronomical," said Holger Sierks, OSIRIS Principal Investigator from the Max Planck Institute for Solar System Research (MPS) in Germany. "It's a trip of less than 14,000 kilometres [about 8,700 miles]. That's comparable to travelling from Germany to Hawaii on a summer holiday."

However, while taking a snapshot of Mauna Kea, Hawaii's highest mountain, from Germany is an impossible feat, Rosetta's camera OSIRIS is doing a great job at catching ever clearer glimpses of its similarly sized destination. Images obtained on 14th July show a tantalizing shape. The comet's nucleus consists of two distinctly separated parts.

"This is unlike any other comet we have ever seen before," said OSIRIS project manager Carsten Güttler from the MPS. "The images faintly remind me of a rubber ducky with a body and a head." How 67P developed this intriguing shape is still unclear. "At this point we know too little about 67P to allow for more than an educated guess," said Sierks.

Later this year, the scientists hope to determine more of the comet's physical and mineralogical properties, which may help to confirm whether its body and head were formerly two individual bodies. In November, the probe will come within 2.5 km (1.5 miles) of the comet and deploy a small robotic lander called Philae. This will take around two hours to reach the surface, using a harpoon system to counter the extremely low gravity. Screws will be drilled to anchor its feet in place, as shown in the video below.

Once attached to the comet, the lander will begin its science mission – using ten instruments to characterise the surface, sub-surface and nucleus, determine the chemical compounds present and study the comet's activities over time. Six cameras mounted on the sides at 60° intervals will provide a 360° panorama around the lander.

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