Rosetta satellite beams back comet images

24 Jul 2014

The images of Comet 67P/Churyumov-Gerasimenko captured on 20 July by Rosetta's OSIRIS narrow angle camera from a distance of about 5,500 km. Images via ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

The European Space Agency (ESA)’s Rosetta satellite is homing in on Comet 67P/Churyumov-Gerasimenko, as images by the spacecraft’s OSIRIS narrow angle camera from a distance of about 5,500 km reveal.

Scientists ‘awoke’ Rosetta in January from a 31-month hibernation to conserve energy. The satellite’s ultimate goal is to land a probe on the 4.5km-wide comet and gather data.

If the mission is successful, it would make Rosetta the first space mission to rendez-vous with a comet, the first to attempt landing a probe on a comet’s surface, and the first to follow a comet as it swings around the sun.  

The trio of new images, acquired on 20 July and taken two hours apart, reveal surface details of the comet and that it features a smaller ‘head’ connected to a larger ‘body’.

The ‘neck’ of the comet will be of particular interest to scientists, as it will hold clues to the comet’s evolutionary history, a post on the Rosetta Blog states.

“One area of the neck seems significantly brighter than surrounding regions,” the post reads. “This bright region, seen most clearly in the first image, may result from differences in surface composition or grain size. For example, could it be a region of freshly exposed ice or the product of resurfacing. Alternatively, it could be a topographical effect. The cause of this bright region will become clearer once higher-resolution images and spectral data are available.”

Shape model of Comet 67P/Churyumov–Gerasimenko, based on 14 July images. Image via ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Rosetta’s job

Rosetta is expected to reach the comet in August, when it should be at a distance of 70km, at the most, from the comet.

The satellite will then begin extensive mapping of the comet’s surface for two months, and will also take measurements regarding the comet’s gravity, mass and shape, and assess its gaseous, dust-laden atmosphere, or coma.

The orbiter will also probe the plasma environment and analyse how it interacts with the sun’s outer atmosphere, the solar wind.

Using this data, scientists will choose a landing site for the mission’s 100kg Philae probe. The landing has been scheduled for 11 November.

Tina Costanza was a journalist and sub-editor at Silicon Republic