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Physical Chemistry

Rosetta’s Probe Touches Down On Comet

Space: Historic landing marred by failure of anchors, but science data are streaming in

by Elizabeth K. Wilson
November 12, 2014

The frequency of oscillations of comet 67P/Churyumov-Gerasimenko’s magnetic field are increased by 10,000, to make an audible “song.”
Credit: ESA

In a first for human space exploration, a spacecraft has landed on a comet. But although the lander’s instruments appear to be working, harpoons that would anchor the probe to the comet have so far failed to deploy.

The European Space Agency’s Rosetta spacecraft spent 10 years en route to the comet 67P/Churyumov-Gerasimenko, 300 million miles from Earth. It deployed its lander Philae to the comet’s surface on Nov. 12. If all goes as planned, Philae will spend two-and-a-half days drilling into the 2.5-mile-diameter comet and analyzing its chemical makeup.

Team scientists at the Philae Science, Operations & Navigation Centre at France’s National Center for Space Studies (CNES) in Toulouse cheered and hugged as they received the landing confirmation signal from Rosetta at 11:05 eastern time.

It’s not yet clear whether Philae’s stability will pose a problem. Scientists are debating attempting to redeploy the harpoons, knowing that they risk upsetting the lander.

Stephan Ulamec, Philae lander manager, says the team doesn’t yet understand what happened, but it’s possible Philae may have bounced after landing.

But in the meantime, ESA is celebrating.

“This is a big step for human civilization,” says Jean-Jacques Dordain, director general of ESA. He underscored the enormous effort and anticipation of the Rosetta team, noting that “the biggest problem of success is that it looks easy.”

Credit: ESA/Rosetta/Philae/ROLIS/DLR
The lander craft Philae snapped an image 3 km from the surface of comet 67P/Churyumov-Gerasimenko.
Credit: ESA/Rosetta/Philae/ROLIS/DLR
The lander craft Philae snapped an image 3 km from the surface of comet 67P/Churyumov-Gerasimenko.

Comets are composed of chunks of dust and ice from the solar system’s genesis and loop around in elliptical orbits. Because comets represent time capsules of the early solar system, scientists have keen interest in understanding comets’ chemical makeup.

In 2005, the National Aeronautics & Space Administration’s Deep Impact orbiter smashed a 300-lb chunk of copper onto the surface of the comet Tempel 1. The craft found organics in the dust and ice that was kicked up.

Philae’s 10 instruments, which include an α-proton X-ray spectrometer and gas analyzer, could make even more sophisticated detections.

“We know that comets produce organic molecules, such as amino acids and peptides,” says John Plane, professor in the atmospheric and planetary chemistry group at the University of Leeds, in England. “The really big result will be if Philae detects chiral amino acids,” he adds.

Rosetta, which was launched in March 2004, contains a payload of 16 observing instruments and will continue orbiting the comet throughout 2015.



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