Information provided by Europe's Philae spacecraft is reshaping scientists' thoughts about these icy bodies on comet 67P/Churyumov-Gerasimenko.
Europe's Philae spacecraft did not have much time to do its work after surviving a bounce landing on the surface of a comet, but information it collected is reshaping scientists' thinking about these icy bodies, research published on Thursday shows.
Philae piggybacked a 10-year ride with Europe's Rosetta spacecraft to comet 67P/Churyumov-Gerasimenko. With the orbiting Rosetta mothership serving as a communications relay, Philae descended to the comet on November 12, 2014, but the lander's ice harpoons and gas thrusters failed to anchor it into the unexpectedly soft surface.
Philae bounced several times before stopping against a cliff wall, where it ran through a preprogrammed, 57-hour series of experiments. So far, attempts to re-establish good radio contact with Rosetta have failed, Philae manager Stephan Ulamec wrote in an email. "At the moment, Rosetta is investigating the southern hemisphere of (the comet), which leads to low chances to contact the lander. After August 8, chances to get Philae signals are better again," he said.
Image shoes the comet from an altitude of 67.4 metres on Novermber 12, 2014. Image Credit: ESA/Rosetta/Philae/ROLIS/DLR
Comets are believed to be remnants from the formation of the solar system 4.6 billion years ago. They contain rock and ice that have preserved ancient organic molecules like time capsules and may provide insight into how the planets and life evolved.
Seven papers published in this week's issue of the journal Science show how productive Philae's time on the comet was. Philae blasted radio waves through the head of the duck-shaped comet that were picked up by Rosetta on the other side, revealing the comet's surprisingly uniform interior, one study shows.
Images taken during Philae's descent found the comet has a fractured and highly reflective rock surface, with erosion playing a major role in shaping its features, concludes another.
While Philae was not able to drill out samples from the subsurface for analysis, the lander's initial bounce kicked up dust that ended up in instruments designed to detect organic compounds. Scientists report they found 16 types of organics, including four previously unknown to exist on comets.
Watch: Rosetta lander science
Philae's landing also provided an unexpected discovery about variations in the comet's surface. Philae's intended landing site appears to be covered with about 10 inches (25 cm) of soft, granular material, with a hard layer beneath. "Before the landing of Philae, we believed, cometary surfaces might be very soft … Some colleagues even feared the lander may sink deeply into the surface at touchdown," Ulamec said.
Sequence of Rosetta navigation camera images taken between 1 and 6 August 2014, during the approach to comet 67P. Image Credit: ESA/Rosetta/NAVCAM
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