The European Space Agency’s Rosetta mission successfully placed a small spacecraft on the surface of a speeding comet on Wednesday. Rosetta took off from Earth 10 years ago carrying Philae and traveled 6.4 billion miles before arriving in early August at the comet.
The agency’s director general, Jean-Jacques Dordain, described the touchdown on Comet 67P/Churyumov-Gerasimenko, a 2.5-mile-wide ball of rock, ice and dust moving faster than 40,000 miles an hour, as “a big step for human civilisation.” Mr. Dordain said at a news conference: “Our ambitious Rosetta mission has secured another place in the history books. (…) “Not only is it the first to rendezvous with and orbit a comet, but it is now also the first to deliver a probe to a comet’s surface.”
Scientists are facing a tense wait to learn the fate of a robot probe that made a historic landing on the comet as Philae did not stay in place as planned. Data from the Philae craft indicates it landed at least three times on the comet, after harpoons failed to attach it to the surface on the first attempt. However Philae sent images of the icy grey comet during its approach.
“The not so good news is that the anchoring harpoons did not fire,” Philae’s landing manager, Stephan Ulamec, said. “So the lander is not anchored to the surface. Did we just land in a soft-sand box and everything is fine? Or is there something else happening? We still do not fully understand what has happened.” He then illustrated the full extent of the landing’s opacity: “Some of the data indicated that the lander may have lifted off again. It touched down and was rebounding. So maybe today, we didn’t just land once, we landed twice.”
Without the harpoons, the washing-machine-size craft will have to rely nearly exclusively on the ice screws at the bottom of its landing legs to grip the comet. It’s unclear whether those are strong enough to hold indefinitely. It “could mean that we are sitting in soft material and we are not anchored,” Ulamec explained.
Furthermore, the whole world is to benefit from the Rosetta findings and what Philae will deliver. “Rosetta is trying to answer the very big questions about the history of our solar system,” Matt Taylor, ESA Rosetta project scientist, said in the article on the ESA website. “What were the conditions like at its infancy and how did it evolve? What role did comets play in this evolution? How do comets work?”