It was the first ever landing on a comet, and it was perfect.
Unfortunately, that wasn't the end of the journey for the European Space Agency's unmanned Philae lander. After touching down on Comet 67P/Churyumov–Gerasimenko, the lander bounced off the surface and flew a kilometer back up into space.
Newly released photos taken by the Rosetta spacecraft orbiting the comet clearly show the lander on the rebound. Scientists know that first bounce took nearly two hours, and that the probe eventually bounded into a cliff. The enormous bounce was the result of the comet's tiny gravitational pull: Philae weighs more than 200 pounds on Earth, but on the comet, it weighs as much as a sheet of paper.
The German Space Agency, a partner of the European agency, has released the early findings from the lander. They indicate Comet 67P's surface is far harder than previously thought — and that organic compounds are present. Some researchers believe that comets brought water and the building blocks of life to earth billions of years ago.
The lander's final resting spot on the comet remains a mystery, but scientists were able to get in touch and transmit data back from Philae. It had enough battery power to run its scientific instruments for approximately 60 hours after touchdown. The results were received here on Earth late on Friday night East Coast time.
MUPUS is a multipurpose sensor designed to understand the the physical properties of the comet's surface. It was equipped with a hammer designed to try and crack through the comet's crust, a battle the tool lost. The hammer was unable to break the solid surface of the comet, even when the team increased its power to "desperate mode." Instead, the tool broke.
But even this taught them something about the comet's bizarre surface. Although the ground looks fluffy, like cigar ash, it appears to be quite hard.
In a perfect world, the lander would have fired harpoons at touchdown, securing it to the right landing site. Solar power would have allowed the lander's tools to operate for months as the comet approached the sun. MUPUS would have cracked the surface, and scientists would have learned loads more.
That didn't happen, but researchers still see the landing mission as a spectacular success.
"This was such a risky thing and a brave thing to do," says Jessica Sunshine, a researcher at the University of Maryland who has worked on several NASA comet missions. "The fact that they've gotten as much data that they have, you know, it really is amazing."