The Rosetta spacecraft's Philae lander successfully touched down on a speeding comet today after a 10-year journey through the solar system.
The European Space Agency's Rosetta already had gone where no other spacecraft has ever attempted to go before, becoming the first to rendezvous with a comet -- in this case one that can move at more than 80,000 miles per hour.
"It's a great day, not only for ESA but for the world. We landed and Philae survived the landing and we have landed at the right place. It's the right comet, don't worry," Jean-Jacques Dordain, the ESA's director general, said to laughs.
While the landing was smooth, it didn't go perfectly according to plan, Stephan Ulamec, the Philae Lander Manager, said at a news briefing.
"The not so good news is that the anchoring harpoons did not file so the lander is not anchored to the surface," Ulamec said.
The ESA said its team is exploring its options for refiring Philae's harpoon rockets, which allow it to remain anchored to the low-gravity comet.
"What we know is that we touched down," Ulamec said. "We had a very clear signal there and we also received data from the lander."
ESA officials speculated that it was possible Philae landed in a soft sandbox-like area. However, the agency said it was not immediately clear what allowed the lander to remain on the comet.
Some of the data also indicates the lander may have lifted off again and bounced, meaning Philae may have landed twice today on the comet.
More analysis of @Philae2014 telemetry indicates harpoons did not fire as 1st thought. Lander in gr8 shape. Team looking at refire options— ESA Operations (@esaoperations) November 12, 2014
The spacecraft's Philae lander began the final leg of its journey this morning when it separated from its mother ship and made a seven-hour journey to land on 67P shortly after 11 a.m. ET. The rubber duck shaped comet is less than three miles wide, making the landing an even more impressive feat.
The Rosetta Lander Imaging System, a camera attached to Philae, took a breathtaking photo of the comet less than two miles away from its surface, providing an incredible close-up look.
Scientists at the ESA will now spend the coming days and months analyzing data they receive from Philae's instruments.
For some perspective on how long communications can take: When Rosetta phoned home today to the ESA's mission control in Darmstadt, Germany, during the final stretch of the journey, it took 28 minutes for the signal to reach Earth, traveling more than 317 million miles.