For the period of time before and after the Philae landing, Rosetta was able to orbit the comet close enough that it was in gravitationally bound orbits, circling the comet's center of gravity. As the comet's activity increases, the spacecraft has to spend most of its time farther away, performing occasional close flybys. The first of these is at 6 kilometers, on February 14.
The first results of the Rosetta mission are out in Science magazine. The publication of these papers means that the OSIRIS camera team has finally released a large quantity of closeup images of comet Churyumov-Gerasimenko, taken in August and September of last year. I explain most of them, with help from my notes from December's American Geophysical Union meeting.
This morning ESA released a set of images of the Philae lander taken by the Rosetta orbiter during -- and after -- the lander's first touchdown. The images contain evidence for the spot Philae first touched the comet, and a crucial photo of Philae's position several minutes into its first long bounce.
I'm just getting up to speed on the news from overnight, which is mostly good: Philae remained in contact with the orbiter (which means the CONSERT radar sounding experiment was working), and it's sitting stably on the surface, although it's not anchored in any way. And they released the first ÇIVA image from the ground!
The landing happened on time just after 16:02 UT today! Philae mission manager Stephan Ulamec said: "Philae is talking to us! The first thing he told us was the harpoons have been fired and rewound. We are sitting on the surface." Those words later turned out not to be true; but we do know at least that Philae survived the landing and is returning good data.
Philae is "go" for landing. But there has been drama overnight. One of the steps to prepare for landing did not proceed as planned. UPDATE: At 09:03 UTC, the lander separated from the orbiter, beginning a 7-hour descent to the surface of the comet.
It's been a day of calm before the storm here at the European Space Operations Centre in Darmstadt, as we get ready for the big event tomorrow: Philae's hoped-for landing on a comet. The first of four "go-no-go" decisions has been made, and it's a "go." Mission navigators have gotten data back from Rosetta that indicates that the spacecraft is on the correct trajectory to deliver Philae to the comet.
I'm reporting live from the press room at the European Space Operations Centre in Darmstadt, Germany. There's little news on Philae yet except that its status is good. Meanwhile, Rosetta scientists presented their first early comet results at the Division for Planetary Sciences meeting in Tucson, Arizona, which I watched from afar using Twitter.
Earth's first-ever landing on a comet is a week away. On November 12 at 8:35 UT, Philae will separate from Rosetta. Seven hours later, it will arrive at the surface of the comet. Hopefully, Philae will survive the landing, and begin to return data.
I have been horribly behind in posting images from Rosetta's exploration of comet 67P/Churyumov-Gerasimenko, and that's a shame, because the spacecraft has lately been exploring the comet from a range of only 10 kilometers. From that range, the NavCam gets sub-meter resolution, and we're seeing a menagerie of odd surface features
ESA announced today that Philae will be landing on November 12, 2014. What time the landing occurs depends on which landing site they use. If they go to the prime landing site, "site J," Earth should receive word of the successful landing at 16:00 UTC (08:00 PST). If they go to the backup site, "site C," news will reach Earth at about 17:30 UTC (09:30 PST). Mark your calendars!