Well, the European Space Agency has done it! The Philae lander has successfully touched down on Comet 67P.
Itâs pretty incredible. Weâve landed robotic payloads on the Moon, Mars, Venus, and Titan, but we knew about those bodies before attempting those landings. We didnât have that luxury with the Rosetta mission. The spacecraft and lander were built over a decade ago for a landing environment we didnât know all that much about. Rosetta only got the chance to survey Comet 67P and look for a suitable landing site once it was in orbit around it and committed to landing on that cometâs surface.
That was one big part of this mission that could have gone wrong this morning. Comet 67P is an irregularly shaped moving target, and while scientists picked the nominal “landing site J” weeks ago there was no guarantee that the Philae lander would make it to that spot. It could have come down on a really uneven spot or a cliff face, something that would have been unsurvivable for the lander. And of course, the landing was totally autonomous. It takes about a half-hour for a signal to travel between Rosetta and Earth so there was no chance for any real-time course corrections.
Close-up of the region containing Philaeâs primary landing site J.
But Philae went in for a landing this morning and nailed it. About six minutes after 8am PST, ESA started getting telemetry from the spacecraft, confirming that it was on the cometâs surface safe and sound.
But that telemetry isnât telling the whole story just yet. We donât know exactly where the lander has touched or how everything went. Data says the landerâs legs buckled only about an inch and a half, suggesting that the landing was pretty soft. But thereâs one piece of data thatâs missing thatâs a little worrying — the landerâs harpoons have not anchored it to the comet.
Comet 67P isnât big, which means the pull of its gravity isnât very strong. Thatâs why the Philae lander has harpoons. Without those anchors firmly in place, Philae’s landing might be a little on the tenuous side.
But still, the lander is down and we can add comet to the list of celestial objects weâve visited. And as more data comes back from the lander we can get into the really fun stuff: the science! Because thatâs the crux of space exploration. Itâs not about flash, itâs about knowledge. As CEO of UK Space Agency Dr. David Parker said this morning, “Hollywood is good but Rosetta is better!”
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Featured image — the Philae lander after separation with its legs splayed out — via ESA
What the scientists aren’t telling us is this landing knocked the comet slightly off orbit, so the next time it passes earth it’s going to actually enter the atmosphere and crash into New Jersey.
Unless of course we find a brave crew willing to go into space and blow it up…I for one don’t want to miss a thing.