Philae comet probe got down without harpoons

ESA head of mission operations Paolo Ferri has said that the harpoons meant to anchor the Philae lander to the surface of Comet 67P/Churyumov-Gerasimenko did not actually fire as they'd thought earlier.

But regardless, the craft is reporting that it’s stable on the space-rock, so the team aren’t too concerned yet about how it got there, he said, adding that they were investigating.

Since the harpoons failed to fire, the lander is likely anchored by its three ice-screw legs. These were programmed to drill into the surface on impact to hold Philae in place, since it weighs less than a feather in Comet 67P’s gravity. But ESA is waiting on further information to find out.

Ferri also said that the data from the comet-catching craft, which successfully touched down on the surface of 67P/Churyumov-Gerasimenko earlier this evening, was suffering from brief gaps in communications, though the team isn’t too worried at present.

Data is gathered and saved by the lander and then transmitted in packages to Rosetta before making its way to Earth, so most information can still be downloaded again.

“It’s a vital link, but the fact that it’s being interrupted is a secondary concern. What’s important is that the link is there,” Ferri told the press at European Space Operations Control.

The operations director reckons that Philae managed to get within a hundred metres of the centre of landing site Agilkia, based on the fact that the lander touched down so close to the middle of its landing window.

Ferri said that data last night showed Rosetta was in an “almost perfect” position and the picture from the OSIRIS camera instrument on the space satellite after Philae detached for its landing attempt also showed the probot in the right place.

Along with the lander hitting its timing so well today, the three facts add up to the likelihood that it managed a very good landing indeed, but the space agency won’t be able to confirm that until it gets further information from the lander.

Before the communications window with Philae temporarily closes at 6pm GMT, ESA hopes to get a panoramic picture of the comet surface from the lander, which should help the team to map the probe’s position on Agilkia. ®