Philae’s first comet photos include ominous signs of probe’s fate

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Scientists involved with the Philae comet lander are working with the first surface images returned from the robot probe and the results are both spectacular and ominous.

Spectacular because the photos confirm the lander is at rest on the surface of the comet and able to transmit data back to Earth.

Ominous because they show Philae has settled in a tipped orientation, which could severely affect the lander's science capabilities and leave it unable to recharge fully to survive more than a few days.

Images returned by the lander overnight show that one of its feet is pointed skyward with a dramatic cliff looming behind it.

"We are almost vertical," said Jean Pierre Bibring, lead scientist for the lander, during a press briefing at the European Space Operations Centre.

Philae separated from the Rosetta spacecraft Wednesday and made its first contact with Comet 67P/Churyumov-Gerasimenko at 11:03 a.m. (ET) after a seven-hour descent. Both spacecraft are operated by the European Space Agency.

The comet is currently moving at 18 kilometres per second as it orbits the sun with Rosetta in tow.

After the probe's touchdown, Stephan Ulamec, the lander's project manager, confirmed that Philae did not fire two harpoons that were meant to anchor it to the comet's surface. It's still not clear why they didn't fire, he said, but the failure apparently set the lander up for a wild ride.

Data from a magnetometer on board Philae suggest the lander bounced off the low-gravity comet and then rose up about one kilometre above the surface. The lander was then free floating for approximately two hours before it touched down again in a very different location.

Another bounce followed, this time for just seven minutes or so, which brought the Philae to its current location, possibly up against a steep escarpment or crater rim.

The question is, where is that exactly?

Seven images have now arrived from CIVA, the lander's panoramic camera system, said Mark McCaughrean, senior science adviser at the European Space Agency.

One of shows a rough, rock-like surface with dark shadows and one of the lander's three metal legs in the foreground.

The trouble is, it doesn't show a horizon – or perhaps it does. Scientists are still trying to work out if the dark patch on the left hand side of the photo is a shadow or the sky.

The good news: "We're not upside down, like a beached crab. That's for sure," Dr. McCaughrean said.

One of the other photos contains stars and not much else, so it's clear the lander is not sitting horizontally with respect to the surface.

Dr. Ulamec said that the location had been narrowed to a zone that includes a feature that looks like a fairly steep escarpment or crater rim, which could be what the lander is seeing.

Fresh images from Rosetta are now being scrutinized for signs of the lander on the surface.

"We're working our eyes off," said Holger Sierks, principal investigator for Rosetta's high resolution camera, called OSIRIS.

Wherever Philae is, scientists know it's rather dark. Rather than six to seven hours of sunlight each comet rotation period, as planned, the lander's solar panels are getting sunlight for only 1.5 hours.

That may not be enough to allow batteries to recharge. The batteries are needed not only to power the science instruments but to keep the lander warm enough to survive through interval without sunlight.

By next summer the comet will be at its nearest point to the sun and scientists hope to use Rosetta to document the expected increase in surface activity as the comet's icy constituents begin vapourizing under the sun's warming glow. Philae will not last nearly that long on the comet's surface, but if the lander can get through the next few days and recharge itself repeatedly, it could survive as long a few months.