Precious data sent before Philae's nap

Scientists are hailing Philae's flight and landing as an outstanding success. Photo / AP

After an incredible 10-year journey to become the first spacecraft to land on a comet, the Philae lander gave up the ghost - but not before it managed to transmit a treasure-trove of scientific data to Earth.

Mission controllers put the European Space Agency (ESA) lander to sleep after the charge in its solar-powered batteries fell to dangerously low levels when the craft became lodged in the shadow of a crater wall.

An ESA blog post said: "Philae has fallen into 'idle mode' - a possibly long silence. In this mode, all instruments and most systems on board are shut down."

Scientists are hailing Philae's flight and landing - described as the equivalent of aiming a fly at a speeding bullet - as an outstanding success.

The lander managed to deploy its instruments, including an ice pick drill and hammer, to obtain surface samples for analysis. The information includes results from sophisticated devices designed to analyse the comet's chemical make-up and throw new light on what could have been the building blocks of the universe.

Comets bombarding the early Earth are thought to have brought with them large amounts of water, along with complex organic compounds.

"All of our instruments could be operated and now it's time to see what we got," ESA's blog quoted lander manager Stephan Ulamec as saying.

The lander was lifted on Saturday by about 4cm and rotated about 35 degrees to try to pull it out of a shadow so solar panels could recharge the depleted batteries, ESA spokesman Bernard von Weyhe said.

Even if the lander was rotated successfully and is able to recharge its batteries with sunlight, it may take weeks or months until it can send new signals.

Now ESA scientists will evaluate the data and find out if the experiments were successful - especially a complex operation in which the lander was given commands to drill a 25cm hole into the comet and pull out a sample for analysis.

"We know that all the movements of the operation were performed and all the data was sent down," ESA mission chief Paolo Ferri said yesterday. "However, at this point we do not even know if it really succeeded and if it [the drill] even touched the ground during the drilling operation."

Meanwhile, the search for Philae's final landing site continues, with images from the orbiter being closely scrutinised, according to the blog.

Ulamec said there was still a chance the probe could be reawakened as the comet, 67P/Churyumov-Gerasimenko, flies closer to the Sun, allowing more energy to flow into the solar panels and recharge the batteries.

A tweet from the official Philae lander account before contact was lost said: "I'll tell you more about my new home, comet 67P soon ... zzzzz."

Attention will now turn to the spacecraft Rosetta, which is having to manoeuvre from its post-separation path back into orbit. Next year, Rosetta will fly unbound "orbits", making brief fly-bys to within 8km of its surface.

- Telegraph Group Ltd, AP