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Philae descends on to the 67P/Churyumov-Gerasimenko comet in November 2014.
Philae descends on to the 67P/Churyumov-Gerasimenko comet in November 2014. Photograph: ESA via Getty Images
Philae descends on to the 67P/Churyumov-Gerasimenko comet in November 2014. Photograph: ESA via Getty Images

Philae is hibernating, says European Space Agency as it calls off searches

This article is more than 9 years old
Probe that touched down on comet in November is expected to ‘wake up’ and signal location when its solar panels re-activate in summer

European Space Agency controllers have called off the dedicated search for Philae, the probe that landed on a comet in November last year.

Instead, they will now rely on “co-riding” opportunities presented by the planned mission programme for Rosetta, the lander’s orbiting mothership.

Scientists still do not know precisely where Philae touched down on 67P/Churyumov-Gerasimenko on 12 November, after bouncing twice on the icy comet when its anchoring system failed.

Studies of images taken by the orbiter have shown Philae crossed a large depression, Hatmehit, before coming to rest at an angle, close to the wall of a crater or cliff.

Data from one of the probe’s instruments suggests it should be somewhere on a “landing strip” on the duck-shaped comet’s smaller lobe measuring 350 metres (1,148ft) by 30 metres (98 feet).

Esa has also released the full image-sequence of the dishwasher-sized craft drifting away from Rosetta at the start of its descent.

Continued close fly-bys to search for Philae will be difficult as the comet gets closer to the sun and becomes more active, spewing out jets of gas and dust.

The orbiter is now circling the comet from a distance of 18.6 miles (30km).

One planned fly-by on 14 February will see Rosetta sweep just 3.7 miles (6km) above 67P, but the quick pass will be far from Philae’s landing spot.

Rosetta’s British project scientist, Dr Matt Taylor, said: “Rosetta’s busy science schedule is planned several months in advance, so a dedicated Philae search campaign was not built into the plan for the close fly-by.

“We’ll be focusing on ’co-riding’ observations from now on; that is, we won’t be changing the trajectory of Rosetta to specifically fly over the predicted landing zone in a dedicated search, but we can modify the spacecraft pointing and/or command images to be taken of the region if we’re flying close to the region and the science operations timeline allows.”

Philae was put in hibernation as its batteries died with its solar panels in shadow.

Scientists hope there will be enough sunlight by May or June to allow the lander to wake up, re-establish a communication link, and send back a “hello” signal.

“We are already discussing and preparing which instruments should be operated for how long,” said lander project manager Dr Stephan Ulamec.

Philae’s landing on a fast-moving comet 300 million miles away has been hailed as one of humankind’s greatest scientific achievements.

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