The comet lander Philae has finally phoned home

ROSETTA’S PHILAE LANDER has awoken on the surface of Comet 67P/ChuryumovGerasimenko after a long hibernation. ESA mission controllers were thrilled to receive signals from the lander in mid-June, when the comet moved close enough to the Sun to charge up the lander’s solar-powered batteries.

The Rosetta spacecraft, which is currently orbiting the 4km-wide comet, dropped Philae onto the dusty snowball’s surface in November last year. But the lander communicated for only 60 hours because it fell into a shadowy ditch, where its solar panels received very little sunlight.

Scientists hoped the lander would ‘reawaken’ as the comet moved closer to the Sun. And sure enough, after seven months of silence, it made contact again on 13 June.

“Philae is doing very well – the lander is ready for operations,” said Stephan Ulamec, ESA project manager for Philae. “All lander subsystems are working nominally, with no apparent degradation after more than half a year hiding out on the comet’s frozen surface.”

Since then, the first priority has been to assess the lander’s position and orientation, then measure environmental features such as temperatures and magnetic fields. If Philae’s batteries continue to power up, it will hopefully beam back sharp images of the weird cometary landscape and eventually drill into the surface to analyse its chemical composition.

The mission remains precarious for both Rosetta and Philae, however, because the comet will continue to heat and activate, fizzing out gas and dust unpredictably. It will make its closest approach to the Sun on 13 August.

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