Philae's battery is running down fast


After being cited by solar enthusiasts the world over – including pv magazine – as an example of the power of solar on Wednesday, the Philae comet landing craft could yet come to embody the pitfalls of the renewable energy.

The initial euphoria surrounding the feat of a first-ever landing on the surface of a comet this week was swiftly tempered by the news failures in the thrust system and grappling harpoons on the lander left it upended in shadow and swiftly running down its batteries.

The world watched as the Philae lender sent back its first images of the surface of comet 67P/Churuyumov-Gerasimenko on Wednesday but European Space Agency (ESA) scientists fear its primary batteries could have run out by Friday night.

The failures in the thrust system and harpoons during landing saw Philae bounce twice before settling on the comet's surface 1 km away from its intended landing point and on its side in shadow.

In fact, according to reports in the Guardian newspaper and on the Extreme Tech website, the agency does not know exactly where Philae landed and has been using cameras on its Rosetta mothership to try and find it.

Philae was supposed to be receiving between six and seven hours of sunlight in every 24-hour cycle but is only getting 1.5 hours and as a result, its primary battery is running down without sufficient sunlight to charge its secondary batteries.

The ESA has been trying to instruct the lander to turn towards the sun – a difficult operation without knowing where it is and with the device upended – and otherwise face the choice of putting the lander into hibernation mode in the hope of more favorable sunlight conditions in future or of trying to use Philae's movable legs to ‘hop' it into sunlight.

The lander has already supplied vital information about the comet and if it appears likely its useful life may be short, the ESA may opt to try and drill into the comet – something scientists have held off from doing given the absence of the grappling harpoons which were meant to steady Philae while such an operation is performed.

What this – or that – space.

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