14 Jun 2015

Why Philae’s long sleep could be even better than planned

For the scientists who worked for decades to land a robot on a speeding comet, getting there was exciting enough. But now they’ve re-established contact with their probe – missing, believed dead for seven months – they now find themselves at the centre of the greatest comeback story in the history of robots in space.

There was jubilation when Philae touched down on the surface of comet 67-P on November 12th last year. This was by far the riskiest space landing in the history of solar system exploration.

ESA Attempts To Land Probe On Comet

But it was short-lived. When the data started to come back they realised their lander hadn’t initially landed. In the comet’s microgravity it had bounced several times before landing the right way up – but a long way from its planned landing site in the shadow of a cliff. With no sunlight falling on its solar panels, Philae carried out 60 hours-worth of experiments on battery power, before shutting itself down.

Mission managers hoped that as the comet approached the Sun, the amount of light reaching the probe might allow it to re-boot. But many were pessimistic, especially as it had spent months freezing in the dark.

But at 10.30 last night Philae phoned home. It began sending back thousands of packets of data it acquired before it shut down which will give scientists much to work on. If the conditions on the comet stay the same, they hope to carry out many of the experiments they had to abandon when they lost the lander.

They want to use Philae’s drill to dig into the comet’s surface and analyse it for the types of molecules that may have kick-started life on our own planet. They also want to use the probe to receive radio pulses fired through the comet from its mother-ship the Rosetta orbiter.

ESA Attempts To Land Probe On Comet

This will give them the first interior view of a comet — some of the most mysterious objects in the solar system.

And Philae’s enforced hibernation might even be to their advantage, say mission scientists.

If the probe had worked as planned, it probably would have overheated and died by now.

By waking up after seven months it will hopefully be doing experiments as Comet 67-p is closest to the Sun – the most interesting time in a comet’s life.

They now have to opportunity to learn even more than they hoped.

Follow Tom Clarke on Twitter: @tomclarkeC4