Rosetta Spacecraft To Start Listening For Signs That Philae Is 'Alive'

Scientists are about to turn on Rosetta's communication system in the hopes of getting a signal from the crash-landed Philae probe that landed on Comet 67P/Churyumov-Gerasimenko back in November 2014.

After the probe's safe-landing systems failed, it reportedly bounced off the comet's surface before finally coming down to rest. Unfortunately the landing site was completely in the shade, preventing Philae from getting the energy it needs to operate.

To try and preserve the mission, ESA scientists put Philae into a deep sleep state waiting for the moment when the comet's trajectory would place Philae back in the sunlight.

Well that point has arrived according to Lander Project Manager Stephan Ulamec, "Philae currently receives about twice as much solar energy as it did in November last year,”

Ulamec doesn't want us to start jumping up and down just yet though: “It will probably still be too cold for the lander to wake up, but it is worth trying. The prospects will improve with each passing day,”

Before Philae can even begin transmitting a signal, there are a number of conditions that have to be met:

  • First, the interior of the lander must be at least at –45ºC before Philae can wake up from its winter sleep. At its new landing site – Abydos – only a little sunlight reaches Philae, and the temperatures are significantly lower than at the originally planned landing location.
  • In addition, the lander must be able to generate at least 5.5 watts using its solar panels to wake up.

Once both those conditions have been achieved, Philae will start sending out a signal every 30 minutes which can then be picked up by Rosetta, which has been tailing the comet since it arrived.

There's a lot still to be discovered so the ESA is stressing that any outcome is possible. Until they receive the signal from Rosetta, they won't even know if Philae has survived its sleep.