The European Space Agency’s Philae lander spacecraft landed on the 67P/Churyumov-Gerasimenko comet last year, but had not communicated anything back to earth until now as the solar battery seemed to run out and the lander went to sleep just 60 hours after it reached the surface. But the craft sent signals that were received at the ESA European Space Operations Centre in Darmstadt to say that it was awake and operating.
The lander collected around 8000 data packets which have now been sent to the Rosetta team and are being analysed. The status data received suggested that the lander may have been awake for a while but had not been able to communicate with earth. The data is likely to tell scientists what happened to the lander after it woke up from hibernation. The exact location of the equipment on the comet’s surface may have been discovered using data from the craft and images from the mothership.
When new signals were received from the Philae, the project amanger Dr Stephan Ulamec announced “Philae is doing very well. It has an operating temperature of -35 degrees Celsius and 24 Watts available”. Tweets were sent from both the official Philae Lander and ESA Rosetta Mission Twitter accounts which simulated contact between the two- Philae Lander said “Hello @ESA_Rosetta! I’m awake! How long have I been asleep?” to which a reply came “Hello @Philae2014! You’ve had a long sleep, about 7 months!”.
Before the Philae lander went into hibernation, it discovered organic molecules on the planet and the results of this have been sent back to scientists from one of the ten instruments on the lander called Cosac. Organic molecules can consist of gas, liquid or solid which contains carbon atoms. Data from the Mupus component onboard the lander sent back information which suggested that the comet’s surface was covered with a layer of 10cm to 20cm of dust with ice underneath.
The lander will now work to explore the surface of the planet by analysing the material that it is made from. The Rosetta probe that released Philae onto the comet may have its orbits changed by the scientists in charge of the equipment in an effort to keep communication signals strong.
The Philae lander originally reached the 67P/Churyumov-Gerasimenko comet in November but subsequently bounced and then settled in the shadow of a cliff. Because of this, the lander wasn’t able to absorb as much sunlight as hoped in order to use the solar power as electricity. Therefore, it was only able to communicate with scientists for 60 hours before powering down, during which time it was able to conduct experiments and send the results down to earth. The Rosetta team had managed to lift the Philae up by about 4cm before twisting it by 35 degrees in order to help the solar panels absorb more sunlight, but it was at this point that they discovered the battery was draining rapidly.
It is likely that contact was able to be made as the comet drew closer to the sun because this changed the shape of shadows on the comet’s surface and allowed the equipment’s solar panels to reach sunlight again. The comet will be as close to the sun as it will get on 13th August and will then start to move away. The Philae should be able to hold power until October, by which time it will have run out of power and may never awaken from its next sleep.
The Rosetta orbiter traveled for ten years at a speed of around 41,000mph to reach the 67PChuryumov-Gerasimenko comet, which is 311m miles from Earth. This is the first mission which has orbited a comet and successfully landed a probe on a comet’s surface. While the landing had not been perfect as the Philae’s anchors has failed to fire, the ESA saw the mission as a success are likely to be thrilled that they have made more contact with the craft and received more data. The purpose of the mission is to analyse the surface and try to find out more about space as comets are made from materials older than our solar system.