211 days after scientists last heard from the Philae lander from the Rosetta spacecraft, a distant ‘voice’ has been heard! After a particularly bumpy landing, Philae came to rest in an area on comet 67P that didn’t receive much sunlight causing the European Space Agency to wonder whether it would ever have enough energy for it’s solar powered batteries to come back to life.
Imagine their surprise when signals were received at ESA’s European Space Operations Centre in Darmstadt at 22:28 CEST on 13th June. Philae ‘spoke’, via Rosetta, to the ESA team for 85 seconds. “Philae is doing very well: It has an operating temperature of -35 degrees C and has 24 Watts available,” explains DLR Philae Project Manager Dr. Stephan Ulamec. “The lander is ready for operations.”
How big do you think the Philae lander is?
Philae is smaller than the world’s smallest car, or roughly about the size of a regular family dishwasher. It’s job is to provide information and increase our understanding about the composition of a comet. It’s name originates from the obelisk found on the island of Philae, in Egypt, that helped to decipher the hieroglyphs on the Rosetta stone. These insights helped us understand ancient texts and symbols. Philae’s initial tasks are simple ones and include taking the outside temperature and magnetic measurements. When it has more power, it will take photos and examine the comet terrain in more detail. It can ‘sniff’ it’s environment for volatile chemicals but will it ever have enough power to be able to use the Ptolemy instrument to drill and investigate the dust-like surface?
Professor of Planetary Sciences at the Open University who works on Philae’s Ptolemy instrument, said “We are so happy Philae has woken up. We were hoping that this was going to happen. It’s a really exciting time.” Philae’s Ptolemy instrument will be able to analyse samples that have been drilled from the comet’s surface. The samples will be baked in ovens and the gases that are given off can tell scientists more about the composition. However, no one is sure whether Philae’s drill is still able to reach the surface in order to recover dust samples.
Whilst Philae has been asleep, Rosetta has continued to closely study the comet. With 11 science instruments on board, Rosetta has been collecting data from the comet as it flies past at varying heights from several hundred kilometres down to skimming past at only 8km! The Alice spectograph, provided by NASA, is able to examine the chemicals in the comet’s atmosphere at far-ultraviolet wavelengths. By splitting the comet’s light into its various colors, Alice can measure the gases that 67P emits and whether they contain hydrogen, oxygen, carbon or nitrogen.
So far, scientists have been examining the jets of gases coming from the comet and wondering whether they could harbor the necessary chemical components to develop signs of life.
Philae seems to have survived it’s long sleep remarkably well. On Sunday, 14th June, enough data was received to establish that all of the landers systems were functioning normally and that it’s internal temperature had risen to -5 degrees C. Philae has stored over 8000 packets of additional status date in its memory since it woke up. As it continues to restore power by sufficient sunlight sources it is now able to generate it’s own electricity.
Rosetta Mission Manager, Patrick Martin said “Power levels increase during the local ‘comet’ day’ – the part of the about-12 hour comet rotation when Philae is in sunlight – from 13W at comet sunrise to above 24W,” “It needs at least 19W to switch on the transmitter.” He continued.
“While the information we have is very preliminary, it appears that the lander is in as good a condition as we could have hoped,” said Dr Ulamec. With a view to improving communications between Rosetta and the robot, scientisits will attempt to change the level of orbit of the European spacecraft to within 180 kilometres of the comet’s surface. This will enable both stronger and longer levels of communication between Rosetta and Philae. This could be a tricky procedure. If Rosetta is too close to the comet, it’s instruments that tracks the stars for location guidance could malfunction due to comet dust.
Facts about the Rosetta mission:
- Rosetta spacecraft flew six billion kilometres to get to the comet
- The comet orbits the sun at 135,000 kilometres per hour
- The Philae lander touched down on the comet 7 months ago
- Comet is now 215 million kilometres from the sun and 305 million km from Earth
- The comet’s full name is 67P/Churyumov-Gerasimenko or 67P for short.
- You can follow the mission's progress on Twitter: @ESA_Rosetta @philae2014 @Philae_Ptolemy