Some of the initial data sent by Philae has now been analysed. The mass memory constructed by the Finnish Meteorological Institute (FMI) seems to have been storing information about Philae's activities probably since the beginning of this year.
The first sign of life from Philae was received on the evening of 13 June when a weak but clear radio link was formed between the mothership Rosetta and the landing unit Philae. The total duration of the link was 85 seconds. According to a preliminary analysis of the data the situation looks very good as the data received from Philae during the short radio contact reveal that there is as many as 300 data packets i.e. 663 kbits awaiting transmission to Earth.
The gathered data includes the system status data, temperature and electrical system data. "At the moment it looks as if Philae restarted its operations as early as the beginning of this year and has been recording data into the mass memory since then," says Research Manager Walter Schmidt from the Finnish Meteorological Institute. At the moment Philae seems to be active for around 70 minutes during the 12-hour day on the comet.
Philae's CDMS (Command and Data Management System) includes a mass memory developed and built at FMI. The mass memory has now proved invaluable as it has been collecting and storing data from as early as the beginning of the year, even though it has not been possible to establish a radio contact with Earth. "This is really big news, not only regarding the mission, but also for FMI," says Research Professor Minna Palmroth.
"Based on data retrieved from the mass memory, it has already been possible to check that the equipment on the lander seems to be in working order and that the lander's hibernation state does not seem to have caused any major damage." Teams at the European Space Agency (ESA) are now considering how to proceed with the operation as efficiently as possible. Before it is possible to give the first commands to Philae for conducting scientific measurements, a more stable connection between Rosetta and Philae is needed. The first measurements will be made by FMI's PP instrument. The PP instrument will focus on searching water on the surface of the comet.
On Sunday 14th the ESA team was able to establish a link with Philae for a few seconds, and found out that the temperature on Philae had risen to -5 degrees. Most of Philae's solar panels now work to such an extent that the power obtained is 24 W at the best. A radio link requires around 19 W to operate. "From this we can conclude that we are very close to being able to establish more stable radio contact between Rosetta and Philae," estimates Walter Schmidt.
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