After seven months of torpor to “tchouri”, the robot wakes … Philae – The World

Le Monde | 06/14/2015 at 13h35 • Updated 06/14/2015 at 19:19 | By David Larousserie

“Philae is operational” , said on Sunday June 14 Stephan Ulamec responsible for this thing to European Space Agency (ESA). This mini-laboratory, which is placed on comet 67P Churyumov-Gerasimenko since November 12, so finally gave his news. Shortly before midnight Saturday, the teams received a brief signal during forty seconds from Rosetta orbiter that scrutinizes the evolution of the comet since August 2014 and had dropped Philae on its frozen and dusty ground, some 500 million kilometers from Earth. A first.

Sixty hours after landing and after early experiments in situ, Philae had stopped for lack of battery and entered into hibernation. Since March 12, ESA’s teams were monitoring every month for about a week, a possible signal that would have informed the robot health.

Read also: Astronomy: attempts to reconnect with the robot Philae began

The fourth attempt was good. The signal finally arrived with good news. Solar panels work because they were able to bring the 19 watts needed to transmit the signal. The first data received indicate that even 24 watts are available. The internal temperature has risen above – 45 ° C, from which the onboard computer can work. “We are happy. We’re going to work on these data and those that follow “ enthuses Jean-Pierre Bibring, chief scientist of Philae and astrophysicist from the University Paris Sud (Orsay).

Only flat, communication between Rosetta and Philae is very short, a few minutes instead of the expected contact hour. The information therefore arrive intermittently. ESA states have received 300 packages on 8000 in memory.

“This is a first important step to know that Philae is not broken or covered with dust. We find confidence “, says Philippe Gaudon, head of mission operations at the National Centre for Space Studies (CNES).

” We are trying to improve conditions communication between Rosetta and Philae “ says Jean-Pierre Bibring. Rosetta is in orbit about two hundred kilometers from the surface to protect against dust emissions, which increase as the comet approaches the sun.

On February 14, a low-flying just six kilometers from the surface was a record. But a month later, a new fly, above, was a time lose control of the orbiter because of the many dust emitted by the kernel.

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By being so well away, teams must analyze when the orientation and position are most favorable for improve this communication. “At this distance, we do not really talk of orbit, they are rather round trips of estates and straight lines says Philippe Gaudon. So we have to drive differently Rosetta to improve communication. “ sign of these difficulties, two hours after the first signal, a second should have arrived but has not been received.

The task is complicated by the fact that the exact position of Philae is unclear. On June 12, CNES announced yet spotting the small craft on the “head” of the comet, Rosetta with a snapshot. Philae is stuck at the foot of a cliff and not exactly horizontal, which had complicated the realization of the crust of the comet drilling experiments in November

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This position, in the shade, however, has the advantage of having protected the electronics too high temperatures. Thus the new experiences will provide information on a more active core, that is to say, ejecting more gas and dust than originally planned. Computer sequences to download on Philae is ready but can not begin until the “visibility” Rosetta will be better and that communications will last more than thirty minutes. Probably not for another week or two.

Meanwhile, the first scientific results from the experiences of November are ongoing examinations by specialists, for publication this summer.

Rosetta has also brought many results and many questions about the nature of the comet. The nucleus appears to be very porous, with a lower density than liquid water. Ice water in it does not have the same composition as that of terrestrial oceans, spreading the idea that our water would have been made only by collisions with comets. The geological landscapes are much more complex than expected, alternating sandy plains, cliffs and chasms unfathomable

Read also:. Rosetta and surprises of comet “tchouri”

It is unclear what the exact composition of the organic matter present on Churyumov-Gerasimenko, whether terrestrial life would have been favored by the contribution of these biochemical building blocks in a rain of comets similar.