Chère Europe et chère Terre, l'atterrissage sur la comète s'est fait en douceur (presque) comme prévu
Voici une vision de ce à quoi devait ressembler mon atterrissage en douceur :
Preparing for #CometLanding
Voici le fil des évènements tel que vu par la caméra Osiris de l'orbiteur Rosetta :
Le paysage local est très sombre et froid, le sol ressemble à de la glace dure couverte de poussière
La preuve par l'image ...
... le thermomètre (qui indique environ - 163 °C) ...
Before going into hibernation in the early hours of 15 November 2014, the Philae lander was able to conduct experiments and return its data to Earth. In this blog post we look at the preliminary analysis conducted by the lander’s Multi-Purpose Sensors for Surface and Subsurface Science instrument package, MUPUS...The first touchdown recorded by Philae occurred at 15:34 GMT (with the signal arriving on Earth at 16:03 GMT), but it later transpired that the harpoons and ice screws did not deploy as planned and the lander subsequently rebounded, experiencing two further touchdowns, at 17:25 and 17:32 GMT (spacecraft time), respectively.Because part of the MUPUS package was contained in the harpoons, some temperature and accelerometer data could not be gathered. However, the MUPUS thermal mapper, located on the body of the lander, worked throughout the descent and during all three touchdowns.At Philae’s final landing spot, the MUPUS probe recorded a temperature of –153°C close to the floor of the lander’s balcony before it was deployed. Then, after deployment, the sensors near the tip cooled by about 10°C over a period of roughly half an hour.
Posted on 18/11/2014 by emily
...et la sonde Mupus (dont la foreuse n'arrive plus à creuser):
The probe then started to hammer itself into the subsurface, but was unable to make more than a few millimetres of progress even at the highest power level of the hammer motor.
“If we compare the data with laboratory measurements, we think that the probe encountered a hard surface with strength comparable to that of solid ice,” says Tilman Spohn, principal investigator for MUPUS.
Looking at the results of the thermal mapper and the probe together, the team have made the preliminary assessment that the upper layers of the comet’s surface consist of dust of 10–20 cm thickness, overlaying mechanically strong ice or ice and dust mixtures.
At greater depths, the ice likely becomes more porous, as the overall low density of the nucleus – determined by instruments on the Rosetta orbiter – suggests.
Posted on 18/11/2014 by emily
Après avoir bien travaillé je vais aller dormir (un peu?)
L'incroyable odyssée de Philae est probablement terminée. Le petit robot, posé sur la comète Tchouri, s'est «éteint», a annoncé vers 2h30 dans la nuit de vendredi à samedi l'Agence spatiale française sur son compte Twitter.
Mais, un peu comme un téléphone portable dont la batterie serait déchargée, il ne fonctionne plus, mais il n'est pas mort, insistent les scientifiques...
Ces derniers espèrent que le robot pourra sortir de son hibernation en août. A ce moment-là, la comète sera «active comme un diable, elle sera très près du soleil», a dit un des scientifiques. Avec un peu de chance, les batteries solaires du robot emmagasineront de la chaleur ce qui lui permettrait de se réveiller et de se remettre au travail.
Tanguy de l'Espinay, Sébastien LernoudPublié le 14.11.2014, 12h37 | Mise à jour : 15.11.2014, 19h07
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