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The Comet Lander Philae - and Rosetta Orbiter latest updates

Philae is Sleeping - Lost Communications


Philae is sleeping. 15 November update. 


With batteries depleted and not enough sunlight available to recharge its batteries, Philae has gone into idle-mode and all instruments and most systems on board have shut down.


However, the lander ‘Philae’ completed its primary science mission after nearly 57 hours on Comet 67P/C-G, and has sent back all of its housekeeping data, including science data from the targeted instruments of; CONSERT, COSAC, Ptolemy, ROLIS, and SD2, which has completed the measurements planned for the final group of experiments on the surface.  


Lost Communication


Due to its orbit Rosetta lost communication with lander Philae on Friday 14 November 2014 at  09:58 GMT / 10:58 CET, and regained contact with the lander on Friday evening at 22:19 GMT /23:19 CET.  At first the signal was intermittent, but quickly stabilised and remained excellent until communications were lost early Saturday morning 15 November at 00:36 GMT / 01:36 CET.


In an attempt to receive more solar energy, Philae was lifted by approximately 4 cm and rotated by about 35°, but as the last of the science data was fed back to Earth, Philae’s power rapidly depleted and went into hibernation.


image credit; ESA

Philae is sleeping. 15 November update.


No further contact will be possible unless sufficient sunlight falls on the solar panels to generate enough power to wake it up. There is the possibility that this may happen later in the mission due to commands sent to Philae that lifted the lander and rotated its main body with its fixed solar panels, which should have exposed more panel area to sunlight. However given the low recharge current available from the solar cells, it is considered unlikely that contact with Philae will be established in the coming days.


Stephan Ulamec, manager of lander Philae, from DLR German Aerospace Agency, who monitored the landers progress from ESA’s Space Operations Centre in Darmstadt, Germany said,  “We still hope that at a later stage of the mission, perhaps when we are nearer to the Sun, that we might have enough solar illumination to wake up the lander and re-establish communication.”

Stephan said, “It has been a huge success, the whole team is delighted. Despite the unplanned series of three touchdowns, all of our instruments could be operated and now it’s time to see what we’ve got.”


Perhaps with a bit of luck, later during the mission, Philae receives enough solar energy to replenish its batteries and wake up. In the meantime Rosetta will continue to orbit comet 67P/C-G for about two more years gathering vital and important information about the comet, and the changes it undergoes as it approaches perihelion (closest point) with the Sun on 13 August 2015. Rosetta orbiter has been moving back into a 30 km orbit around the comet, and will return to a 20 km orbit on 06 December 2014. During the next few months, Rosetta will start to fly in more distant ‘unbound’ orbits and perform a series of fearless flybys past the comet, some within just 8 km of its centre.


Rosetta will continue orbit comet 67P/C-G collecting data and will allow scientists to monitor both short and long-term changes that take place on the comet, which will help in answering some of the most important questions regarding the history of our Solar System. The (ESA) European Space Agency’s, Rosetta project scientist said, “The data collected by Philae and Rosetta is set to make this mission a game-changer in cometary science,”

While ESA’s  mission manager, Fred Jansen, said, “At the end of this amazing rollercoaster week, we look back on a successful first-ever soft-landing on a comet. This was a truly historic moment for ESA and its partners. We now look forward to many more months of exciting Rosetta science and possibly a return of Philae from hibernation at some point in time.”


Rosetta / Philae Mission details

click image to enlarge

European Space Agency (ESA) -  Rosetta Spacecraft - Deep Space Mission

to Comet Churyumov-Gerasimenko (comet 67P/C-G) - latest news and updates


Rosetta Orbiter and lander Philea latest news and updates



a Marvellous photo;


This photograph by Rosetta’s OSIRIS narrow-angle camera, shows the decent and drift of Lander Philae over comet 67P/C-G (67P/Churyumov-Gerasimenko) on 12 November 2014.



When taking these photographs Spacecraft Rosetta was approximately 15.5 / 9.6 miles from the surface of the comet and about 17.5 km / 10.8 miles from the comet’s centre.


The image taken after touchdown, at 15:43 GMT/UT confirms that Philae was moving east, and at a speed of approximately 0.5m/s, which was first indicated by data returned by the CONSERT experiment.


The final location of lander Philae is still unknown but the imaging team is confident that by combining the CONSERT ranging data with OSIRIS, and other navcam images from orbiter Rosetta, plus other images taken by lander Philae’s ROLIS and CIVA cameras, will soon reveal the location of Philae.


Photo image resolution is; 28 cm per pixel, and the enlarged insets are 17 x 17 m.


click image to enlarge.

Rosetta’s OSIRIS narrow-angle camera, shows the decent and drift of Lander Philae over comet 67P/C-G

Update 18 November 2014 - from Philae's MUPUS instrument


MUPUS marked in green on diagram (click diagram to enlarge)


First indications from Philae's MUPUS instrument suggest that the lander touched down in a 10-20 cm thick layer of dust covering a strong ice or perhaps an ice/dust mixture.


Click diagram of Philae to enlarge.

credit image; ESA

Lander Philae was released from Mothership Rosetta at spacecraft time of 08:35 GMT, 12 November 2014;  with confirmation reaching Earth a little over 28 minutes later at, 09:03 GMT.  As soon as Philae was released, MUPUS began observing the comet’s surrounding environment.


Philae first touched-down on Comet 67P/Churyumov-Gerasimenko at 15:34 GMT (with confirmation reaching Earth at 16:03 GMT). However, the harpoons and ice screws did not fire as planned and Philae rebounded, almost like is slow motion, with two more touchdowns; one at spacecraft of 17:25 GMT, and the other at 17:32 GMT.


Part of the MUPUS mission package was contained in the harpoons, and because they did not deploy, some accelerometer and temperature data could not be obtained. Nevertheless, the MUPUS thermal mapper, located on the body of the lander, worked throughout the descent and during all of the 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.


Jörg Knollenberg, the instrument scientist for MUPUS at DLR said, “We think this is either due to radiative transfer of heat to the cold nearby wall seen in the CIVA images or because the probe had been pushed into a cold dust pile,”  

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.


Tilman Spohn, the principal investigator for MUPUS said, “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,”

Combining the results of the thermal mapper with the probe, the team have made the preliminary assessment that the upper layers of the comet’s surface consist of dust of between 10–20 cm thickness, overlaying strong ice or ice and dust mixtures.

At greater depths, the ice likely becomes more porous, due to the overall low density of the nucleus, which is indicated by instruments on the Rosetta orbiter.

Looking to the future, Tilman Spohn says, “MUPUS could be used again if we get enough power. Then we could perform direct observations of the layer that the probe is standing in and see how it evolves as we get closer to the Sun.”


The full analyses of the lander’s multiple touchdowns and the data collected during descent and landings are on-going. Meanwhile the Mothership Rosetta continues its science mission orbiting Comet 67p/G-G, gathering information, and will continue to stay in orbit over the next year as 67P/C-G gets closer to the Sun, and will watch how the comet’s surface and its surrounding environment evolves.



MUPUS stands for;

MUPUS: MUlti-PUrpose Sensors for Surface and Sub-Surface Science (studying the properties of the comet surface and immediate sub-surface)

Development, maintainence and operational of MUPUS

The thermal probe of MUPUS was originally developed at the Institute of Planetology of the University of Münster together with the Space Research Centre in Warsaw and other international partners. It is maintained and operated by an international team led by the DLR Institute of Planetary Research in Berlin.