|Rosetta’s lander Philae is safely on the surface of Comet 67P/Churyumov-Gerasimenko, as these first two CIVA images confirm. One of the lander’s three feet can be seen in the foreground. The image is a two-image mosaic. Credit: ESA|
The European Space Agency's Philae probe that soft-landed on Comet 67P/Churyumov–Gerasimenko last Wednesday has gone into hibernation because the spacecraft's solar panels are not in the correct angle to be adequately charged by the Sun's rays.
The incorrect angle was caused by the failure of the probe's two harpoons to fire and reel the spacecraft into a proper landing position on the comet's surface. Instead, Philae bounced twice after its first touchdown on the near-gravitation-less comet. The first bounce was about 1 kilometer above the comet's surface and downrange from the designated landing site. A second, lesser bounce occurred, again sending it airborne. Philae then came to an uncontrolled rest on the comet with at least one landing foot pointing outward rather than down towards the comet's surface. Further compounding the lack of sunlight exposure was that Philae touched down near a cliff on the comet which casts a shadow on the probe.
However, ESA scientists were able to command the lander to lift its body by about 4 centimeters and rotate about 35 degrees in an attempt to receive more solar energy to help mitigate these landing misfortunes. But as the last science data fed back to Earth, Philae’s power rapidly depleted, ESA reported. For the remainder of the mission, no contact will be possible with Philae unless sufficient sunlight falls on its solar panels to generate enough power to wake it up.
Before Philae went into hibernation, Rosetta, the spacecraft orbiting the comet and acting as a communications relay from Philae to Earth, was able to re-established contact with the probe for about two hours on Friday. This communication was long enough time for the probe to transmit its housekeeping and science date back to Earth.
The Rosetta mission was launched over a decade ago from Europe’s spaceport in Kourou, French Guiana. During this long voyage, Rosetta had to make three gravitational sling shot maneuvers around the Earth and one around Mars to gain enough speed to catch up with Comet 67P/ Churyumov-Gerasimenko.
Rosetta neared the icy comet on August 6, 2014. After several months of maneuvering the spacecraft into a precise orbit around the comet, Rosetta launched its Philae probe on Wednesday at 4:03 a.m. Eastern Standard Time (09:03 GMT).
Rosetta is the first mission ever to orbit a comet’s nucleus and soft-land a probe on its surface. Rosetta will also be the first spacecraft to fly alongside a comet as it heads towards the inner Solar System, observing how a frozen comet is transformed by the warmth of the Sun. By studying the nature of the comet’s dust and gas, scientists hope that the Rosetta mission will help them understand more about the role of comets in the evolution of the Solar System.