Comet lander’s exploration cut short
Despite rough touchdown, Philae able to collect some data
![Philae images of comet 67P](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2014/11/rosetta_15159097484_159dbc19ea_o_free.jpg?fit=860%2C460&ssl=1)
FINAL RESTING PLACE The first two images from the comet’s surface, combined in this mosaic, suggest Philae landed at the base of a cliff. One of the lander’s feet is seen in the foreground.
CIVA/PHILAE/ROSETTA/ESA
On November 12, a robot called Philae fell from its mother ship Rosetta onto comet 67P/Churyumov–Gerasimenko, touching down not once but three times. Philae’s final resting place, however, put it in a tough spot — in a crevice, in the shadow of a cliff, with two legs on the ground and one in space.
The precarious position wasn’t exactly what mission scientists from the European Space Agency had planned for with the first ever comet landing (SN: 11/1/14, p. 22). Resting on two legs, rather than three, raised concerns about whether all of Philae’s instruments would work correctly. Worse, the cliff’s shadow also blocked solar panels from harvesting enough sunlight to recharge Philae’s batteries, leaving the lander with only about 50 hours of power to explore its new home. Mission scientists were left scrambling to wring as many details as possible about the comet before the lander and its 10 instruments went into hibernation on November 15.
One of Philae’s instruments revealed that it had gotten a whiff of carbon- and hydrogen-rich organic compounds. Another instrument on the lander provided the first high-resolution image of the comet’s surface, released within hours of Philae’s settling onto 67P. Taken from a height of only 3 kilometers, the photo showed that the dusty surface is covered with steep cliffs, boulders and other debris.
In the final hours of Philae’s battery life, the scientists took risks, programming the lander to hammer into the comet’s surface. The hammer penetrated only 10 to 20 centimeters before hitting a hard wall of material, hinting that 67P’s surface is a rigid, possibly icy, layer beneath just centimeters of dust.