Space agency: Comet lander ends up in cliff shadow

Berlin, Nov 14: A shadow was cast quite literally across Europe's historic mission to land on and explore a comet. Scientists yesterday said the landing craft not only bounced twice, it also came to rest next to a cliff that's blocking sunlight from its solar panels.

The good news is that the lander Philae is stable and in good health: Its scientific instruments have already begun gathering reams of data to send back to Earth, including the first pictures taken from the surface of a comet. The bad news is that its useful lifetime may now be much shorter.

With just a day or two left before the lander's primary battery is exhausted, scientists are considering what acrobatic maneuvers to risk in order to get the solar panels out of the shadows so they can keep Philae going for a few more months.

The first photos revealed the comet's rocky terrain, including one that showed one of the lander's three feet in the corner of the frame. They indicate that Philae's instruments are working properly, said Jean-Pierre Bibring, the lander's lead scientist at the European Space Agency.

Before deciding whether to try to adjust the lander, scientists will spend the next day or two collecting as much data as possible while its primary battery still has energy. The lander's solar panels were designed to provide an extra hour of battery life each day after that, but this may not be possible now.

'We see that we get less solar power than we planned for'

"We see that we get less solar power than we planned for," said Koen Geurts of the lander team. "This, of course, has an impact on our capabilities to conduct science for an extended period of time," he said.

"Unfortunately this is not a situation that we were hoping for." The lander scored a historic first Wednesday, touching down on comet 67P/Churyumov-Gerasimenko after a decade-long, 4 billion-mile (6.4 billion-kilometer) journey through space aboard its mother ship, Rosetta.

The comet is streaking through space at 41,000 mph some 311 million miles from Earth. The landing was beset by a series of problems that began when thrusters meant to push Philae onto the comet failed. Then two harpoons, which should have anchored the lander to the surface, weren't deployed.

This caused the lander to bounce off the comet and drift through the void for two hours before touching down again. After a second smaller bounce, scientists believe it came to rest in a shallow crater on the comet's 2½ mile-wide body, or nucleus.

PTI