Between a rock and a dark place

A probe that landed on a comet in a first for space exploration has ended up in the shadow of a cliff, about a kilometre from its intended resting place, the European Space Agency said yesterday.

The lander, named Philae, was released from its mother ship Rosetta on Wednesday as it orbited comet 67P/Churyumov-Gerasimenko, in the climax of a 10-year mission for the space agency.

But harpoons to anchor it to the surface failed to deploy and it bounced twice before floating to rest two hours later.

The agency needs to analyse data beamed half a billion kilometres back to Earth to pinpoint its location.

"Where we are is not entirely where we wanted to be," lead lander scientist Jean-Pierre Biebring told a news conference.

The space agency has published pictures of the comet and images of the 100kg lander - virtually weightless on the comet's rocky surface - and said it was operating normally.

"Do not put the emphasis on the failures of the system, it is gorgeous where we are now," Biebring said.

In the shadows, Philae's solar panels, which were meant to power the probe when its batteries run out on Friday, get only an hour-and-a-half of sunlight a day, instead of the expected six to seven hours.

The probe could try to use its landing gear to hop out of the shadows but the space agency will need to know more exactly where it is before attempting the risky manoeuvre, scientists at its space operations centre in Darmstadt, Germany, said.

The lander also appears to have only two of its three feet on the ground, raising questions about whether it can drill without tipping over or pushing itself off into space.

Scientists hope that samples drilled from the comet by Philae will unlock details about how the planets - and possibly even life - evolved. The rock and ice that make up comets preserve ancient organic molecules like a time capsule.

Comets date back to the formation of the solar system some 4.6billion years ago.