A probe that has successfully landed on a comet has ended up in the shadow of a cliff, prompting concerns about its ability to recharge its batteries using solar panels.
The Philae lander was released from the Rosetta orbiter circling comet 67P/Churyumov-Gerasimenko on Wednesday but ended up about a kilometre from its intended landing spot after harpoons designed to anchor it to the surface failed to deploy and it bounced twice before floating to rest two hours later.
The landing is the climax of a 10-year mission for the European Space Agency (Esa), which said that the 100kg lander was operating normally though it will need to analyse data beamed half a billion kilometres back to Earth to pinpoint its exact location.
However, Philae's 60-hour battery life will run out sometime today and its solar panels, which are only getting an hour and a half of sunlight a day in the shade rather than the expected six to seven hours, may struggle to power the lander.
"Where we are is not entirely where we wanted to be," lead lander scientist Jean-Pierre Biebring told a news conference. "Do not put the emphasis on the failures of the system, it is gorgeous where we are now.”
Scientists at the Esa's space operations centre in Darmstadt, Germany, said they are considering using the probe’s landing gear to hop out of the shadows, but they need to work out exactly where it is before attempting the risky manoeuvre.
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 Sun's planets – and possibly even life – evolved. The rock and ice that make up comets preserve ancient organic molecules like a time capsule and scientists suspect some of them may have delivered water to Earth when they collided with the planet millions of years ago.