Future of comet probe 'uncertain'

Robot lab Philae drilled into its host comet with just hours of battery left, but may lose power before it can transmit results of a much-anticipated attempt to probe below the surface, mission scientists said.
The European Space Agency (Esa) says the instrument is being deployed to its maximum extent, despite the risk of toppling the lander.
Scientists hope the tool will be able to capture some samples for analysis in the robot's onboard laboratories. If the battery dies, the results may not make it back to Earth.
Philae made history on Wednesday when it was dropped to the surface of 67P by Esa's Rosetta satellite - and has been returning pictures and other scientific data ever since. It covered 6.4 billion km to reach Comet 67P out near the orbit of Jupiter.
It is not known precisely where on the comet the robot is located, but the pictures it has returned indicate it is in the shadow of a cliff.
The limited sunlight the probe receives means its solar panels cannot keep the battery systems properly topped up.
Engineers doubt Philae in its current position can stay powered beyond tomorrow.
The dwindling energy reserves have therefore prompted the mission team to deploy the drill now.
Although the activity is among Philae's key objectives, it is also highly risky, because the torque on the tool could destabilise the delicately placed lander.
The results of the drilling will not now be known until Rosetta comes back around and tries to re-establish the radio on Friday night.
Scientists hope the investigations of the comet can provide fresh insights on the origins of the Solar System. Comets are believed to hold materials that are largely unchanged since the formation of the planets 4.6 billion years ago.