European Space Agency scientists are set to decide whether to try a risky drilling procedure to enable an exploration probe to examine samples from the surface of a comet before its batteries run out.
The probe, released by the Rosetta spacecraft on Wednesday after a 10-year odyssey 500 million km (300 million miles) from Earth, floated away from its planned landing site after harpoons designed to hold it down on the comet failed to deploy.
It is now resting precariously on two out of three legs in the shadow of a cliff on the comet.