Comet probe Philae has started drilling into the surface of the 2.5-mile rugged lump of ice and dust on which it made a historic landing on Wednesday.
But whether enough power remains in the craft's depleting batteries to obtain scientific data from the samples is an unanswered question.
Philae is believed to be tilted to one side in the shadow of a crater wall. It is not receiving enough light to recharge its batteries using electricity generated by its solar panels.
With less than 24 hours before the European Space Agency (ESA) craft's primary battery power runs out, scientists are actively considering taking a last-ditch gamble and "hopping" the lander to a sunnier spot.
In the ultra-low gravity, it might be possible to jump the probe with its landing gear and shift the craft by activating moving parts linked to its instruments.
Using the drill risked destabilising the probe, but held out the promise of delivering valuable science.
ESA project manager Philippe Gaudon said Philae had successfully deployed its drill and bored 25cm into the surface of comet 67P/Churyumov-Gerasimenko.
"So the mechanism has worked, but unfortunately we have lost the link and we have no more data," he said.
Philae lander manager Dr Stephan Ulamec said it was not known whether there would be enough battery power to restore the communications link.