Philae landed on Comet 67P after a 10-year journey
The European Space Agency (Esa) says its comet lander, Philae, has woken up and contacted Earth.
Philae, the first spacecraft to land on a comet, was dropped on to the surface of Comet 67P by its mothership, Rosetta, last November.
It worked for 60 hours before its solar-powered battery ran flat.
The comet has since moved nearer to the sun and Philae has enough power to work again, says the BBC's science correspondent Jonathan Amos.
Jean-Yves Le Gall, the president of France's CNES space agency, told AFP that Philae had sent signals for a period of two minutes "as well as 40 seconds worth of data".
Philae is designed to analyse ice and rock on the comet.
The Rosetta probe took 10 years to reach the comet, and the lander - about the size of a washing-machine - bounced at least a kilometre when it touched down.
Its exact location on the comet has since been a mystery.
However, Esa said on Thursday that it might have located it from images and other data from the mothership.