The European Space Agency’s Rosetta mission dropped the robot Philae onto Comet 67P in November 2014.
But after a troubled landing and 60 hours of operation, there has largely been radio silence from Philae.
The German Aerospace Center (DLR), which led the consortium behind Philae, said the lander is probably now covered in dust and too cold to function.
“Unfortunately, the probability of Philae re-establishing contact with our team at the DLR Lander Control Center is almost zero, and we will no longer be sending any commands,” said Stephan Ulamec, the lander’s project manager at DLR.
The probe’s historic landing famously happened several times in succession – with its first bounce looping nearly 1km back from the comet’s surface and lasting a remarkable 110 minutes.
When it finally settled, its precise location was unknown but images and other data suggested it was sitting at an awkward angle, in the shade.