DARMSTADT, Germany (AFP) - Europe's robot probe Philae may not be securely anchored to comet 67P/Churyumov-Gerasimenko after an apparent glitch with its landing harpoons, the European Space Agency (ESA) said Wednesday.
"There are some indications that they might not have been fired, which could mean that we are sitting in soft material and we are not anchored," Philae lander manager Stephan Ulamec told reporters at ground control in Darmstadt, Germany.
"We have to analyse what is the actual situation," he said as jubilation at end of the robot lab's seven-hour descent quickly turned into concern.
"We have to know exactly where we land, how did we land," said Ulamec, adding more should be known in "a few hours".
ESA Operations earlier tweeted that analysis of telemetry data "indicates harpoons did not fire as 1st thought", though it insisted the lander was "in gr8 [GREAT]shape".
"Team looking at refire options," said the message.
The Philae Lander Twitter account added: "I'm on the surface but my harpoons did not fire. My team is hard at work now trying to determine why."
The 100 kilo lander separated from its mothership, Rosetta, Wednesday after a trek lasting a decade and covering 6.5 billion km.
Philae was designed to settle down at a gentle 3.5kmh, firing two harpoons in the hope that the comet's surface - a complete unknown - would give it grip while it conducts an array of scientific experiments.
Watch the video of the Rosetta Mission here.