Controllers at the European Space Agency said the contacts were briefer than they had hoped, but proved the little robot was in encouragingly good health after its seven-month slumber.
Philae landed on Comet 67P in November and worked for 60 hours before its battery ran flat.
The robot awoke on Saturday because the comet has moved closer to the Sun, and its solar panels can now generate the electricity needed to power up its systems, including the transmitter.
Its mothership Rosetta, the craft that dropped it on to 67P, is still in orbit around the comet, and can relay messages to Earth.
“We had another contact on Sunday night,” explained Paolo Ferri, the head of operations at Esa’s mission control in Darmstadt Germany.
“That’s good, obviously, but we’re still trying to understand why these contacts are so short. Saturday’s was only 85 seconds; these were 10 seconds in duration spread over several minutes.
“It could have something to do with the orientation of Rosetta; it may not be pointing in exactly the right direction.
“But Rosetta is also 200km from the comet, and although the link should be sufficient it is not super-strong, and if you don’t have the correct alignment, you could lose the connection.”
The various science and engineering teams on the mission are now discussing how to improve the situation.
There should be another opportunity for a contact with Philae on Monday as well.
Currently, the comet, Philae and Rosetta are about 305 million km from Earth. Radio messages take 16 minutes to travel across this vast expanse of space.
Philae had been dormant after bouncing into a dark ditch 60 hours after landing.
The resting place had high walls that obscured the Sun and meant that the robot could not charge its batteries.
With 67P sweeping in towards the Sun, these conditions have changed. Philae’s solar panels are now getting longer and more intense exposure to the Sun.
Scientists must hope they will be able to get enough power into the robot to run a swathe of surface experiments in the coming weeks. And it would be the perfect time. 67P is approaching perihelion – its closet point to our star.
The icy body is now throwing off copious amounts of gas and dust. If, as theory holds, comets are leftovers from the formation of the Solar System, then analysis of all this ejected material should yield remarkable insights into the initial conditions that gave rise to the planets.
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