Mission managers at the European Space Agency (ESA) have not had contact with the Philae comet lander in weeks, a gap they were not all that surprised with.

According to CNN, the last time ESA officials heard from Philae was July 9 and the time before that was June 24, a lapse of two weeks. Rosetta, the satellite that dropped Philae onto Comet 67/P-G, is currently orbiting the lander in attempts to find its whereabouts and open a reliable line of communication.

"The profile of how strongly the Sun is falling on which panels has changed from June to July, and this does not seem to be explained by the course of the seasons on the comet alone," Stephan Ulamec, Philae's project manager, said in an ESA blog post.

As the Guardian pointed out, Rosetta is not having the easiest time finding Philae due to space dust making it difficult to maintain a close orbit with the comet. Philae is the first spacecraft to ever land on a comet, but its historic attempt left it in shadow and therefore unable to soak in the sun's rays with its solar panels.

After waking up in June, Philae has made some contact with ground control, but maintaining contact has been difficult.

"It's not over-worrying in the perspective we haven't heard from the lander in a few days," Laurence O'Rourke, a lander system engineer at the ESA, told CNN. "(In one range), we've never received a signal, and this would suggest that this is some sort of surface feature in the way, which is blocking any signal from the lander reaching the orbiter."

Having no previous mission to compare with, O'Rourke indicated the ESA is ultimately pleased with Philae's progress despite the communication difficulties.

"This is not something that was in our plan originally, but being aware of the lander communication issues means that we are able to take steps (like this one) to overcome them and get science irrespective," he told CNN. "If the lander had landed where it was supposed to land in November, it would have lasted until March, because it had no way to cool itself down.

"The fact that it is where it is - in the shade - in some ways keeps it cool. It's created longevity, which is absolutely amazing."