Scientists rejoiced when the Philae comet lander woke up and tweeted last month after seven months of sleep. However, that became short-lived because it went silent again. The European Space Agency (ESA) confirmed on Monday that Philae has stopped communicating with them again.
"No contact has been made with Philae since Thursday 9 July. The data acquired at that time are being investigated by the lander team to try to better understand Philae’s situation," ESA wrote in a blog post.
There are different reasons that the scientists are looking at to explain the sudden lack of contact with Philae. One is the slight shift of Philae's position, possibly triggered by a gas emission from the comet 67P/Churyumov–Gerasimenko, which affected its antenna. Another one is the possibility of a malfunction on one of the two transmission units of the lander.
At this point, scientists are uncertain when Philae would contact them again. They are now focused on the analysis and testing of different commands that could be used to restart its operations.
“Philae is obviously still functional, because it sends us data, even if it does so at irregular intervals and at surprising times,” Philae Lander Manager Stephan Ulamec added. “Several times we were afraid that the lander would remain off – but it has repeatedly taught us otherwise."
On a positive note, scientists are amazed that Philae is still fighting for its life and is trying to reach them from time to time. The lander was expected to die on March due to the sun's heat, but it managed to extend its life by hiding in a shady spot.
"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," Laurence O'Rourke, lander system engineer, told CNN. "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."
