Following a 10-year journey through space and 15 months on the surface of comet 67P/Churyumov-Gerasimenko, it’s time to write the obituary for the European Space Agency’s (ESA) Philae probe, after ground controllers gave up trying to re-establish contact with it. Now in eternal hibernation, the small lander had only made intermittent contact with Earth following a problematic landing in November 2014, and has finally been abandoned to the cosmos.
Controlled by scientists at the German Aerospace Center, Philae had accompanied the Rosetta spacecraft, which launched in March 2004 with the objective of studying the composition of comet 67P. Though Philae did achieve the historic feat of becoming the first probe to land on the surface of a comet, a somewhat bumpy landing left it lying on its side in a shaded ditch.
With no light falling on its solar panels, Philae’s batteries lasted just over 60 hours. However, all was not lost, as the probe did manage to complete 80 percent of its planned scientific activities in this time. These included recording detailed images of the comet’s surface, as well as analyzing the chemical composition of gas and dust.
In doing so, it revealed the presence of several nitrogen and carbon compounds that had never previously been detected in comets. It also found traces of organic compounds like formaldehyde that form some of the basic building blocks of life.
However, because of the awkward angle at which it landed, Philae was unable to deploy its drill and collect samples from beneath the comet’s surface.
Seven months after its batteries died, Philae finally woke up, as the comet’s orbit brought it closer to the Sun, activating the probe’s solar panels. However, following an extended period of radio silence, ground controllers say the chances of re-establishing communication are now virtually zero, since it is likely that many of Philae’s components have been destroyed by freezing temperatures.
With 67P/Churyumov-Gerasimenko currently entering the colder part of its orbit, these temperatures are expected to be somewhere around -180 degrees Celsius (-290 degrees Fahrenheit). The fact that the probe is also probably covered in dust by now is another contributing factor to the decision to give up trying to communicate with it.
Because of this, project manager Stephan Ulamec said “It would be very surprising if we received a signal now,” and that his team will “no longer be sending any commands [to the lander].” However, while ESA’s senior science advisor Mark McCaughrean told the BBC that today is a “sad day,” Monica Grady, who helped create some of Philae’s components, told the Guardian that the data it recorded during its short life should provide enough material to keep scientists busy for years to come as they seek to learn more about the nature of comet 67P.