Humans are good at holding out hope and waiting until all potential opportunities are exhausted before giving a project up for dead.
The European Space Agency team behind the Rosetta mission, which included the Rosetta spacecraft taking up orbital residence at a comet and sending a lander down to the comet's surface, has been holding out hope for the Philae lander since July of last year.
The ESA issued a press release on Friday with the title "Rosetta's Lander Faces Eternal Hibernation." It has been seven months since the ill-fated lander last phoned home to Rosetta on July 9, 2015. The lander has been out of touch due to a faulty thruster sending it out of control during its landing on Comet 67P/Churyumov-Gerasimenko's surface in November of 2014.
"The chances for Philae to contact our team at our lander control centre are unfortunately getting close to zero," said Philae project manager Stephan Ulamec. "We are not sending commands any more and it would be very surprising if we were to receive a signal again."
Philae still did most of its job despite the bumpy landing and resulting resting place in an area with too little sunshine to power the lander's solar panels long term.
"About 80 percent of its initial planned scientific activities were completed," the ESA reports. Its list of accomplishments includes taking surface images, looking for organic compounds and studying the comet's environment from up close.
The lander's final resting place on the comet is still not known, though the ESA team continues to comb high-resolution photos looking for it.
Philae may be lost, but the Rosetta spacecraft will continue its work involving comet observations until September. Rosetta's ultimate fate lies with Philae. The orbiting spacecraft will land on the comet's surface at the end of its mission and begin its own eternal hibernation.