After two years of successfully orbiting Comet 67P/Churyumov-Gerasimenko, ESA's Rosetta spacecraft is ready to take its final plunge on September 30.
The comet is now moving further and further from the Sun, so the solar-powered craft is receiving significantly less energy to power itself and its instruments. There were suggestions of sending the probe into hibernation, but after 12 years in space (two years around a dusty comet), it's not clear if the aging spacecraft would wake up again.
It’s not all doom and gloom, though. The final hours of the spacecraft will provide the closest-ever images of a comet as well as the highest-precision measurements of 67P.
“We’re trying to squeeze as many observations in as possible before we run out of solar power,” said Matt Taylor, ESA Rosetta project scientist, in a statement. “September 30 will mark the end of spacecraft operations, but the beginning of the phase where the full focus of the teams will be on science. That is what the Rosetta mission was launched for and we have years of work ahead of us, thoroughly analyzing its data.”
Rosetta will be set on its final course in August with a series of accurate maneuvers that will slowly set it on its final trajectory. The approach has to be slow because the closer it gets, the larger the influence of the comet’s uneven gravity.
The final trajectory change will happen 12 hours before impact, when the probe will be 20 kilometers (12 miles) from Rosetta. Days before, the final instructions will be uploaded, commanding Rosetta to turn off all its instruments on impact.
Its speed on impact will be 1.8 km/h (1.1 mph), which is fairly gentle, although it's unclear if any of the spacecraft will survive intact.
“Although we’ll do the best job possible to keep Rosetta safe until then, we know from our experience of nearly two years at the comet that things may not go quite as we plan and, as always, we have to be prepared for the unexpected,” cautioned Patrick Martin, ESA Rosetta’s mission manager. “This is the ultimate challenge for our teams and for our spacecraft, and it will be a very fitting way to end the incredible and successful Rosetta mission.”
This is the beginning of the end for Rosetta, but more incredible science is coming.