The Rosetta spacecraft – which has been moving along in tandem with Comet 67P/Churyumov-Gerasimenko’s since August, 2014 – is scheduled to complete its mission in a controlled descent to the comet’s surface on September 30, 2016.
Wow. It’s sad to see this wonderful mission end. Who can forget the excitement two years ago, when Rosetta arrived at its comet? But now the comet and spacecraft are getting ever-farther from the sun. The craft is heading out towards the orbit of Jupiter and consequently it’s receiving less sunlight. The solar power needed to operate the craft and its instruments is waning, and there’s been a reduction in the bandwidth available to downlink scientific data back to the European Space Agency (ESA), which spearheaded the mission.
Plus … Rosetta and her instruments are aging. The mission launched on March 2, 2004, aboard an Ariane 5 rocket. On its way toward a rendezvous with its comet, Rosetta made four slingshot flybys to boost its speed via gravitational assist — one around Mars and three around Earth. Now Rosetta has been in the harsh environment of space for over 12 years, the last two of which were in the dusty environment of Comet 67P/Churyumov-Gerasimenko in the most volatile part of its orbit, as it swung in near the sun before and after its perihelion on August 13, 2015.
By September 30, 2016, Rosetta will be about 356 million miles (573 million km) from the sun and 447 million miles (720 million km) from Earth.
The one-way signal travel time will be about 40 minutes.
In addition, beginning around October 1, 2016, if the mission were to continue Rosetta’s operators would be facing reduced communications due to a conjunction of the comet and spacecraft. That is, they will be edging into the sun’s glare, as they behind the sun as seen from Earth. ESA said this is another contributing factor to concluding the mission in late September.
ESA said Rosetta’s final hours will be action-packed as the craft descends toward its comet:
[The descent] will enable Rosetta to make many once-in-a-lifetime measurements, including very-high-resolution imaging, boosting Rosetta’s science return with precious close-up data achievable only through such a unique conclusion.
Communications will cease, however, once the orbiter reaches the surface, and its operations will then end.
Bottom line: The Rosetta comet mission will end its mission with a controlled descent to the surface of Comet 67P/Churyumov-Gerasimenko on September 30, 2016.
Deborah Byrd created the EarthSky radio series in 1991 and EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.