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Farewell, Rosetta comet mission

Rosetta and its instruments have been in harsh outer space for 12 years, the last 2 of which have been in the dusty realm of a comet near the sun.

Rosetta spacecraft in early 2016, leaving the inner solar system. Image via Where is Rosetta?

View larger. | See the red arced line, top of image? It’s a depiction of the Rosetta spacecraft in early 2016, leaving the inner solar system. Image via Where is Rosetta?

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.

Before the Rosetta spacecraft mission, who knew comets looked like this? Four-image Rosetta NAVCAM mosaic, using images taken on September 19, 2014 when the spacecraft was 17.8 miles (28.6 km) from Comet 67P/Churyumov-Gerasimenko.

Before the Rosetta spacecraft mission, who knew comets looked like this? Four-image Rosetta NAVCAM mosaic, using images taken on September 19, 2014 when the spacecraft was 17.8 miles (28.6 km) from Comet 67P/Churyumov-Gerasimenko, via ESA.

Location of Rosetta with respect to the sun and several planets on September 30, 2016, the day of its planned controlled descent to the comet's surface and the end of the mission. Image via ESA.

View larger. | Rosetta’s location on September 30, 2016, the day of its planned controlled descent to surface of the comet it’s shadowed since August, 2014. The descent marks the end of the Rosetta mission. Image via ESA.

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.

Farewell, Rosetta!

Read more from ESA about the grand finale of the Rosetta mission

Via ESA/Rosetta/Philae/CIVA.

Rosetta spacecraft ‘selfie’ with comet 67P/Churyumov–Gerasimenko, imaged Sunday, September 7, 2014. Image via ESA/Rosetta/Philae/CIVA.

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

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