Saying Goodbye To ESA’s Rosetta Mission
published during a waning gibbous moon.
Saying Goodbye

Enhanced NAVCAM image of Comet 67P/C-G taken on 27 March 2016, 329 km from the comet nucleus. The scale is 28 m/pixel and the image measures 28.7 km across. Credits: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0

Sadly, after almost two years since its arrival at comet 67P, the Rosetta mission is coming to an end. Rosetta arrived at comet Churyumov/Garasimenko, 67P, or The Rubber Ducky Comet, on August 3, 2014. The spacecraft was the first to orbit a comet. Philae, Rosetta’s counterpart, made history when it became the first spacecraft to land on the nucleus of a comet.

Rosetta and Philae launched from the European Space Agencies satellite space center in French Guiana on March 2, 2004 and the pair travelled for 10 years to chase down 67P, which is travelling at a swift 88,000 miles per hour. Now, the fuel on board is getting lower, and temperatures are dropping as 67P travels back out towards Jupiter, leaving the team to decide how they would formally end their beloved mission.

Philae after being released from Rosetta. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Last year, the team announced that they would likely choose to crash the spacecraft directly onto the surface of the comet, joining Philae in robotic eternal slumber. While it sounds violent and kind of sad, this is actually a surprisingly common method of spacecraft disposal. The current estimated date for impact is September 30, 2016, but they still aren’t sure exactly how it will land or where.

Rosetta’s project scientist, Matt Taylor, told NOW.SPACE, “This phase is the most challenging so far, more challenging than the lander delivery, as we wish to get real close to the comet and not break the spacecraft before we REALLY want to, so we hope to reach down to only a few kilometers from the surface (1-2 km) and then eventually take the plunge in late September.”

Saying Goodbye

OSIRIS Image of the Day Archive. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

There are some benefits to crashing a billion dollar spacecraft.

Currently, Rosetta is orbiting 11 miles above the surface of the comet, taking images, and collecting information about the materials being released from the comet’s coma. While the spacecraft is still in perfect working condition, it receives significantly less sunlight as it travels away from the sun, reducing its solar power capabilities which in turn impact the ability to keep the machinery warm. These drops in temperature would inevitably damage Rosetta’s fragile internal electronics and render the spacecraft useless.

There are some benefits, however, to crashing a billion dollar spacecraft fully loaded with top notch scientific instruments: it’s a great opportunity to do science. “The final plunge will likely only allow a few instruments on (as we will have less power from the sun due to distance), we aim to at least have ROSINA and OSIRIS on, so we can sniff and see to the surface, or as close as we can,” says Taylor.

ROSINA is a combination of two mass spectrometers whose primary goal is to examine the atmosphere of the comet. The OSIRIS instrument is the main camera for the mission. Using both ROSINA and OSIRIS upon the final descent to the surface could help provide some last minute data about chemicals hiding on the comet’s surface. It could also take some more spectacular images. Taylor explains, “We hope to get data right until the end, but as soon as Rosetta makes contact with any part of the comet, that is it. The main driver for the plunge was to get as close to the comet as possible, to get the highest resolution images, and to measure the lowest part of the coma.”

Saying Goodbye

OSIRIS Image of the Day Archive. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

During the final days of the mission, Rosetta will be in a highly elliptical orbit coming as close as a half a mile above the surface, until on the 30th of September, mission control at ESA will give the final command to enter a controlled collision course with 67P. There is still a small chance that the spacecraft could survive the landing, allowing for the collection of more scientific data, but the team at ESA isn’t expecting much.

Their rundown of the landing explains, “Rosetta was not designed for a landing. Even under a slow impact, the very large solar panels may be damaged, and some of the instrument booms sticking out from the body of the spacecraft may buckle or snap off. Under the very low gravity of the comet, the spacecraft may tumble, further damaging it.”


Series of 19 images captured by Rosetta’s OSIRIS camera as the Philae lander descended to the surface of Comet 67P/Churyumov–Gerasimenko on 12 November 2014. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Regardless of whether or not the spacecraft survives its final impact, it has provided some of the most beautiful images from space ever seen and a slew of scientific data sure to keep planetary scientists busy for years. Overall it’s been 20 years of planning with a total of 12 years in space. Thanks to Rosetta, scientists all over the world now have more information about the formation of our solar system and the strange anomalies that can take place far off in the depths of space.

This animation consists of 86 images acquired by Rosetta‘s NavCam as it approached 67P in August 2014. Credit: ESA/Rosetta/NAVCAM