Goodbye Rosetta

One of the European Space Agency’s flagship missions reached its grand finale on Friday 30 September 2016. After 20 years in development, a 10-year trip around the Solar System and two years on station at Comet 67P/Churyumov-Gerasimenko, the Rosetta mission drew to a close at 12:19 BST when the spacecraft performed an intentional crash-landing on the comet’s surface.

 

Comet crash! Artist's impression of Rosetta shortly before hitting Comet 67P/Churyumov–Gerasimenko on 30 September 2016. (Image credit: ESA/ATG medialab)

Comet crash! Artist’s impression of Rosetta shortly before hitting Comet 67P/Churyumov–Gerasimenko on 30 September 2016. (Image credit: ESA/ATG medialab)

 

This marked the end of a fantastically successful science campaign aimed at unraveling the mysteries of comets. These objects, which create spectacular apparitions on the night sky as they approach the Sun and grow tails, are thought to represent pristine material left over from the Solar System’s formation. By rendezvousing with one such object and following it through its passage near the Sun, Rosetta told us that’s it’s made of a mixture of ice, rock and dust, including complex organic compounds; how its ices turn into the gas feeding the tail we see at the telescope; and dropped a lander called Philae that became the first human artefact to ever land on a comet. Now, as 67P is receding from the sun there is not enough sunlight and heat to keep Rosetta operating, hence the decision to end the mission. However, the flow of scientific discoveries is not expected to dry up anytime soon. Scientists have barely began to pore over the treasure trove of data beamed back from it and the intrepid Philae over the two years it spend at comet 67P. The adventure of seeking out cometary secrets has only just began.

 

Rosetta's last image of Comet 67P/Churyumov-Gerasimenko, taken with the OSIRIS wide-angle camera shortly before impact, at an estimated altitude of about 20 m above the surface. The initially reported 51 m was based on the predicted impact time. Now that this has been confirmed, and following additional information and timeline reconstruction, the estimated distance is now thought to be around 20 metres, and analysis is ongoing The image scale is about 2 mm/pixel and the image measures about 96 cm across. (Image credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA)

Rosetta’s last image of Comet 67P/Churyumov-Gerasimenko, taken with the OSIRIS wide-angle camera shortly before impact, at an estimated altitude of about 20 m above the surface. The initially reported 51 m was based on the predicted impact time. Now that this has been confirmed, and following additional information and timeline reconstruction, the estimated distance is now thought to be around 20 metres, and analysis is ongoing
The image scale is about 2 mm/pixel and the image measures about 96 cm across. (Image credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA)

 

Apostolos Christou (Image credit: Apostolos Christou/AOP)

Apostolos Christou (Image credit: Apostolos Christou/AOP)

(Article by Apostolos Christou,  Research Astronomer, Armagh Observatory and Planetarium)