It’s the beginning of a story that draws you in, but it’s the ending that leaves you lingering, forever connected to the characters. At least if it’s a good story. The fairy tale of Rosetta and Philae, the first spacecraft and lander to rendezvous with a comet and travel with it in orbit around the sun, came to a close early Saturday morning (EDT) in a well-crafted ending.
|A mission poster for Rosetta.|
Image Credit: ESA/ATG medialab; Comet image: ESA/Rosetta/NavCam
The characters enthralled the public, with the video series earning Rosetta and Philae hundreds of thousands of Twitter followers. It’s not just a story of effective public engagement though, it’s a story of more than 20 years of amazing science, engineering, and discovery. Approved in 1993, Rosetta was a European Space Agency mission that included contributions from its member states and NASA. It launched in 2004 on a 10-year trip that included flybys of the Sun and Mars and a two-year hibernation, before finally arriving at 67P/Churyumov-Gerasimenko in the middle of 2014.
|An image from the "Once Upon a Time" cartoon series|
Image Credit: ESA
After a few months of data gathering, Philae separated from Rosetta and landed on the comet’s surface in November of 2014. Philae’s rough landing took a toll, but he still sent back the first set of data from a comet’s surface. Rosetta explored the comet from a distance until September 30, 2016, recording its activity and response to the rise in temperature as it approached the sun. She flew through its clouds of dust and took data on its water vapor, chemical composition, gravity field, surface features, and environment. Ever the photographer, she documented the comet from all angles and revealed a surprising shape that is likely the result of a collision of two different comets.
Analyzing the wealth of data will take time—lots of time—but there have already been some important results. One of Rosetta’s primary aims was to study water, given the theory that water on Earth came at least partially by way of a comet. However, an analysis of water on 67P/Churyumov-Gerasimenko shows a very different molecular makeup than water on Earth. This is evidence that asteroids, not comets, may be primarily responsible for our oceans. An analysis of samples collected by Philae during its touchdown show sixteen organic compounds, including four that haven’t been found on a comet before. They don’t indicate the presence of life, but some of them are ingredients for life.
|Rosetta's last image of Comet 67P/Churyumov-Gerasimenko, taken shortly |
before impact, at an estimated altitude of about 20 m above the surface.
Image Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA.