The Rosetta spacecraft has caught up with comet 67P/Churyumov–Gerasimenko.
The spacecraft has been chasing the comet for 10 years, and on August 6, the European Space Agency (ESA) released detailed images and data showing that the probe had come within 100 kilometers of the space rock and is ready to enter into orbit around it. The meeting marks the closest a spacecraft has come to a comet without slamming into it and could reveal whether the space rocks ferried water and other ingredients for life to Earth billions of years ago.
The Rosetta team plans to map the core of the comet, sniff out the elements and molecules floating around it and harpoon a lander onto its surface. In about a year, the mission will give astronomers a ringside seat as the comet gets close to the sun, said Rosetta mission scientist Matt Taylor during an August 6 press conference in Darmstadt, Germany.
Astronomers are particularly interested in watching what happens to the comet’s water during the rock’s journey into the inner solar system. Doing so may divulge whether comets could have brought water to the inner solar system. The mission may even help astronomers determine whether relatively small, rocky worlds with as much water as Earth are the norm or flukes in the creation of planets around stars, said Edward Young a geochemist at the University of California, Los Angeles, who was not involved with the mission.
Hydrogen and oxygen isotopes, versions of the elements that vary slightly in mass, are useful for tracing the origins of water on comets. But “there are no oxygen isotope data from comets at all,” Young said. “Rosetta will change this.”
Scientists will also be combing Rosetta’s data for signs of amino acids, the building blocks of life, which have been found on another comet (SN: 09/12/09, p. 8).
“We have this crazy, bonkers, gold-medal-winning comet to play with for the next year and a half,” said ESA scientist Mark McCaughrean at the press conference. There’s definitely more to come.