NASA Joins Rosetta Mission for Most In-depth Look at a Comet Yet

NASA is joining the European Space Agency's Rosetta mission for the most in-depth look yet at one of the least understood objects in the night sky: comets.

Only six have ever been visited by spacecraft, and in each case only during brief, high-speed flyby missions. Early Monday, however, the comet-hunter Rosetta was switched on after nearly three years of hibernation and a decade since its launch. After a check-up, the spacecraft will begin monitoring a comet known as 67P/Churyumov-Gerasimenko while it travels inside the inner solar system and back out again. During the 16-month period, 67P is anticipated to transform from a completely frozen world, to one dominated by surface eruptions and earthquakes.

"We are going to be in the cometary catbird seat on this one," said Claudia Alexander, project scientist for US Rosetta from NASA's Jet Propulsion Laboratory in Pasadena, Calif. "To have an extended presence in the neighborhood of a comet as it goes through so many changes should change our perspective on what it is to be a comet."

NASA contributed three instruments to the mission, including an ultraviolet spectrometer known as Alice, responsible for analyzing gases in the comet's coma and tail and measuring production rates of water and carbon monoxide and dioxide. By hopefully making key measurements of the argon found in its nucleus, Alice could help reveal what the temperature was when the comet's core formed more than 4.6 billion years ago.

NASA also provided the Microwave Instrument for Rosetta Orbiter and the Ion and Electron Sensor in addition to contributing to an instrument known as the Double Focusing Mass Spectrometer.

Of the instruments, Sam Gulkis, a scientist from NASA's Jet Propulsion Laboratory and the principal investigator for the Microwave Instrument for Rosetta Orbiter, said: "They will all work together to create the most complete picture of a comet to date, telling us how the comet works, what it is made of, and what it can tell us about the origins of the solar system."