European PLATO mission to eye a million stars in search for planets

The European Space Agency says it has chosen a space-based observatory to search for planets orbiting alien stars as its third medium-class science mission. The Planetary Transits and Oscillations of stars mission -- PLATO -- was selected by its Science Program Committee for implementation as part of its Cosmic Vision 2015–25 Program, with a launch planned by 2024, the agency said in a release from its Paris headquarters Wednesday. Equipped with 34 separate small telescopes and cameras, PLATO will search for planets around up to a million stars spread over half of the sky, watching for tiny, regular dips in brightness as their planets transit in front of them, temporarily blocking out a small fraction of the starlight. PLATO's mission will have an emphasis on discovering and characterizing planets in the habitable zone of their parent star, the orbital distance from the star where liquid surface water could exist, ESA officials said. "PLATO, with its unique ability to hunt for sun–Earth analogue systems, will build on the expertise accumulated with a number of European missions, including CoRot and Cheops," Alvaro Gimenez, ESA's Director of Science and Robotic Exploration, said. "Its discoveries will help to place our own solar system's architecture in the context of other planetary systems." PLATO will be launched on a Soyuz rocket from Europe's Spaceport in Kourou in French Guiana by 2024 for an initial 6-year mission, ESA officials said.