The European Space Agency will build a telescope to search for habitable planets in other solar systems.
Named Plato (for Planetary Transits and Oscillations of stars), the telescope, foreseen to be launched in 2024, will work similarly to Nasa’s famous and recently retired Kepler telescope, looking for regular dips in brightness of the nearby stars as planets transit in front of them.
The telescope, resembling an insect’s eye, will consist of 34 separate small telescopes, each 12cm in diameter, and cameras to screen about a million stars spread over half of the sky. The spacecraft will be equipped with the largest camera sensor ever flown in space, consisting of 136 charge-coupled devices (CCDs) with a combined area of almost one square metre.
Its field of view will actually be 20 times larger than that of Nasa’s Kepler spacecraft, crippled last year after a reaction wheel failure.
“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,” said Alvaro Giménez, Esa’s director of science and robotic exploration.
“Its discoveries will help to place our own Solar System’s architecture in the context of other planetary systems."
Plato will join the Solar Orbiter and the dark matter studying spacecraft Euclid, which were chosen in 2011 as Esa’s future flagship missions. The planet-hunting telescope has won over an exoplanet characterisation observatory concept, a large observatory for X-ray timing and mission to collect and return a sample from an asteroid.
Through Plato, scientists will try to shed some light on the conditions for planet formation, the emergence of life, and the general working of the Solar System.
It will also investigate seismic activity in the stars, enabling a precise characterisation of the host sun of each planet discovered, including its mass, radius and age.
When coupled with ground-based radial velocity observations, Plato’s measurements will allow a planet’s mass and radius to be calculated, and therefore its density, providing an indication of its composition.
Plato will be launched on a Soyuz rocket from Europe’s Spaceport in Kourou by 2024 for an initial six-year mission and will operate from L2, a virtual point in space one and a half million kilometres beyond Earth as seen from the Sun.
The telescope, expected to cost some £500m, will use input from the recently launched Gaia observer that will provide detailed characteristics of thousands of exoplanet systems. It is expected the overall cost of the mission will reach up to £800m.