China will launch satellite to search for Earth clones

With 10 to 15 times the strength of NASA's Kepler telescope, the new Chinese satellite will find exoplanets in the habitable zone of a Sun-like star.

After launching rovers to the Moon and Mars and building its own space station, China is heading towards distant star systems. In April, scientists will announce the blueprint for China's first exoplanet detection mission. This mission aims to survey planets outside the solar system, in other regions of the Milky Way, to find Earth-like planets in the habitable zone of Sun-like stars. Astronomers think such a planet (called Earth 2.0) would have the right conditions for liquid water and possibly life.

Simulation of a star system in the Milky Way.

Researchers have found more than 5,000 exoplanets in the Milky Way, mainly through NASA's Kepler space telescope. The Kepler telescope ran for nine years before it ran out of fuel in 2018. Some of these planets are rocky, Earth-like and orbiting small red dwarfs, but none of them fit the definition. about Earth 2.0. With current technology and telescopes, it is very difficult to find signs of small Earth-like planets when their host stars are a million times more massive and billions of times brighter than the Sun, according to Jessie Christiansen, an astrophysicist Literature at the California Institute of Technology's Institute of Exoplanet Science in Pasadena.

China's mission, called Earth 2.0, could change that. The project is in the initial design phase with funding from the Chinese Academy of Sciences. If the design is approved by the panel of experts in June, the mission team will be funded to start building the satellite. They plan to launch the spacecraft with the Long March rocket before the end of 2026.

Satellite Earth 2.0 is designed to carry 7 telescopes to observe the sky for 4 years. The six telescopes will come together to survey the constellation Cygnus-Lyra, the region of the sky that the Kepler telescope has probed, said Jian Ge, astronomer in charge of the Earth 2.0 mission at the Astronomical Observatory. Shanghai under the Chinese Academy of Sciences.

The cluster of telescopes will search for potential targets by detecting small changes in the star's brightness, indicating an exoplanet passing in front of it. Using many small telescopes will give scientists a broader view than using a large telescope like Kepler. Earth 2.0's cluster of six telescopes will observe about 1.2 million stars. At the same time, Earth 2.0 can track many fainter and more distant stars NASA's Transiting Exoplanet Survey Satellite (TESS), which is surveying bright stars close to Earth. "Our satellite is 10 to 15 times more powerful than NASA's Kepler telescope in terms of its ability to survey the sky," Ge said.

The satellite's seventh instrument will be a gravitationally amplified telescope to survey rogue planets that do not orbit any stars and exoplanets as distant from their host star as Neptune. This telescope will focus on the center of the Milky Way. If successful, it will be the first gravitationally amplified telescope in space.

Combining the Earth 2.0 data with the Kepler observations, the team was able to confirm the exoplanets are indeed Earth-like. Ge hopes to find dozens of such planets and publish the data within 1-2 years of launch.