• Closeby Habitable Exoplanet Survey (CHES): an Astrometry Mission for Probing Nearby Habitable Planets

    Subjects: Geosciences >> Space Physics Subjects: Physics >> Geophysics, Astronomy, and Astrophysics Subjects: Astronomy >> Galaxy and Cosmology submitted time 2024-06-02

    Abstract: The Closeby Habitable Exoplanet Survey (CHES) employs state-of-the-art, high-precision astrometry and positioning technology at the microarcsecond level in space. Its primary objective is to conduct a thorough survey of approximately 100 FGK-type stars within the Sun’s proximity (within 10 parsecs), with the goal of detecting potentially habitable Earth-like planets or super-Earths. This pioneering mission involves a detailed census of habitable planets, providing intricate information on their numbers, true masses, and three-dimensional orbits. Notably, CHES marks a historic milestone as the inaugural international space exploration mission exclusively dedicated to the study of terrestrial planets within the nearby habitable zone. CHES’s payload features a cutting-edge optical telescope with a 1.2 m aperture, a field of view measuring 0.44°×0.44°, and a focal length of 36 m. The telescope utilizes a coaxial three-mirror TMA optical imaging system. Impressively, CHES is designed with a positioning measurement accuracy of 1 μas, solidifying its status as the most precise space exploration project globally in terms of positioning accuracy. To achieve the detection objectives of CHES, it is essential to refine and further substantiate the scientific goals through comprehensive argumentation. Overcoming three key technological challenges is crucial: advancing optical systems for large field of view, developing high-quality space telescopes with minimal distortion; breaking through measurement technology for stellar separations at the 10–5 pixel level; and achieving high stability in satellite system attitude control and thermal control precision. CHES stands on the threshold of groundbreaking discoveries, with the exciting prospect of revealing 50 Earth-like planets. This announces a significant leap forward in China’s space science exploration technology.