Xuntian (which translates to “survey the heavens”) is a Chinese space telescope currently under development. It is also known as the “Chinese Space Station Telescope” and “Chinese Survey Space Telescope” (CSST).
China is building four astronomy research centers to work with the data from CSST.
CSST will collect images in the visible, near infrared, and near ultraviolet ranges. It will have five instruments on board including a Survey Camera. The main focal plane of the camera will have a 2 meter diameter primary mirror and thirty 81-megapixel detectors (2.5 gigapixels total). CSST will have a field of view 350 times larger than the Hubble Space Telescope. The field of view is the area of sky a telescope can see at one time.
The other four instruments on the CSST are designed to observe individual objects or small fields, like mapping star–forming regions of the Milky Way, obtaining instantaneous color of fast varying objects such as comets and spinning asteroids, studying the co-evolution of supermassive black holes in galaxies and star formation in the nearby part of the universe, and direct imaging of exoplanets in the visible spectrum.
The telescope will operate in a LEO altitude similar to the Hubble Space Telescope. The LEO location of the CSST will allow it to take images of 40% of the sky. For comparison, the Webb telescope will be able to take images of 100% of the sky by virtue of being located at the second Lagrange point or L2.
Xuntian is planned for launch in 2024 on a Long March 5B rocket. The telescope will be put into LEO close to the Chinese space station. The telescope will be equipped with a propulsion and navigation system which will allow for periodic docking with the station as required for maintenance, upgrading of scientific instruments, and refueling.
CSST is being designed for an operational lifespan of at least 10 years.
Additional information for the curious
The telescope is approximately 12 m high, the following partial construction photo provides some perspective on its size.