Chinese astronomers set out Xuntian's cosmology goals: percent-level limits on dark energy and dark matter

China Manned Space Agency/Xuntian (CSST) space telescope

A review led by Yan Gong sets out what Xuntian's ten-year imaging and spectroscopic survey should measure. By mapping how matter is spread from small to large scales and how fast the universe has expanded, the team expects percent-level limits on dark energy and dark matter and sharp tests of gravity.

• Methods: weak gravitational lensing, galaxy clustering, galaxy-cluster counts, cosmic voids, Type Ia supernovae and baryon acoustic oscillations.
• Plan: a ten-year wide survey plus a two-year ultra-deep field.
• Published in Science China Physics, Mechanics & Astronomy (2025).