Successful Chinese science satellites launched since 2015 include the Dark Matter Particle Explorer (DAMPE), the Quantum Experiments at Space Scale (QUESS) and the Hard X-ray Modulation Telescope (HXMT). These were under a space science program of the Chinese Academy of Sciences (CAS).

The second phase of the program has now started, Wang Chi, director of the National Space Science Center under the CAS, recently told the first China Space Science Assembly in Xiamen, east China's Fujian Province.

The first mission of the second phase was Taiji-1, China's first satellite to conduct in-orbit experiments on key technologies related to space-based gravitational wave detection, which went into space on Aug. 31, 2019.

The four new missions include the Gravitational Wave Electromagnetic Counterpart All-sky Monitor (GECAM), expected to be launched at the end of 2020, which will search for electromagnetic signals associated with gravitational waves, Wang said.

The Advanced Space-borne Solar Observatory (ASO-S), expected to be launched at the end of 2021, will help scientists understand the solar magnetic fields, flares and coronal mass ejections.

A satellite named Einstein-Probe (EP), tasked with discovering celestial bodies that emit X-rays during fierce changes as well as quiescent black holes with transient high-energy radiation, is expected to be launched at the end of 2022.

The Solar Wind Magnetosphere Ionosphere Link Explorer, or SMILE, is a Sino-European joint mission expected to be launched at the end of 2023. It will focus on the interaction between the solar wind and the earth's magnetosphere.