TianQin

TianQin is a proposed Chinese space mission to detect gravitational waves by measuring the distance between three spacecraft using laser interferometry. It is similar to the ESA LISA proposal. Three probes in Earth orbit, placed in a triangle spaced on the order of 100,000 kilometers from each other, would continually measure the distances between them, sensing changes to these distances resulting from gravitational waves. A ~2035 launch is envisioned. The three would host three Michelson interferometers with the arms much longer than those of LIGO, which would be sensitive to a considerably lower GW frequency (0.0001 to 0.1 Hz), such as would be generated by two bodies with an orbital period in the range of 10 to 10,000 seconds.

TianQin-1 is a spacecraft launched in 2019 that tested some of the necessary technology.