GW Observatories

A proposed United States third-generation gravitational-wave observatory with arms up to forty kilometres long — a scaled-up successor to LIGO that, with the Einstein Telescope, would open the distant gravitational-wave universe.

A proposed Japanese space-based gravitational-wave observatory designed for the decihertz band, between the low frequencies LISA will observe and the high frequencies of the ground detectors — a range no other instrument covers.

A proposed European third-generation gravitational-wave observatory, to be built underground in a triangle of ten-kilometre arms. Its far greater sensitivity would detect compact-binary mergers across most of the observable universe.

A German–British gravitational-wave detector near Hannover with 600-metre arms. Smaller than LIGO or Virgo, it works as a technology testbed — pioneering the squeezed-light and other techniques the larger detectors adopt — and observes as part of the international network.

A proposed Chinese space-based gravitational-wave mission, similar in concept to LISA, that would fly a triangle of spacecraft to detect low-frequency gravitational waves from massive black-hole binaries.

A proposed Chinese space-based gravitational-wave detector of three spacecraft in high geocentric orbit, targeting low-frequency sources such as compact binaries in the Milky Way and merging massive black holes.