ET design study has been a project of the European Framework Programme (FP7). It has been proposed by 8 European research institutes leader in the gravitational wave experimental research. The project coordination is realized by the European Gravitational Observatory.

The conceptual design study is now concluded but the project is still alive and open to all the scientists interested to the realization of the ET observatory. Currently the European Commission supports the ELiTES project, addressed to the exchange of know-how and researchers between Europe and Japan and focused on the cryogenic technologies for ET and LCGT (now KAGRA).