NASA actually did do a feasibility study on the Terrestrial Planet Finder (https://en.wikipedia.org/wiki/Terrestrial_Planet_Finder https://en.wikipedia.org/wiki

NASA actually did do a feasibility study on the Terrestrial Planet Finder (https://en.wikipedia.org/wiki/Terrestrial_Planet_Finder https://en.wikipedia.org/wiki/Terrestrial_Planet_Finder) as a space-based telescope to find terrestial planets orbiting other stars, and one of the versions is an infrared interferometer flying in formation in space. Unfortunately, they never followed through with it (I'm guessing due to technical challenges).