Interferometric arrays of many large telescopes will follow the current precursor interferometers. A few dozen telescopes, equipped with adaptive optics for intra and inter-aperture phasing, mobile on a 1 - 10km terrestrial platform, can provide snapshot images having 10-4 to 10-5 arc-second resolution. On visible objects as faint as mv=25, blind phasing is achievable with the help of laser guide stars on each telescope. The corresponding science is particularly rich and relevant to current issues in stellar physics and cosmology. Following the completion and test of a prototype 1.5 meter telescope, specifically designed for a 27-element interferometric array, larger component telescopes of 8 to 10m may become buildable at a sufficiently low cost for affordable arrays. A preliminary design concept is presented.
In space, arrays of free-flying telescopes currently studied by NASA and ESA, can in principle provide a better limiting magnitude and longer baselines, reaching perhaps 100 km. The current pace of space projects however makes it likely that large ground-based interferometers will be in use before space equivalents.
Keywords : telescope array, stellar interferometer, hign-resolution observing, optical interferometric array, spherical telescope