The Advanced Technology Large-Aperture Space Telescope (ATLAST) is an 8 to 16.8-meter (26 to 55-foot) UV-optical-NIR space telescope proposed by Space Telescope Science Institute, the science operations center for the Hubble Space Telescope (HST). If launched, ATLAST would be a replacement and successor for the HST, with the ability to obtain spectroscopic and imaging observations of astronomical objects in the ultraviolet, optical, and infrared wavelengths, but with substantially better resolution than either HST or the planned James Webb Space Telescope (JWST). Like JWST, ATLAST will be launched to the Sun-Earth L2 Lagrange point.