The Earth Observing-1 (EO-1) mission, as part of the New Millennium Program (NMP), developed and validated a number of instrument and spacecraft bus breakthrough technologies designed to enable the development of future earth imaging observatories that will have a significant increase in performance while also having reduced cost and mass. More specifically, EO-1 has validated a multispectral instrument that is a significant improvement over the Landsat 7 ETM instrument; has validated a hyperspectral land imaging instrument and the unique science that can be performed with hyperspectral data; and has validated the ability of a low-spatial/high-spectral resolution imager that can correct systematic errors in the apparent surface reflectances caused by atmospheric effects, primarily water vapor. The breakthrough spacecraft bus technologies that were validated have been made available for future missions.