Revolutionary optical space telescope concepts are described which utilize a set of new technologies that together promise to reduce the total on-orbit spacecraft weight, and cost, by 2-4 orders of magnitude compared to those using current space technologies, yet could be developed and orbited in the 2010-2015 time period. Astronomical telescopes and Earth imaging sensors with 25 - 250 meter diameter apertures are enabled. They use an adaptive piezoelectric primary membrane, unsupported and uninflated, shaped by an electron beam in response to an optical figure sensor; and a secondary correction stage consisting of a liquid crystal spatial light modulator to remove the residual errors, resulting in high quality optical imaging systems. The membrane is folded for launch, and only shaped after attaining final orbit. There is no inflation or other tensioning structure, nor is there any truss structure. All sensor and spacecraft elements are positioned by precision thrusting control in deep space, and in conjunction with a long passive tether if in GEO. The net result is a filled 25 meter diameter filled aperture imaging spacecraft weighing just 260 kg; or a 250 meter diameter sparse aperture imaging spacecraft weighing just 1,600 kg. These technologies enable implementation of apertures so large and lightweight as to simply not be feasible at affordable cost with current or inflatable technologies.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.