The overall objective of the proposal is to design, develop and demonstrate a potentially portable Compton x-ray scatter 3D-imaging system by using specially designed rotationally movable x-ray source and x-ray detector, and the development of a suitable 3D-processing computer model. The proposed rotational configuration will allow the acquisition of multiple projections or images 360?a around the region of interest, probing a conical volume of the object to be interrogated. The NASA application requires a system that can generate 3D images of non-metallic material when access is limited to one side of the material. The objective of this proposal is to demonstrate the feasibility of developing and build a new, practical, potentially portable, battery operated, self-contained Compton x-ray backscatter 3D imaging system by using a specially designed automated rotationally movable x-ray source, a 2D x-ray detector with a highly collimator system and the development of a suitable 3D processing computer model. In the proposed x-ray imaging system, the primary technical advance will be to extend methods that normally supply a 2D projected image through a sheet of material, to a 3D image with more complicated features at different depths, such as voids, cracks, corrosion or delaminations. The portability of the proposed imaging system will allow bringing it to the object to be imaged. Phase 2 will be conducted with a focus on technology transition and an understanding of what it will take to demonstrate and qualify the proposed method in a prototype for use in an actual imaging system and a realistic environment. Also in Phase II, time reduction in setup, data image acquisition, and 3D-image reconstruction analysis will be realized by remote automated control of the operation and movement of a brighter x-ray source and a state-of-the-art digital flat panel detector in conjunction with a highly collimator system.