Interferometric image fusion: interferometry in space

Image fusion and information extraction from multiple spacecraft can occur after each image is sampled and digitized. A more tantalizing, but difficult, approach would be to optically phase multiple spacecraft flying in formation. Phasing of multiple spacecraft allows for coherent addition of imagery resulting in an optical system with a synthetic aperture as large as distance between the spacecraft. Thus, space based optical imaging systems approaching 100´s of meters could theoretically be achieved; ultimately allowing for resolution of the solar disks of stars and resolution of extra-solar planets around these stars. The methods and techniques for systems of this type, as well as a number of optical testbeds for proof of principle and validation of the methods are currently under study at NASA Goddard Space Flight Center. In this work we give an overview of the underlying principles, the technology required and the state of development of the various testbeds involved.