This paper presents a status of the development of the 1 6meter hybrid mirror demonstrator for the Next Generation Space Telescope (NGST) Program. The COl design approach for the NGST program combines the optical performance of glass, with the high specific stiffhess capabilities of composite materials. This structural hybridization significantly reduces the area! density of mirror substrate, compared to state-of-the-art all-glass mirrors, while maintaining operational robustness. The foundation technologies being exploited in the development of the hybrid mirror ( Figure 1) focus upon precision composite materials for cryogenic operation, and non-contact optical processing (ion figuring) of the lightweight mirror surface. The NGST Mirror System Demonstrator (NMSD) has been designed and built by Composite Optics, Inc. (COT) and is being optically processed by REOSC. The mirror is currently being (optically) tested at cryogenic temperatures at the Marshall Space Flight Center (MSFC) X-Ray Calibration Facility (XRCF). This paper summarizes system requirements, design description, sub-component and component demonstration results, and the technology status for the NGST Mirror System Demonstrator (NMSD) program. The sponsors of these efforts are the NASA Marshall and Goddard Space Flight Centers.
Streaked x-ray radiography images of annular patterns in an evolving tantalum oxide foam under the influence of a driven, subsonic radiation wave were obtained on the National Ignition Facility. This is the first successful radiography measurement of the evolution of well-defined foam features under a driven, subsonic wave in the diffusive regime. A continuous record of the evolution was recorded on an x-ray streak camera, using a slot-apertured point-projection backlighter with an 8 ns nickel source (7.9 keV). Radiography images were obtained for four different annular patterns, which were corrected using a source-dependent flat-field image. The evolution of the foam features was well-modeled using the 3D KULL radiation hydrodynamics code. This experimental and modeling platform can be modified for scaled high-energy-density laboratory astrophysics experiments.
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