I promised to tell you about focusing optics. Fiona Harrison at Caltech has developed the technology that can focus hard X-rays and soft gamma-rays (20-100 keV) onto imaging detectors. The technology increases the sensitivity for hard X-rays by coating the mirrors with multiple layers of platinum/silicon carbide and tungsten/silicon that increase the reflectivity of the mirror so that it can reflect higher energy levels onto the detector. A team at Goddard built the optics for this telescope. The technology was first tested on a balloon but is now flying on a satellite called NuSTAR. This is the first time that we’ve used these focusing optics technique above the atmosphere.

NuSTAR instrumentation: The artist’s conception illustrates the orientation of the detectors and optics on the satellite. The solar panel on the left provides power to the telescope. The yellow module on the far right contains the new technology optics which consists of two mirrors. These mirrors focus the hard X-rays and soft gamma rays onto the detectors at the other end of the deployable mast. The optics and the detectors must be separated by 10 meters (30 feet). The detectors and optics are launched close together because they just fit in the existing rockets used to launch satellites into space; the mast is extended after launch.
Credit: NASA