Nuclear Spectroscopic Telescope Array (NuSTAR) is a planned space-based X-ray telescope that will use a Wolter telescope to focus high energy X-rays at 5 to 80 keV from astrophysical sources, especially for nuclear spectroscopy. It is the eleventh mission of the NASA Small Explorer satellite program (SMEX-11) and the first space-based direct-imaging X-ray telescope at energies beyond those of the Chandra X-ray Observatory and XMM-Newton. The planned mission launch scheduled for 21 March 2012 was postponed by software issues with the launch vehicle. Its primary scientific goals are to conduct a

deep survey for black holes a billion times more massive than our sun, understand how particles are accelerated to within a fraction of a percent of the speed of light in active galaxies, and understand how the elements are created in the explosions of massive stars by imaging the remains, which are called supernova remnants.The principal investigator is Fiona Harrison of the California Institute of Technology (Caltech). Other major partners include the Jet Propulsion Laboratory (JPL), University of California at Berkeley, Danish Technical University (DTU), Columbia University, Goddard Space Flight Center, Stanford University, University of California, Santa Cruz, Sonoma State University, Lawrence Livermore National Laboratory, and the Italian Space Agency (ASI). NuSTAR’s major industrial partners include Orbital Sciences Corporation and ATK Space Systems-Goleta. NuSTAR employs two grazing incidence focusing optics each of which consists of 133 concentric shells. The optics used were coated by DTU Space in Copenhagen and assembled at the Nevis Laboratories of Columbia University. NuSTAR’s predecessor, the High Energy Focusing Telescope (HEFT), was a balloon-borne version that carried telescopes and detectors constructed using similar technologies.