NuSTAR is the NASA mission that launched the first focusing hard X-ray space observatory.
The Nuclear Spectroscopic Telescope Array launched on June 13, 2012, from Kwajalein Atoll. Its telescope uses nested grazing-incidence mirrors and a long deployable mast to focus high-energy X-rays onto detectors.
NuSTAR was designed to observe black holes, neutron stars, supernova remnants, and other energetic sources. By focusing hard X-rays instead of merely recording them across a wide field, it can produce sharper images and more sensitive measurements in that energy range.
NuSTAR is often confused with Chandra, which is NASA’s major high-resolution X-ray observatory but launched in 1999 and works across a different, broader X-ray range. NuSTAR’s distinctive achievement is focusing hard X-rays, allowing astronomers to study obscured black holes and radioactive material in stellar explosions.