Complex sentence: Nuclear Spectroscopic Telescope Array (NuSTAR) is a planned space-based X-ray telescope that will use grazing incidence mirrors to focus high energy X-rays at 6 to 79 keV from astrophysical sources.
Split into simpler sentences: Nuclear Spectroscopic Telescope Array (NuSTAR) is a planned space X-ray telescope. NuSTAR will use grazing incidence mirrors to focus high energy X-rays at 6 to 79 keV from astrophysical sources.