Neutron Star Interior Composition Explorer
The Neutron star Interior Composition Explorer (NICER) is a future NASA Explorers program Mission of Opportunity dedicated to the study of the extraordinary gravitational, electromagnetic, and nuclear physics environments embodied by neutron stars, exploring the exotic states of matter where density and pressure are higher than in atomic nuclei. NICER will enable rotation-resolved spectroscopy of the thermal and non-thermal emissions of neutron stars in the soft (0.2–12 keV) X-ray band with unprecedented sensitivity, probing interior structure, the origins of dynamic phenomena, and the mechanisms that underlie the most powerful cosmic particle accelerators known. NICER will achieve these goals by deploying, following launch, an X-ray timing and spectroscopy instrument as an attached payload aboard the International Space Station (ISS). NICER was selected by NASA to proceed to formulation phase in April 2013.