The Neutron star Interior Composition ExploreR Mission

The Neutron star Interior Composition ExploreR (NICER) is an approved NASA Explorer Mission of Opportunity dedicated to the study of the extraordinary gravitational, electromagnetic, and nuclear-physics environments embodied by neutron stars. NICER will explore the exotic states of matter inside these stars, where density and pressure are higher than in atomic nuclei, confronting theory with unique observational constraints. 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 achieves these goals by deploying, following launch in late 2016, an X-ray timing and spectroscopy instrument as an attached payload aboard the International Space Station (ISS). Grazing-incidence optics coupled with silicon drift detectors, actively pointed for a full hemisphere of sky coverage, will provide photon-counting spectroscopy and timing registered to GPS time and position, with high throughput and relatively low background.

In addition to advancing a vital multi-wavelength approach to neutron star studies through coordination with radio and γ-ray observations, NICER will provide a rapid-response capability for targeting of transients, continuity in X-ray timing astrophysics investigations post-RXTE through a proposed Guest Observer program, and new discovery space in soft X-ray timing science.

Simulated NICER countrates and spectra can be derived using the WebPIMMS and WebSPEC tools.

A 12-slide overview of NICER science is available here.

More NICER documentation and publications.

If you would like to receive email about NICER developments, please subscribe to the NICER-announce email list

For those interested in general astronomy/astrophysics information please go to the Education and Public Outreach site.

Artist concept of NICER

Latest News
  • NICER Blanketeer Featured on CBSnews (06 Jul 2015)
    Paula Cain, who makes the blanket which will protect NICER, was featured on
  • NICER Project Systems Engineer Featured on (06 Jul 2015)
    Charles Baker, the Project Systems Engineer for NICER, was interviewed on
  • NICER Passes Critical Design Review (19 Sep 2014)
    NICER unanimously passed its CDR "with flying colors".
  • NICER at the HEAD Meeting (17 Aug 2014)
    The NICER Special Session at the 2014 meeting of the High Energy Astrophysics Division (HEAD) of the American Astronomical Society will be held on Wednesday, August 20, at 1:30 pm in the Great Lakes Grand Ballroom of the Westin Michigan Avenue hotel in Chicago. Please join us!
  • NICER Critical Design Review (16 Aug 2014)
    NICER's next step towards launch, the Critical Design Review, is planned for September 2014. NICER remains on-track for launch on the SpaceX-12 ISS resupply flight currently scheduled for October 2016.