Neutron Star Interior Composition Explorer

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Artist concept of NICER aboard the ISS
Mission type Neutron star astrophysics
Operator NASA / GSFC / MIT
Mission duration Planned: 18 months
Spacecraft properties
Launch mass 372 kg (820 lb)[1]
Start of mission
Launch date June 3, 2017, 21:07:38 (2017-06-03UTC21:07:38) UTC[2]
Rocket Falcon 9 Full Thrust
Launch site Kennedy LC-39A
Contractor SpaceX
Orbital parameters
Reference system Geocentric
Regime Low Earth
Inclination 51.6°
Epoch Planned
X-ray Timing Instrument (XTI)
NICER - SEXTANT logo.png
NICER / SEXTANT mission patch

The Neutron star Interior Composition Explorer (NICER) is a 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.[3] 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.[4]


By May 2015, NICER was on track for a 2016 launch, having passed its critical design review and resolved an issue with the power being supplied by the ISS.[5] Following the CRS-7 loss in June 2015, which delayed future missions by several months, NICER was finally launched on June 3, 2017,[2] with the SpaceX CRS-11 ISS resupply mission aboard a Falcon 9 rocket.[6]

Science instrument[edit]

NICER's primary science instrument, called the X-ray Timing Instrument (XTI), is an array of 56 X-ray photon detectors. These detectors record the energies of the collected photons as well as with their time of arrival. A GPS receiver enables accurate timing and positioning measurements.

During each ISS orbit, NICER will observe two to four targets. Gimbaling and a star tracker allow NICER to track specific targets while collecting science data. In order to achieve its science objectives, NICER will take over 15 million seconds of exposures over an 18 month period.[7]

X-ray navigation and communication experiments[edit]

An enhancement to the NICER mission, the Station Explorer for X-ray Timing and Navigation Technology (SEXTANT), will act as a technology demonstrator for X-ray pulsar-based navigation (XNAV) techniques that may one day be used for deep-space navigation.[8]

As part of NICER testing, a rapid-modulation X-ray device was developed called Modulated X-ray Source (MXS), which is being used to create an X-ray communication system (XCOM) demonstration. If approved and installed on the ISS, XCOM will transmit data encoded into X-ray bursts to the NICER platform, which may lead to the development of technologies that allow for gigabit bandwidth communication throughout the Solar System.[9]


 This article incorporates public domain material from websites or documents of the National Aeronautics and Space Administration.

  1. ^ "SpaceX CRS-11 Mission Overview" (PDF). NASA. Retrieved 3 June 2017. 
  2. ^ a b Clark, Stephen (June 3, 2017). "Reused Dragon cargo capsule launched on journey to space station". Spaceflight Now. Retrieved June 3, 2017. 
  3. ^ Gendreau, Keith C.; Arzoumanian, Zaven; Okajima, Takashi (September 2012). "The Neutron star Interior Composition ExploreR (NICER): an Explorer mission of opportunity for soft x-ray timing spectroscopy" (PDF). Proceedings of the SPIE: Space Telescopes and Instrumentation 2012, Ultraviolet to Gamma Ray. 8443. Bibcode:2012SPIE.8443E..13G. doi:10.1117/12.926396. 
  4. ^ Harrington, J. D. (April 5, 2013). "NASA Selects Explorer Investigations for Formulation" (Press release). NASA. Retrieved April 23, 2013. 
  5. ^ Keesey, Lori (May 12, 2015). "NASA's Multi-Purpose NICER/SEXTANT Mission on Track for 2016 Launch". NASA. Retrieved October 27, 2015. 
  6. ^ "NICER Manifested on SpaceX-11 ISS Resupply Flight". NICER News. NASA. December 1, 2015. Retrieved June 14, 2017. Previously scheduled for a December 2016 launch on SpaceX-12, NICER will now fly to the International Space Station with two other payloads on SpaceX Commercial Resupply Services (CRS)-11, in the Dragon vehicle's unpressurized Trunk. 
  7. ^ "NICER: Neutron star Interior Composition Explorer" (PDF). NASAFacts. NASA. Retrieved 14 June 2017. 
  8. ^ Mitchell, Jason W.; Hassouneh, Munther A.; Winternitz, Luke M. B.; Valdez, Jennifer E.; Price, Samuel R.; et al. (January 2015). SEXTANT - Station Explorer for X-ray Timing and Navigation Technology (PDF). AIAA Guidance, Navigation, and Control Conference. January 5–9, 2015. Kissimmee, Florida. GSFC-E-DAA-TN19095; 20150001327. 
  9. ^ Keesey, Lori (November 4, 2016). "NASA’s NavCube Could Support an X-ray Communications Demonstration in Space — A NASA First". NASA. Retrieved November 5, 2016. 

External links[edit]

Media related to NICER at Wikimedia Commons