The Neutron Star Interior Composition ExploreR (NICER) is a

NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ...

telescope on the

International Space Station The International Space Station (ISS) is the largest modular space station currently in low Earth orbit. It is a multinational collaborative project involving five participating space agencies: NASA (United States), Roscosmos (Russia), JAXA ...

, designed and dedicated to the study of the extraordinary gravitational, electromagnetic, and nuclear physics environments embodied by

neutron star A neutron star is the collapsed core of a massive supergiant star, which had a total mass of between 10 and 25 solar masses, possibly more if the star was especially metal-rich. Except for black holes and some hypothetical objects (e.g. white ...

s, exploring the exotic states of matter where density and pressure are higher than in

atomic nuclei The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on the 1909 Geiger–Marsden gold foil experiment. After the discovery of the neutron ...

. As part of NASA's

Explorer program The Explorers program is a NASA exploration program that provides flight opportunities for physics, geophysics, heliophysics, and astrophysics investigations from space. Launched in 1958, Explorer 1 was the first spacecraft of the United Stat ...

, ''NICER'' enabled rotation-resolved

spectroscopy Spectroscopy is the field of study that measures and interprets the electromagnetic spectra that result from the interaction between electromagnetic radiation and matter as a function of the wavelength or frequency of the radiation. Matter wa ...

of the thermal and non-thermal emissions of neutron stars in the

soft X-ray An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 Picometre, picometers to 10 Nanometre, nanometers, corresponding to frequency, ...

(0.2–12

keV Kev can refer to: Given name * Kev Adams, French comedian, actor, screenwriter and film producer born Kevin Smadja in 1991 * Kevin Kev Carmody (born 1946), Indigenous Australian singer-songwriter * Kev Coghlan (born 1988), Scottish Grand Prix motor ...

) 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'' achieved these goals by deploying, following the launch, and activation of

X-ray An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...

timing and spectroscopy instruments. ''NICER'' was selected by NASA to proceed to formulation phase in April 2013. NICER-SEXTANT uses the same instrument to test X-ray timing for positioning and navigation, and MXS is a test of X-ray timing communication. In January 2018, X-ray navigation was demonstrated using NICER on ISS.

Launch

By May 2015, NICER was on track for a 2016 launch, having passed its

critical design review In the United States military integrated acquisition lifecycle the Technical section has multiple acquisition "Technical Reviews". Technical reviews and audits assist the acquisition and the number and types are tailored to the acquisition. Over ...

(CDR) and resolved an issue with the power being supplied by the ISS. Following the loss of

SpaceX CRS-7 SpaceX CRS-7, also known as SpX-7, was a private American Commercial Resupply Service mission to the International Space Station, contracted to NASA, which launched and failed on June 28, 2015. It disintegrated 139 seconds into the flight aft ...

in June 2015, which delayed future missions by several months, NICER was finally launched on 3 June 2017, with the

SpaceX CRS-11 SpaceX CRS-11, also known as SpX-11, was a Commercial Resupply Service mission to the International Space Station, launched successfully on 3 June 2017. The mission was contracted by NASA and was flown by SpaceX. The mission utilized a Falcon ...

ISS resupply mission aboard a Falcon 9 v1.2 launch vehicle.

Science instrument

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

Global Positioning System The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite sy ...

(GPS) receiver enables accurate timing and positioning measurements. X-ray photons can be time-tagged with a precision of less than 300 ns. During each ISS orbit, NICER will observe two to four targets. Gimbaling and a

star tracker A star tracker is an optical device that measures the positions of stars using photocells or a camera. As the positions of many stars have been measured by astronomers to a high degree of accuracy, a star tracker on a satellite or spacecraft may ...

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.

X-ray navigation and communication experiments

An enhancement to the ''NICER'' mission, the

Station Explorer for X-ray Timing and Navigation Technology X-ray pulsar-based navigation and timing (XNAV) or simply pulsar navigation is a navigation technique whereby the periodic X-ray signals emitted from pulsars are used to determine the location of a vehicle, such as a spacecraft in deep space. A ve ...

(SEXTANT), will act as a technology demonstrator for

X-ray pulsar-based navigation X-ray pulsar-based navigation and timing (XNAV) or simply pulsar navigation is a navigation technique whereby the periodic X-ray signals emitted from X-ray pulsar, pulsars are used to determine the location of a vehicle, such as a spacecraft in de ...

(XNAV) techniques that may one day be used for deep-space navigation.

XCOM

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. the XCOM test is scheduled for spring 2019. XCOM (inc MXS) was delivered to the ISS in May 2019.''X-ray communications experiment delivered to space station'' May 2019
/ref> Once the test was complete XCOM and the STP-H6 payload malfunctioned in September 2021. It was removed in November 2021 and disposed of on

Cygnus NG-16 Cygnus NG-16, previously known as Cygnus OA-16, was the sixteenth flight of the Northrop Grumman robotic resupply spacecraft Cygnus and its fifteenth flight to the International Space Station (ISS) under the Commercial Resupply Services (CRS-2 ...

Selected results

In May 2018, NICER discovered an

X-ray pulsar X-ray pulsars or accretion-powered pulsars are a class of astronomical objects that are X-ray sources displaying strict periodic variations in X-ray intensity. The X-ray periods range from as little as a fraction of a second to as much as several m ...

in the fastest stellar orbit yet discovered. The pulsar and its companion star were found to orbit each other every 38 minutes. On 21 August 2019 (UTC; 20 August in the U.S.), NICER spotted the brightest X-ray burst so far observed.NICER Telescope Spots Brightest X-Ray Burst Ever Observed
/ref> It came from the neutron star

SAX J1808.4−3658 The first accreting millisecond pulsar discovered in 1998 by the Italian-Dutch BeppoSAX satellite, SAX J1808.4−3658 revealed X-ray pulsations at the 401 Hz neutron star spin frequency when it was observed during a subsequent outburst in 19 ...

about 11,000 light-years from Earth in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

Sagittarius.

Gallery

KSC-20170603-PH AWG06 0008 (35119281635, cropped).jpg, Launch of CRS-11 with NICER aboard Nicer-extraction-loop 0.gif, NICER extracted from Dragon's trunk at ISS Neutron star Interior Composition Explorer (NICER) - 34718447596.jpg, Array of X-ray lenses NICER graphic labeled.png, Labeled diagram of NICER

References

External links

''NICER'' website
by NASA's Goddard Space Flight Center
''NICER'' website
at nasa.gov

{{Orbital launches in 2017 Components of the International Space Station Explorers Program International Space Station experiments Neutron stars Piggyback mission Space telescopes SpaceX payloads contracted by NASA X-ray telescopes 2017 in spaceflight