The Hitomi Mission

(formerly Astro-H)

Astro-H (also known as "NeXT") is a facility-class mission launched on a JAXA H-IIA into low Earth orbit on Feb 17 , 2016 at 5:45 pm JPS from Tanegashima Space Center in Japan. Soon after launch, ASTRO-H was named Hitomi.
Hitomi is the Japan's sixth X-ray astronomy mission, and is primarily developed at the Institute of Space and Astronautical Science of Japan Aerospace Exploration Agency (ISAS/JAXA) in collaboration with U.S. (NASA/GSFC) and Japanese institutions with contributions from the European Space Agency (ESA), the Netherlands Institute for Space Research (SRON), the Canadian Space Agency (CSA) and US and European institutions. On March 27, 2016, JAXA lost contact with the satellite and on April 28 announced to cease the efforts to restore the mission operations. Hitomi collected about one month worth of data with its instruments.

The Hitomi mission objectives are to:

  • Study of the structure of the universe
    • How do black hole develop, and how do they impact the surroundings ?
    • How are galaxy clusters created and how do they evolve ?
    • When were heavy elements in the universe created , and how much ?
  • Study of the physics in extreme conditions
    • What physical phenomena are occurring in extreme conditions with high density and strong magnetic fields?
    • Is space time really distorted near black holes?
    • Where and how are cosmic rays created?

To achieve these objectivies, Hitomi is equipped with four different instruments that together cover a wide energy range 0.3-600 keV. The Soft X-ray Spectrometer (SXS), which combines a lightweight Soft X-ray Telescope paired with a X-ray Calorimeter Spectrometer, provides non-dispersive 7 eV resolution in the 0.3-10 keV bandpass with a field of view of about 3 arcmin. Three additional scientific instruments extend the bandpass to produce an observatory with extraordinary new capabilities. The Soft X-ray Imager (SXI) expands the field of view with a new generation CCD camera in the energy range of 0.5-12 keV at the focus of the second lightweights Soft X-ray Telescope; the Hard X-ray Imager (HXI, two units) performs sensitive imaging spectroscopy in the 5-80 keV band; the non-imaging Soft Gamma-ray Detector (SGD, two units) extends Hitomi’s energy band to 600 keV.

NASA/GSFC developped the SXS detector and many of its subsystems together with the Soft X-ray Telescopes. NASA/GSFC has also responsibility for the Science Data Center charter to delevelop the analysis software for all instruments, the data processing pipeline as well as the Guest Observer Facility in support of the Hitomi Guest Observer Program. Due to the cessation of Hitomi operation the GO program has been cancelled.

Hitomi in flight

Latest News

Apr 28, 2016

JAXA ceases Hitomi recovery operations. See press release

Mar 28, 2016

JAXA update on Hitomi status

Mar 27, 2016

Hitomi communication failure. See press release

Feb 29, 2016 - Hitomi completed the critical operation phase successully !

See JAXA press release

24 Feb 2016

The SXS instrument successfully achieved 50 mK operation. The detector system noise looks as expected and the SXS is ready for test observations.

21 Feb 2016

The SXS team successfully performed an aliveness test on the first and second stage ADR's. This included activating the heat switch heaters and applying the nominal 2 amp to each of the salt pill magnets. This indicates that the ADR system is ready to be operated to 50 mK.

Mission Diary

Hitomi Diary


This page is intended for members of the scientific community. For members of the general public, or those interested in general astronomy/astrophysics information please go to our Education and Public Outreach site.


If you have any questions concerning Hitomi, visit the Feedback form.