Greetings from the Project Team

Mission of XRISM

The mission of XRISM project is to recover and resume the study of the prime science objective of ASTRO-H "to solve outstanding astrophysical questions with high resolution X-ray spectroscopy" as soon as possible. Through the development of ASTRO-H, we have succesfully proven in orbit the technology behind the ASTRO-H mission including the exquisite performance of the X-ray spectrometer which has a higher resolution than that of conventional X-ray imaging spectrometer by a factor of 30, and the deployment of an extendable optical bench of 12 m long focal length with low thermal distortion. Utilizing these results of the ASTRO-H development, learning from lessons of the project, we are realizing cutting edge science with high reliability in collaboration with NASA, ESA, and institutes in Japan and abroad.

Project Manager (JAXA)

Hironori Maejima, Ph. D.

Opening a new doorway in X-ray Astronomy

Among all branches of astronomy dating back thousands of years, X-ray astronomy is a relatively new field with less than 60 years of research. However, despite such a short history, X-ray astronomy has observed black holes and neutron stars and detected the hot plasma in between galaxies. It is a field which continues to provide new images of the universe, as well as new observational techniques to reveal new information about the universe. The Resolve instrument (X-ray spectrometer) to be included in XRISM is the latest instrument to open up a new era of history. Learning from the sucesses and failures of ASTRO-H, XRISM will open a new doorway for the X-ray astronomy world.

Mission Principal Investigator (JAXA)

Makoto S. Tashiro, Ph. D., professor

Development Plan

The project is progressing to open up a new world of high resolution X-ray spectroscopy in the early 2020s.

  • 2017 project study
  • 2018 start project, basic design/ detailed design
  • 2019 detailed design/ production and test of instruments/ spacecraft assembly
  • 2020 spacecraft assembly/ proto flight test
  • 2021 proto flight test/ launch campaign
  • 2021fiscal year expected to be launched

History of X-ray astronomy spacecraft in Japan

With 40 years of launching X-ray astronomy spacecraft, Japan has been consistently contributing to the world of X-ray astronomy. Observatory instruments with the latest technology have been launched in the past 6 spacecraft, providing new and never before seen views of the universe.


Hakucho (swan in Japanese)

Launched: 1979 / Ended:1985

Japan's first X-ray astronomy spacecraft, named after the black hole "Cygnus X-1". A modulation collimator, invented by Dr. Minoru Oda (the author of the black hole thesis in 1971 and later, Director of ISAS), was loaded onto the satellite, allowing the location of X-ray sources to be determined with high accuracy. A number of new X-ray bursts were found by this spacecraft, and this mission moved Japanese X-ray astronomy to the forefront internationally.


Tenma (Pegasus in Japanese)

Launched: 1983 / Ended:1988

The newly developed gas scintillation proportional counter doubled the possible energy resolution, enabling more detailed spectroscopy of X-ray sources. One of the main outcomes of this was the discovery of X-ray emisson from hot plasma along the Galactic ridge. This emission has been observed by succeeding spacecraft to elucidate the origin and nature of this emission. It remains one of the most important research themes in X-ray astronomy to this day.


Ginga (Galaxy in Japanese)

Launched: 1987 / Ended:1991

New instrumentation included high sensitivity detectors. Major outcomes included the X-ray detection of supernova 1987A shortly after the commencement of observations, and the discovery of many candidate black holes. A full-scale international collaboration begun with this spacecraft to develop the instruments with researchers from all over the world. Dr. Masatoshi Koshiba detected neutrinos from supernova 1987A using Kamiokande in Gifu prefecture, and was later awarded the Nobel Prize in Physics for this discovery.


ASCA (Flying bird)

Launched 1993 / Ended:2001

The first satellite to carry an X-ray telescope and X-ray CCD camera, dramatically improving sensitivity. Major contributions included the detection of general relativistic effects near black holes through observations of active galactic nuclei, providing direct evidence to support the existence of supermassive black holes at the centers of galaxies. International public observations were begun for the first time, and ASCA data has been opened to and used by scientists worldwide, with a number of thesis projects supported.


Suzaku (Legendary bird, the guardian of the universe)

Launched 2005 / Scientific observations ended 2015.

An X-ray telescope with higher sentivitity than ASCA and instruments to cover a wider bandpass. The major contributions of Suzaku were to detect non-equilibrium ionized plasma in supernova remnants, research into cosmic-ray acceleration mechanisms by shock waves, the detection of X-ray reflection nebulae, detection of active galactic nuclei, elucidating the evolution of galaxy clusters by observing the heavy element distribution in their outer regions, and the X-ray emission from magnetars (highly magnetized neutron stars)


Hitomi (Eye pupil in Japanese)

Launched February 2016 / Ended March 2016

Four distinct instruments were included to explore the mysteries of dark matter and the co-evolution of galaxies and black holes, which controls the growth of structure in the universe. The wideband detectors had ten times more sensitivity than before. The mission was terminated only a month after launch due to a mishap; however, Hitomi achieved revolutionary measurements of the speed of plasma in galaxy clusters and the abundance of heavy elements.



XRISM to be launched in Japanese fiscal year 2021

Equipped with an X-ray micro-calorimeter and X-ray CCD camera, identical to those on Hitomi, specializing in soft X-ray imaging spectroscopy. XRISM's aim is to develop the world of high resolution X-ray spectroscopy, the door to which was opened by Hitomi.