Please make a donation to support Gunter's Space Page.
Thank you very much for visiting Gunter's Space Page. I hope that this site is useful and informative for you.
If you appreciate the information provided on this site, please consider supporting my work by making a simple and secure donation via PayPal. Please help to run the website and keep everything free of charge. Thank you very much.


The XARM (X-ray Astronomy Recovery Mission) satellite is a Japanese X-ray observatory, which is to replace partially the lost Astro H (Hitomi) observatory.

XARM will carry replacements for Hitomiís two lower-energy instruments ó the Soft X-ray Imager and the Soft X-ray Spectrometer. The two Hard X-ray Telescopes and imagers will not be replaced.

NASA provides a copy of Astro-H'se High-Resolution Soft X-Ray Spectrometer (SXS), which will probe matter in extreme environments; investigate the nature of dark matter on large scales in the universe; and explore how galaxies and clusters of galaxies form and evolve.

XARM carries following payloads:

  • Soft X-ray Telescope (SXT-S) with Soft X-ray Spectrometer (SXS)
  • Soft X-ray Telescope (SXT-I) with Soft X-ray Imager (SXI)
  • 2 Soft Gamma-ray Detectors (SGD)

The satellite might be used in conjunction with NuSTAR, which can cover the Hard X-ray segment not included in XARM.

In July 2017, the mission was apporoved. A launch is planned for 2021.

Nation: Japan
Type / Application: Astronomy, X-Ray
Operator: JAXA, NASA
Equipment: SXT-S, SXS, SXT-I, SXI, 2 SGD
Power: 2 deployable fixed solar arrays, batteries
Satellite COSPAR Date LS Launch Vehicle Remarks
XARM - 2021


Further Explorer Missions of Opportunity (MoO) and International Missions: