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ASTRO-H mission graphic

Phase: Development

Launch Date: 2016

Mission Project Home Page -

Program(s):Astrophysics Explorers, Explorers, Missions of Opportunity

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ASTRO-H (formerly known as NeXT) is a powerful orbiting observatory being developed by the Japan Aerospace Exploration Agency (JAXA) for studying extremely energetic processes in the universe. NASA and the JAXA/Institute of Space and Astronautical Science have teamed up to develop a high resolution “Soft X-Ray Spectrometer” (SXS) for ASTRO-H. SXS, with its unprecedented sensitivity for high-resolution x-ray spectroscopy, will perform a wide variety of breakthrough science investigations directly aligned with NASA goals. SXS will test theories of structure formation by measuring the velocity field of x-ray-emitting gas in clusters of galaxies and the energy output from the jets and winds of active galaxies. SXS will accurately measure metal abundances in the oldest galaxies, providing unique information about the origin of the elements. SXS will observe matter in extreme gravitational fields obtaining time-resolved spectra from material approaching the event horizon of a black hole. SXS will determine the chemical abundances and velocity structure in Galactic Type Ia supernova remnants to provide insight into the explosion mechanism.

To accomplish these investigations, the SXS uses a state-of-the-art x-ray calorimeter spectrometer at the focus of a high-throughput x-ray telescope. The x-ray calorimeter is a low-temperature sensor that measures the energy of each x-ray photon as heat with extraordinary precision, and allows high-resolution spectra to be obtained from extended sources without degradation. The instrument utilizes a multi-stage cooling system that will maintain the ultra-low temperature of the calorimeter array for more than 3 years in space. X-rays are focused onto the array of calorimeters by a highly efficient, grazing-incidence x-ray mirror that provides large collecting area.

The NASA contribution to ASTRO-H was built at the NASA Goddard Spaceflight Center in collaboration with the University of Wisconsin. All NASA provided hardware has now been installed on the JAXA spacecraft and is undergoing the spacecraft testing process.

ASTRO-H will be launched into low-Earth orbit from the Tanegashima Space Center, Japan, by a JAXA H-IIA rocket.

Last Updated: May 26, 2015

Related Links
  • JAXA Astro-H Website -