Satellites and Spacecraft X-ray Astronomy Satellite "ASTRO-H"

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Apr. 21, 2015 Updated

Soft Gamma-ray Detectors (SGDs) installation on ASTRO-H completed

Soft Gamma-ray Detectors (SGDs) installation on ASTRO-H completed

Two Soft Gamma-ray Detectors (SGDs), which successfully went through the thermal vacuum test and the cooling test, were installed onto the ASTRO-H. The photo shows the SGD2 on the ASTRO-H with a debris cover and a radiator. A golden color MLI (multi-layer insulation) will wrap them so that they will not be seen from outside. All the observation instruments are now installed on the ASTRO-H, so it's preparations for launch are turning the final corner. We will work harder to overcome the many...

About X-ray Astronomy Satellite "ASTRO-H"

(Courtesy of Akihiro Ikeshita)

New space image to be elucidated by X-ray astronomy

In the mid-20th century, we became able to observe space through the light of some wave lengths other than visible light through human eyes. Those invisible wave length lights include radio waves, infrared lights, and X rays. As a result, we found that various phenomena were occurring in space where we had believed nothing existed as we had not been able to observe stars until that time. The X ray is a light with a wave length emitted from the extremely high-temperature region of several million to several hundred million degrees Celsius. In such a region, a supernova explosion, black hole, active galactic nucleus, high-temperature plasma between galaxies and other such kinds of phenomena gravely affect star generation and large space structures and their development such as clusters of galaxies. Actually, such a region is not unusual for us. Rather, it is said that 90 percent of general elements on the periodic table that are visible to us, such as a baryon, can be observed only by X ray.

However X rays seldom reach the Earth's surface as they are obstructed by the atmosphere. Japan has been playing a leading role in the field of X-ray astronomy since the dawn of this field by launching satellites namely "HAKUCHO" (CORSA-b), "TENMA" (ASTRO-B), "GINGA" (ASTRO-C), "ASUKA" (ASTRO-D), and "SUZAKU" (ASTRO-EII), which is currently in operation. The ASTRO-H is the sixth X-ray astronomy satellite following these predecessors.

Characteristics of X-ray Astronomy Satellite "ASTRO-H"

Scientific objectives of ASTRO-H

ASTRO-H enables high sensitivity observations of celestial sources across a wide energy range, from X-rays to gamma-rays, bands presenting considerable technical challenges. Thesatellite features cutting-edge instruments; SXS, operated at only 50 mK, is capable of measuring, with unprecedented accuracy, the energy of incoming X-rays. It measures temperature changes in a sensor resulting from absorption of X-ray photons. HXI, operating in the focusing of a Hard X-ray Telescope, will produce the first ever images of the high-energy X-ray universe. SXI, featuring domestically produced X-ray CCDs, will enable us to make wide field X-ray images of the sky with ultra-low noise. The narrowview semi-conductor Compton camera, SGD, revitalizes the field of gamma-ray observations by featuring the greatest sensitivity in this band. The Japanese heritage of successful previous satellites will provide a basis for meeting these challenges.

Mission talk by team leaders

Project Manager Tadayuki Takahashi

Here are messages from Project Managers.