The X-ray Astronomy Satellite "ASTRO-H" is a world-leading, space based observatory in a field that Japan dominates. With the goal of resolving the mystery of space, a Japan-Western international project team, with Japan as the leader, is developing the ASTRO-H mission. The satellite has a total length of 14 meters and weighs 2.7 tons. This is much larger than previous Japanese scientific satellites and its performance will be enormously improved from the currently-operated "SUZAKU" (ASTRO-EII).

The evolution of our Universe from the Big Bang to the present day created massive structures consisting of stars, galaxies and galaxy clusters, and generated the astonishing energy represented by black holes and supernovae explosions. ASTRO-H has unprecedentedly high spectral resolution, coupled with high sensitivity over a very wide range of energies. These outstanding abilities will enable it to reveal the dynamic structures of galaxies and galaxy clusters for the first time ever, as well as conducting research on hidden massive black holes and the unknown nonthermal particle acceleration mechanisms in supernovae remnants.

Human beings live beneath a thick atmosphere, which blocks many wavelengths of light. Up till the last century, Astronomy advanced using only the optical light that human beings can see. In the 20th century, humanity for the first time became able to go to above the atmosphere, into space and for the first time we learned that space is filled with "invisible" light, i.e. X-rays. X-ray observations with space telescopes revealed that space is a bonanza of super hot phenomena of several hundred thousand degrees, which humanity had never expected.

It is currently expected that 80 percent of matter in our Universe is in a high-temperature state that can only be observed by X-rays. To understand the whole picture of space, X-ray observations are an indispensable method along with optical and radio wave observations from the ground. ASTRO-H will lead the world in the field of X-ray observations and create new opportunities in the space science sector.

X-ray astronomy is a very new field of astronomy. The ASTRO-H satellite will be built by employing advanced technologies that we developed ahead of the world. ASTRO-H is equipped with various instruments to capture images of high energy X-rays and Gamma rays. For example, these technologies include: a new generation sensor called a microcalorimeter. Japan developed cryogenic and nanotechnologies to fabricate a "2048-color all natural color image," which is much more advanced than the traditional "64-color image." a "super mirror" focuses high-energy X-rays that were previously impossible to reflect. New high efficiency semiconductor devices were also created through world-class Japanese semiconductor technology. ASTRO-H will stretch out to its full six meter length by using an expandable optical bench and it also employs new satellite architecture that connects the multiple modularized devices through a network.

When ASTRO-H is launched to space, it will transmit to us new discoveries as well as results that we never expected each and every day. There are many hurdles we have to overcome before its completion. I feel we can do anything when I think about the day we will operate this satellite, which is being developed though everyone's cooperative efforts.

(March, 2011 Updated.)