| The Spacecraft The Suzaku spacecraft weighs about 1,600 kg (3500 pounds) and it will be 7.1 meters (23 feet) long after the Extensible Optical Bench is extended in orbit. The five X-ray Telescopes (XRTs) and all the instruments (the X-Ray Spectrometer, the 4 X-ray Imaging Spectrometers, and the Hard X-ray Detector) will point in the same direction. This allows scientists to simultaneously study cosmic X-ray sources using the different capabilities of the various onboard instruments. 
Image at Right: Suzaku will stay in low Earth orbit while it observes X rays from the Universe
Credit: ISAS/JAXA
X-Ray Spectrometer (XRS) The detectors in the X-Ray Spectrometer (XRS) are X-ray microcalorimeters. They work by monitoring the temperature of a tiny piece of silicon, and measuring the temperature rise that results when it absorbs an X-ray photon. As you might imagine, measuring the temperature increase from a single photon is fairly difficult. The detectors need to be kept extremely cold, almost to absolute zero (60 milliKelvin or 0.06 Kelvin, about -273 C, or about -460 F), requiring a complex cryogenic system which includes liquid helium and solid neon. The XRS has a limited life of about 2.5 years before the neon and/or helium runs out. The XRS is special because, for the first time, it will provide both high spectral resolution (measuring small differences in the energies of X-ray photons) and high throughput (measuring lots of X rays) in one instrument. 
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Image at Right: The XRS instrument was built at Goddard Space Flight Center.
Credit: NASA/GSFC
The XRS has been developed by a collaboration of Goddard Space Flight Center and University of Wisconsin in the US; and Institute of Space and Astronautical Science (ISAS) and Tokyo Metropolitan University in Japan.
X-ray Imaging Spectrometer (XIS) 
Image at Right: The XIS instrument was built at MIT, ISAS, and other institutions in Japan.
Credit: ISAS/JAXA
There are 4 X-ray Imaging Spectrometers (XIS), each with a 1024x1024-pixel X-ray-sensitive Charge Coupled Device (a CCD, similar to what's in your digital camera, but sensitive to much more energetic light). The use of CCDs for astronomical X-ray spectroscopy was pioneered by the ASCA mission starting in 1993. The XIS has been developed by a collaboration of the Massachusetts Institute of Technology, ISAS, the University of Kyoto, and the University of Osaka. It was fabricated by MIT's Lincoln Laboratory.
Hard X-ray Detector (HXD) 
Image at Right: The HXD instrument detects higher energy x rays than the XRS or XIS and doesn't require a telescope to focus x rays onto it.
Credit: ISAS/JAXA
The Hard X-ray Detector (HXD) is a non-imaging instrument that is designed to detect high-energy X rays. It is harder to build X-ray mirrors for high-energy X rays, so we use the old-fashioned method of "collimation." Imagine observing a star near bright city lights by looking through a cardboard tube: the tube is a collimator, a device that shields your eye (the detector) from light coming from directions other than the star you are pointing at. In the HXD, the collimator is made of a type of scintillator crystal, and is shaped like a well. (A scintillator is anything that glows when irradiated.) Inside the well, there is a detector of a different type of scintillator crystal. The HXD has 16 identical units made up of these two types of crystals. The collimator crystal may not be able to stop all extraneous X rays, but it will allow you to detect X rays coming in sideways. If you get a signal from the detector crystal, and not from the collimator crystal, the X-ray photon came from the direction of the object you are trying to observe. However, if you get signal from both crystals, then the X ray came from some other direction, and it will be discarded by the on-board computer. Scientists hope that this clever design will allow very sensitive observations for X rays with very high energies. The HXD has been developed jointly by the University of Tokyo and ISAS, with collaborators at the Research Center for Nuclear Physics of Osaka University, the High Energy Accelerator Research Organization (KEK), and Institute of Physical and Chemical Research (RIKEN).
X-Ray Telescope (XRT) Neither XRS nor XIS would be of much use if it weren't for the X-Ray Telescopes (XRTs). There are five XRTs, four of which are in front of the four XIS instruments, the fifth will be in front of the XRS. These telescopes play an important role. Just as an optical telescope collects light so your eye or a CCD camera can process it, the X-Ray Telescopes collect light in the form of X-ray photons, allowing the instruments behind them to process those photons. These telescopes contain about 1400 specially shaped mirrors, nested in about 170 layers. These foils are positioned in the telescope so they focus X rays at the XIS and XRS instruments. Each telescope has a diameter of about 40 cm, and weighs about 20 kg. They are deliberately designed for maximum collecting area (allowing more X-ray photons through) per weight while sacrificing the spatial resolution (image sharpness). 
Image at Right: The 5 X-Ray Telescopes focus incoming x rays onto the XRS and 4 XIS instruments.
Credit: NASA/GSFC
The XRTs on Suzaku were developed by a collaboration of GSFC, ISAS, and the University of Nagoya. The XRTs are the successors to those used on BBXRT instrument (part of the ASTRO-1 Shuttle payload) and on ASCA.
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