A New X-ray Astronomy Satellite

On Friday, the Japan Aerospace Exploration Agency (JAXA) will be launching their sixth satellite dedicated to X-ray astronomy, ASTRO-H, from the Tanegashima Space Center in Kagoshima, Japan. The launch is scheduled at 3:45 a.m. EST.

The observatory carries a state-of-the-art instrument and two telescope mirrors built at Goddard Space Flight Center. That instrument is the Soft X-ray Spectrometer which is able to detect individual low-energy x-ray photons. The SXS detector is cooled to 0.05 degrees above absolute zero, and to keep system noise within useful limits, the operating temperature is held constant ±0.000001 degrees. I was the analog electronics engineer for the team that designed the temperature control system for the SXS.astro-h_illo_labels_0

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Image Credit: JAXA

UPDATE—JAXA has announced that the ASTRO-H launch has been postponed because of high winds at the launch facility. The next possible launch date is on Sunday.

Stay tuned.

7 thoughts on “A New X-ray Astronomy Satellite

    • I know, right?!

      Our Gentle Host should be like a Chief Engineer or something. 😉

      Kidding aside… very, very impressive.

    • Well done Mr. Hoge!

      BTW, how do you test such a system here on earth during production? Meaning, how do you create an environment that is cooled to 0.05 degrees above absolute zero?

      • The system uses three adiabatic demagnetization refrigerators to cool in stages from 5 K to 1.3 K to 0.5 K to 0.05 K. During the early phases of the mission, liquid helium will be available as a heat sink. At near vacuum pressures, helium boils at 1.3 K, so the first of the ADR stages won’t be used initially. After the helium boils off, a cryocooler system will provide a 5 K heat sink, and the first ADR will be used. During testing on the ground, liquid helium was used for shakedown testing. At sea level pressure, helium boils at about 4.2 K. Eventually, the entire system was put in a thermal/vacuum chamber that simulated on-orbit conditions.

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