[Project Topics] ASTRO-H Press Kit

As the launch day approaches, JAXA has released the press kit for the X-ray Astronomy Satellite “ASTRO-H”. It covers ASTRO-H’s satellite and　 mission overview, scientific missions, and observation instruments. Please have a look.

Aiming at the launch and success of the mission, for some years the Astro-H team members have been hard at work at research and development, making steady progress. They have faced many tough obstacles along this long road. They have had many moments of success.
This diary is an introduction to the daily work life — and to the excitements — of these members.

On the day marking exactly one month to launch, the ASTRO-H spacecraft was exhibited to the public at the Tanegashima Space Center. Many questions were asked both about the science goals of ASTRO-H and about its engineering.

The new generation X-ray astronomy satellite ASTRO-H is set for launch on February 12 (Fri.), by the H-IIA Launch Vehicle No. 30 from the Tanegashima Space Center.

JAXA will broadcast a live launch report on the launch day. We will announce more details later. Please look forward to the launch!

The X-ray Astronomy Satellite “ASTRO-H” was revealed to the media on Nov. 27 at the Tsukuba Space Center.
The ASTRO-H is an astronomy satellite to elucidate the structure of space and its evolution through studying high-temperature and high-energy celestial bodies, such as black holes, supernova remnants, and galaxy clusters by X-rays and gamma-rays.
X-rays and gamma-rays from space are absorbed in the Earth’s atmosphere, thus they cannot be observed on the Earth. Therefore observation in space is necessary.
The ASTRO-H was developed as a successor to the Suzaku, also an X-ray astronomy satellite. The ASTRO-H is a flagship mission of X-ray astronomy with the participation of over 200 researchers in its development from various domestic and international universities and research institutions including JAXA and NASA. Four new observation systems developed based on broad-scale international cooperation are installed on the ASTRO-H, hence, compared to the Suzaku, it will be able to perform spectroscopic observations on celestial bodies 10 times to 100 times darker than what the Suzaku was capable of doing.

The sinusoidal vibration test of the X-ray astronomy satellite “ASTRO-H” was held between Aug. 29 and Oct. 2 at the Tsukuba Space Center. The sinusoidal vibration test aims at two major evaluation objectives, namely evaluating dynamic characteristics of a satellite structure and assessing its strength by loading vibrations equivalent to that at the launch.
On Oct. 2, the last vibration test was completed, then planned dynamic characteristics data was acquired and the strength of the satellite structure against a vibration load equivalent to that at the time of launch was verified.

The thermal vacuum test was held for the X-ray Astronomy Satellite “ASTRO-H” between June 24 and July 9 in a 13-meter chamber at the Tsukuba Space Center. The purposes of the thermal vacuum test are to verify the thermal model by exposing a satellite to the vacuum and thermal environment, and to confirm the function and performance of observation instruments in the on-orbit environment through an electric test.
All tested items were satisfactorily confirmed including the expected performance of the onboard instruments, verification of the command function to be used in orbit, and calibration data acquisition.

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 its preparations for launch are turning the final corner. We will work harder to overcome the many remaining hurdles including the functional test, thermal vacuum test, and vibration test.

The Soft Gamma-ray Detectors (SGD) to observe the soft gamma-ray region of 60 to 600 keV are under the thermal vacuum test in the 8-meter chamber at the Tsukuba Space Center to confirm their thermal design.
The sensor part of the SGD does not activate till the temperature hits a low temperature of minus 20 degrees (C). However, the SGDs will be installed outside of the satellite panel, thus their temperature will increase from radiation from the Sun and the Earth, thermal input from the satellite panel, and heat from a large amount of LSI (large-scale integrated circuits) and an amplifier if nothing is done. Therefore, the accumulating heat will be carried to the radiator through thermal transfer and a heat pipe to be released, and the SGD will be covered by the multi-layer insulation (MLI), which looks like a bunch of aluminum foils, to shut out heat input. The semiconductor sensor is also activated with high voltage of 200 to 1000 V, hence it should also be tested if it would discharge in vacuum.
Photo: The SGD-2 sits in the 8-meter chamber.

As manufacturing of two Hard X-ray Telescopes (HXTs) and two Soft X-ray Telescopes (SXTs) has been completed and their performance has been confirmed, they are going to be subject to the first integration test. During the test, the telescopes will be mounted on an optical board to make sure that there is no interference with other structures or the satellite bus as well as that no problems arise with operations for controlling the telescope position or angle and operation tools.
Photo: Satellite surrounded by a scaffold