An international team observed the hot gas in the Perseus cluster with the Soft X-ray Spectrometer (SXS) on board the X-ray Astronomy Satellite ASTRO-H ("Hitomi") during its initial operation phase, which started one week after liftoff. The total integration time was 230,000 s.
The energy resolution of the SXS data was high, equaling the best resolution estimated during ground testing. The observation data demonstrated the good in-orbit performance of the SXS and its ability to measure the velocity of hot gas with at least 20 times better resolution than previous instruments.
This observation resulted in the first determination of the velocity of hot gas in the center of a galaxy cluster.
At the center of the Perseus cluster, a gigantic black hole emits powerful jets that collide with the surrounding hot gas and push it outward. For this reason, large turbulent flows of the hot gas were expected. However, the SXS observation revealed that the chaotic motion was small and the hot gas was calm, despite the violent conditions.
These results are presented in a paper published on July 7, 2016, in the journal Nature.

JAXA confirmed the completion of a sequence of important operations of the X-ray Astronomy Satellite “Hitomi” (ASTRO-H), including turning the cooling system on, test operation of the Soft X-ray Spectrometer (SXS), and extending the Extensible Optical Bench (EOB). With this confirmation, the critical operation phase of Hitomi was completed.
The Hitomi will take about one and half months to verify the function of its onboard equipment and instruments in space, then we will conduct calibration observations for another one and half months.

H-IIA F30 with the "ASTRO-H" onboard launched at 5:45 p.m. on Feb 17, 2016 (JST) from the Tanegashima Space Center. The rocket flew smoothly, and, at about 14 minutes after liftoff, "ASTRO-H" was separated from the H-IIA F30.
ASTRO-H is the eye to study the hot and energetic universe. Therefore we name ASTRO-H, "Hitomi". The word "Hitomi".generally means "eye", and specifically the pupil, or entrance window of the eye – the aperture!

The launch of the The X-ray Astronomy Satellite "ASTRO-H" by the H-IIA Launch Vehicle No. 30 was rescheduled at 5:45 p.m. on Feb 17 (Wed. Japan Standard Time, JST) after carefully studying the weather conditions.

The live launch report will begin at 5:25 p.m. on Feb 17(Wed. ,JST). The report will be broadcast through the Internet.
Please send your support messages for the mission!

H-IIA Launch Vehicle No.30 with the X-ray Astronomy Satellite "ASTRO-H" onboard, which was originally scheduled for February 12 (Fri.), 2016 (Japan Standard Time), has been rescheduled because bad weather is expected. The new launch day will be announced as soon as it is determined. Your warm support messages are welcomed at the support site.

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