, also known as ASTRO-H and New X-ray Telescope (NeXT), was an
X-ray astronomy satellite commissioned by the Japan Aerospace Exploration Agency (
JAXA
The is the Japanese national air and space agency. Through the merger of three previously independent organizations, JAXA was formed on 1 October 2003. JAXA is responsible for research, technology development and launch of satellites into orb ...
) for studying extremely energetic processes in the
Universe
The universe is all of space and time and their contents, including planets, stars, galaxies, and all other forms of matter and energy. The Big Bang theory is the prevailing cosmological description of the development of the universe. Acc ...
. The space observatory was designed to extend the research conducted by the
Advanced Satellite for Cosmology and Astrophysics
The Advanced Satellite for Cosmology and Astrophysics (ASCA, formerly named ASTRO-D) was the fourth cosmic X-ray astronomy mission by JAXA, and the second for which the United States provided part of the scientific payload. The satellite was succ ...
(ASCA) by investigating the hard X-ray band above 10
keV Kev can refer to:
Given name
* Kev Adams, French comedian, actor, screenwriter and film producer born Kevin Smadja in 1991
* Kevin Kev Carmody (born 1946), Indigenous Australian singer-songwriter
* Kev Coghlan (born 1988), Scottish Grand Prix motor ...
. The satellite was originally called New X-ray Telescope;
at the time of launch it was called ASTRO-H.
After it was placed in orbit and its
solar panels
A solar cell panel, solar electric panel, photo-voltaic (PV) module, PV panel or solar panel is an assembly of photovoltaic solar cells mounted in a (usually rectangular) frame, and a neatly organised collection of PV panels is called a phot ...
deployed, it was renamed ''Hitomi''.
The spacecraft was launched on 17 February 2016 and contact was lost on 26 March 2016, due to multiple incidents with the
attitude control
Attitude control is the process of controlling the orientation of an aerospace vehicle with respect to an inertial frame of reference or another entity such as the celestial sphere, certain fields, and nearby objects, etc.
Controlling vehicle ...
system leading to an uncontrolled spin rate and breakup of structurally weak elements.
Name
The new name refers to the
pupil of an eye, and to a legend of a painting of four dragons.
The word Hitomi generally means "
eye
Eyes are organs of the visual system. They provide living organisms with vision, the ability to receive and process visual detail, as well as enabling several photo response functions that are independent of vision. Eyes detect light and conv ...
", and specifically the
pupil
The pupil is a black hole located in the center of the iris of the eye that allows light to strike the retina.Cassin, B. and Solomon, S. (1990) ''Dictionary of Eye Terminology''. Gainesville, Florida: Triad Publishing Company. It appears black ...
, or entrance window of the eye - the aperture. There is also an ancient legend that inspires the name Hitomi. "One day, many years ago, a painter was drawing four white dragons on a street. He finished drawing the dragons, but without "Hitomi". People who looked at the painting said "why don't you paint Hitomi, it is not complete. The painter hesitated, but people pressured him. The painter then drew Hitomi on two of the four dragons. Immediately, these dragons came to life and flew up into the sky. The two dragons without Hitomi remained still". The inspiration of this story is that Hitomi is regarded as the "One last, but most important part", and so we wish ASTRO-H to be the essential mission to solve mysteries of the universe in X-rays. Hitomi refers to the aperture of the eye, the part where incoming light is absorbed. From this, Hitomi reminds us of a black hole. We will observe Hitomi in the Universe using the Hitomi satellite.
Objectives
''Hitomi'' objectives were to explore the large-scale structure and evolution of the universe, as well as the distribution of dark matter within galaxy clusters
and how the galaxy clusters evolve over time;
how matter behaves in strong gravitational fields
(such as matter inspiraling into black holes),
to explore the physical conditions in regions where cosmic rays are accelerated,
as well as observing supernovae.
In order to achieve this, it was designed to be capable of:
* Imaging and
spectroscopic
Spectroscopy is the field of study that measures and interprets the electromagnetic spectra that result from the interaction between electromagnetic radiation and matter as a function of the wavelength or frequency of the radiation. Matter wav ...
measurements with a hard
X-ray telescope
An X-ray telescope (XRT) is a telescope that is designed to observe remote objects in the X-ray spectrum. In order to get above the Earth's atmosphere, which is opaque to X-rays, X-ray telescopes must be mounted on high altitude rockets, balloon ...
;
* Spectroscopic observations with an extremely high energy resolution using the micro-calorimeter;
* Sensitive wideband observations over the energy range 0.3-600 keV.
It was the sixth of a series of JAXA X-ray satellites,
which started in 1979,
and it was designed to observe sources that are an order of magnitude fainter than its predecessor,
Suzaku.
Its planned mission length was three years.
At the time of launch, two other large X-ray satellites were carrying out observations in orbit: the
Chandra X-ray Observatory
The Chandra X-ray Observatory (CXO), previously known as the Advanced X-ray Astrophysics Facility (AXAF), is a Flagship-class space telescope launched aboard the during STS-93 by NASA on July 23, 1999. Chandra is sensitive to X-ray sources 1 ...
and
XMM-Newton
''XMM-Newton'', also known as the High Throughput X-ray Spectroscopy Mission and the X-ray Multi-Mirror Mission, is an X-ray space observatory launched by the European Space Agency in December 1999 on an Ariane 5 rocket. It is the second cornerst ...
, both of which were launched in 1999.
Instruments
![xray_telescope_lens](https://upload.wikimedia.org/wikipedia/commons/5/59/Xray_telescope_lens.svg)
The probe carried four instruments and six detectors to observe photons with energies ranging from soft
X-ray
An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...
s to
gamma ray
A gamma ray, also known as gamma radiation (symbol γ or \gamma), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves, typically ...
s, with a high energy resolution.
''Hitomi'' was built by an international collaboration led by JAXA with over 70 contributing institutions in Japan, the United States, Canada, and Europe,
and over 160 scientists.
With a mass of ,
At launch, ''Hitomi'' was the heaviest Japanese X-ray mission.
The satellite is about in length.
Two soft X-ray telescopes (SXT-S, SXT-I), with focal lengths of , focus light onto a soft X-ray Spectrometer (SXS), provided by
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research.
NASA was established in 1958, succeeding t ...
, with an energy range of 0.4-12 keV for high-resolution
X-ray spectroscopy
X-ray spectroscopy is a general term for several spectroscopic techniques for characterization of materials by using x-ray radiation.
Characteristic X-ray spectroscopy
When an electron from the inner shell of an atom is excited by the energy o ...
,
and a soft X-ray imager (SXI), with an energy range of 0.3-12 keV.
Two hard X-ray telescopes (HXT), with a focus length of ,
focus light onto two hard X-ray imagers (HXI),
with energy range 5-80 keV,
which are mounted on a plate placed at the end of the extendable optical bench (EOB) that is deployed once the satellite is in orbit.
The
Canadian Space Agency
The Canadian Space Agency (CSA; french: Agence spatiale canadienne, ASC) is the national space agency of Canada, established in 1990 by the ''Canadian Space Agency Act''.
The president is Lisa Campbell, who took the position on September 3, 2020 ...
(CSA) provided the Canadian ASTRO-H Metrology System (CAMS),
which is a laser alignment system that will be used to measure the distortions in the extendible optical bench.
Two soft Gamma-ray detectors (SGD), each containing three units, were mounted on two sides of the satellite, using non-focusing detectors to observe soft gamma-ray emission with energies from 60 to 600 KeV.
The
Netherlands Institute for Space Research
SRON Netherlands Institute for Space Research is the Dutch expertise institute for space research. The Institute develops and uses innovative technology for research in space, focusing on astrophysical research, Earth science and planetary resea ...
(SRON) in collaboration with the
University of Geneva
The University of Geneva (French: ''Université de Genève'') is a public research university located in Geneva, Switzerland. It was founded in 1559 by John Calvin as a theological seminary. It remained focused on theology until the 17th centu ...
provided the filter-wheel and calibration source for the
spectrometer
A spectrometer () is a scientific instrument used to separate and measure spectral components of a physical phenomenon. Spectrometer is a broad term often used to describe instruments that measure a continuous variable of a phenomenon where the ...
.
Launch
The launch of the satellite was planned for 2013 as of 2008,
later revised to 2015 as of 2013.
As of early February 2016, it was planned for 12 February, but was delayed due to poor weather forecasts.
''Hitomi'' launched on 17 February 2016 at 08:45
UTC into a
low Earth orbit
A low Earth orbit (LEO) is an orbit around Earth with a period of 128 minutes or less (making at least 11.25 orbits per day) and an eccentricity less than 0.25. Most of the artificial objects in outer space are in LEO, with an altitude never mor ...
of approximately .
The circular orbit had an
orbital period
The orbital period (also revolution period) is the amount of time a given astronomical object takes to complete one orbit around another object. In astronomy, it usually applies to planets or asteroids orbiting the Sun, moons orbiting planets ...
of around 96 minutes, and an
orbital inclination
Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a reference plane and the orbital plane or axis of direction of the orbiting object.
For a satellite orbiting the Earth ...
of 31.01°.
It was launched from the
Tanegashima Space Center
The (TNSC) is the largest rocket-launch complex in Japan with a total area of about 9.7 square kilometers. It is located on the southeast coast of Tanegashima, an island approximately south of Kyushu. It was established in 1969 when the ...
on board an
H-IIA
H-IIA (H-2A) is an active expendable launch system operated by Mitsubishi Heavy Industries (MHI) for the Japan Aerospace Exploration Agency. These liquid fuel rockets have been used to launch satellites into geostationary orbit; lunar or ...
launch vehicle.
14 minutes after launch, the satellite separated from the launch vehicle. The solar arrays later deployed according to plan, and it began its on-orbit checkout.
Loss of spacecraft
On 27 March 2016,
JAXA
The is the Japanese national air and space agency. Through the merger of three previously independent organizations, JAXA was formed on 1 October 2003. JAXA is responsible for research, technology development and launch of satellites into orb ...
reported that communication with ''Hitomi'' had "failed from the start of its operation" on 26 March 2016 at 07:40 UTC.
On the same day, the U.S.
Joint Space Operations Center
The Combined Space Operations Center (CSpOC) is a U.S.–led multinational space operations center that provides command and control of space forces for United States Space Command's Combined Force Space Component Command. The CSpOC is located at ...
(JSpOC) announced on
Twitter
Twitter is an online social media and social networking service owned and operated by American company Twitter, Inc., on which users post and interact with 280-character-long messages known as "tweets". Registered users can post, like, and ...
that it had observed a breakup of the satellite into 5 pieces at 08:20 UTC on 26 March 2016,
and its orbit also suddenly changed on the same day.
Later analysis by the JSpOC found that the fragmentation likely took place around 01:42 UTC, but that there was no evidence the spacecraft had been struck by debris.
Between 26 and 28 March 2016, JAXA reported receiving three brief signals from ''Hitomi''; while the signals were offset by 200 kHz from what was expected from ''Hitomi'', their direction of origin and time of reception suggested they were legitimate.
Later analysis, however, determined that the signals were not from ''Hitomi'' but from an unknown radio source not registered with the
International Telecommunication Union
The International Telecommunication Union is a specialized agency of the United Nations responsible for many matters related to information and communication technologies. It was established on 17 May 1865 as the International Telegraph Unio ...
.
JAXA stated they were working to recover communication and control over the spacecraft,
but that "the recovery will require months, not days".
Initially suggested possibilities for the communication loss is that a helium gas leak, battery explosion, or stuck-open thruster caused the satellite to start rotating, rather than a catastrophic failure.
JAXA announced on 1 April 2016 that ''Hitomi'' had lost attitude control at around 19:10 UTC on 25 March 2016. After analysing engineering data from just before the communication loss, however, no problems were noted with either the helium tank or batteries.
The same day, JSpOC released orbital data for ten detected pieces of debris, five more than originally reported, including one piece that was large enough to initially be confused with the main body of the spacecraft.
Amateur trackers observed what was believed to be ''Hitomi'' tumbling in orbit, with reports of the main spacecraft body (Object A) rotating once every 1.3 or 2.6 seconds, and the next largest piece (Object L) rotating every 10 seconds.
JAXA ceased efforts to recover the satellite on 28 April 2016, switching focus to anomaly investigation.
It was determined that the chain of events that led to the spacecraft's loss began with its
inertial reference unit
An inertial reference unit (IRU) is a type of inertial sensor which uses gyroscopes (electromechanical, ring laser gyro or MEMS) and accelerometers (electromechanical or MEMS) to determine a moving aircraft’s or spacecraft’s change in rotatio ...
(IRU) reporting a rotation of 21.7° per hour at 19:10 UTC on 25 March 2016, though the vehicle was actually stable. The
attitude control
Attitude control is the process of controlling the orientation of an aerospace vehicle with respect to an inertial frame of reference or another entity such as the celestial sphere, certain fields, and nearby objects, etc.
Controlling vehicle ...
system attempted to use ''Hitomi''
reaction wheel
A reaction wheel (RW) is used primarily by spacecraft for three-axis attitude control, and does not require rockets or external applicators of torque. They provide a high pointing accuracy, and are particularly useful when the spacecraft must be ...
s to counteract the non-existent spin, which caused the spacecraft to rotate in the opposite direction. Because the IRU continued to report faulty data, the reaction wheels began to accumulate excessive momentum, tripping the spacecraft's computer into taking the vehicle into "safe hold" mode. Attitude control then tried to use its thrusters to stabilise the spacecraft; the
Sun sensor
A sun sensor is a navigational instrument used by spacecraft to detect the position of the sun. Sun sensors are used for attitude control, solar array pointing, gyro updating, and fail-safe recovery.
In addition to spacecraft, sun sensors find us ...
was unable to lock on to the Sun's position, and continued thruster firings caused ''Hitomi'' to rotate even faster due to an incorrect software setting. Because of this excessive rotation rate, early on 26 March 2016 several parts of the spacecraft broke away, likely including both solar arrays and the extended optical bench.
Replacement
Reports of a ''Hitomi'' replacement mission first surfaced on 21 June 2016.
According to an article from
Kyodo News
is a nonprofit cooperative news agency based in Minato, Tokyo. It was established in November 1945 and it distributes news to almost all newspapers, and radio and television networks in Japan. The newspapers using its news have about 50 millio ...
, JAXA was considering a launch of "Hitomi 2" in the early 2020s aboard Japan's new
H3 launch vehicle
The H3 Launch Vehicle is an expendable launch system in development in Japan. H3 launch vehicles are liquid-propellant rockets with strap-on solid rocket boosters and are planned to be launched from Tanegashima Space Center in Japan. Mitsubish ...
.
The spacecraft would be a near-copy of ''Hitomi''.
However, a 27 June 2016 article from ''
The Nikkei
''The Nikkei'', also known as , is the flagship publication of Nikkei, Inc. (based in Tokyo) and the world's largest financial newspaper, with a daily circulation exceeding 1.73 million copies. The Nikkei 225, a stock market index for the Tok ...
'' stated that some within the
Ministry of Education, Culture, Sports, Science and Technology
The , also known as MEXT or Monka-shō, is one of the eleven Ministries of Japan that composes part of the executive branch of the Government of Japan. Its goal is to improve the development of Japan in relation with the international community ...
believed it was too early to grant funding for a ''Hitomi'' replacement. The article also noted that
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research.
NASA was established in 1958, succeeding t ...
had expressed support for a replacement mission led by Japan.
On 14 July 2016, JAXA published a press release regarding the ongoing study of a successor.
According to the press release, the spacecraft would be a remanufacture but with countermeasures reflecting ''Hitomi'' loss, and would be launched in 2020 on a
H-IIA
H-IIA (H-2A) is an active expendable launch system operated by Mitsubishi Heavy Industries (MHI) for the Japan Aerospace Exploration Agency. These liquid fuel rockets have been used to launch satellites into geostationary orbit; lunar or ...
launch vehicle. The scientific mission of the "ASTRO-H Successor" would be based around the
SXS
SxS (S-by-S) is a flash memory standard compliant to the Sony and SanDisk-created ExpressCard standard. According to Sandisk and Sony, the cards have transfer rates of 800 Mbit/s and burst transfer rate of up to 2.5 Gbit/s over the ExpressCard's ...
instrument.
The Minister of Education, Culture, Sports, Science and Technology,
Hiroshi Hase
is a Japanese politician who is currently the governor of Ishikawa Prefecture. He served as the Minister of Education, Culture, Sports, Science and Technology under Prime Minister Shinzō Abe. Prior to his appointment in the Cabinet, he also se ...
, stated during a press conference on 15 July 2016 that funding for ''Hitomi'' successor will be allocated in the fiscal year 2017 budget request, and that he intends to accept the successor mission on the condition that the investigation of ''Hitomi'' destruction is completed and measures to prevent recurrence are done accordingly.
The
X-Ray Imaging and Spectroscopy Mission
The X-Ray Imaging and Spectroscopy Mission (XRISM, pronounced "crism"), formerly the X-ray Astronomy Recovery Mission (XARM), is an X-ray astronomy satellite of the Japan Aerospace Exploration Agency (JAXA) to provide breakthroughs in the stud ...
(XRISM) was approved by
JAXA
The is the Japanese national air and space agency. Through the merger of three previously independent organizations, JAXA was formed on 1 October 2003. JAXA is responsible for research, technology development and launch of satellites into orb ...
and
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research.
NASA was established in 1958, succeeding t ...
in April 2017, with launch planned in 2023.
See also
*
List of X-ray space telescopes
X-ray telescopes are designed to observe the x-ray region of the electromagnetic spectrum. X-rays from outer space cannot be observed from the ground due to absorption by the atmosphere, and so x-ray telescopes must be launched into orbit. Their m ...
*
X-ray astronomy
*
List of software bugs
Many software bugs are merely annoying or inconvenient but some can have extremely serious consequences – either financially or as a threat to human well-being. The following is a list of software bugs with significant consequences.
Space
* ...
References
External links
''Hitomi'' websiteby JAXA
''Hitomi'' websiteby JAXA's Institute of Space and Astronautical Science
''Hitomi'' websiteby NASA
{{Orbital launches in 2016
Space telescopes
Satellites of Japan
X-ray telescopes
Spacecraft launched in 2016
2016 in Japan
Spacecraft launched by H-II rockets
Derelict satellites orbiting Earth