The Hitomi (ASTRO-H) mission is the sixth Japanese x-ray astronomy satellite developed by a large international collaboration, including Japan, USA, Canada, and Europe. The mission aimed to provide the highest energy resolution ever achieved at E > 2 keV, using a microcalorimeter instrument, and to cover a wide energy range spanning four decades in energy from soft x-rays to gamma rays. After a successful launch on February 17, 2016, the spacecraft lost its function on March 26, 2016, but the commissioning phase for about a month provided valuable information on the onboard instruments and the spacecraft system, including astrophysical results obtained from first light observations. The paper describes the Hitomi (ASTRO-H) mission, its capabilities, the initial operation, and the instruments/spacecraft performances confirmed during the commissioning operations for about a month.
The Hitomi (ASTRO-H) mission is the sixth Japanese X-ray astronomy satellite developed by a large international collaboration, including Japan, USA, Canada, and Europe. The mission aimed to provide the highest energy resolution ever achieved at E > 2 keV, using a microcalorimeter instrument, and to cover a wide energy range spanning four decades in energy from soft X-rays to gamma-rays. After a successful launch on 2016 February 17, the spacecraft lost its function on 2016 March 26, but the commissioning phase for about a month provided valuable information on the on-board instruments and the spacecraft system, including astrophysical results obtained from first light observations. The paper describes the Hitomi (ASTRO-H) mission, its capabilities, the initial operation, and the instruments/spacecraft performances confirmed during the commissioning operations for about a month.
XEUS is the potential successor to ESA's XMM-Newton X-ray observatory. Novel light-weight optics with an effective area of 10 m<sup>2</sup> at 1 keV and 2-5" HEW spatial resolution together with advanced imaging detectors will provide a sensitivity around 200 times better than XMM-Newton as well as much improved high-energy coverage, and spectroscopic performance. This enormous improvement in scientific capability will open up new vistas in X-ray astronomy. It will allow the detection of massive black holes in the earliest AGN and estimates of their mass, spin and red-shift through their Fe-K line properties. XEUS will study the first gravitationally bound, Dark Matter dominated, systems small groups of galaxies and trace their evolution into today's massive clusters. High-resolution spectroscopy of the hot intra-cluster gas will be used to investigate the evolution of metal synthesis to the present epoch. The hot filamentary structure will be studied using absorption line spectroscopy allowing the mass, temperature and density of the intergalactic medium to be characterized. As well as these studies of the deep universe, the enormous low-energy collecting area will provide a unique capability to investigate bright nearby objects with dedicated high-throughput, polarimetric and time resolution detectors.
In various objects, it has been evident that non-thermal processes are
playing important roles in high energy objects. They become
outstanding above 10 keV and its total energy could be comparable to
that of thermal components. In order to examine such non-thermal
processes, we propose a hard X-ray imaging mission NeXT (New X-ray
Telescope mission) together with the soft gamma ray detector and the
high resolution spectrometer. Hard X-ray telescopes consist of
multilayer coated high through put mirrors. The focal plane detectors
are hybrid type imaging detectors to cover both soft and hard
X-rays. Total performance in sensitivity for a point source reaches
100 times better than any currently scheduled missions in 10 - 60(80)
keV range and 10 times better in soft gamma rays. It is planned to
launch it in the time frame of 2011.
Astro-E2 will be the fifth in a series of X-ray observatory of Institute of Space and Astronautical Science (ISAS) of Japan Aerospace Exploration Agency (JAXA) and is being developed by international collaboration lead by ISAS/JAXA and NASA. The main features of the mission are high-sensitivity broadband and high-resolution X-ray spectroscopy. The spacecraft, the scientific payloads, and expected in-orbit performance and science output are described with emphasis on the high resolution X-ray spectrometer, XRS.
Next Japanese X-ray mission after AstroE2 will be dedicated to the exploration of non-thermal phenomena in the Universe by the hard X-ray imaging, high resolution spectroscopy and broad band coverage. The objectives are the non-thermal X-ray components in cluster of galaxies and SNR, hidden AGN and their contribution to the cosmic X-ray background. Such non-thermal energy is considerable amount of the total energy in the Universe. Multilayer supermirror hard X-ray telescopes (50 cm diameter and 12 m focal length) will focus hard X-rays up to 60 keV or higher. Hybrid X-ray imaging system consisted of CCD cameras for soft X-ray imaging and a hard X-ray imaging detector will be placed at the focal points of four multilayer telescopes. A micro-calorimeter array detector is prepared for a soft X-ray telescope to perform imaging spectrometry (60 cm diameter and 8 m focal length). A soft gamma-ray detector will cover up to several hundred keV. It will provide extremely low background by imaging capability. This X-ray mission is now named "NeXT", which stands for "New X-ray Telescope mission" or "Non-thermal Energy eXpring Telescope mission." It will be launched in 2010 by an M-V rocket.
Astro-E2 will be the fifth in a series of Japanese X-ray astronomy satellites, following Hakucho, Tenma, Ginga and ASCA. This mission is a re-challenge of the Astro-E mission, which the Institute of Space and Astronautical Science (ISAS) failed to place on a stable orbit on February 10, 2000, and the Astro-E2 satellite will be basically identical to the Astro-E satellite. It will be an international X-ray astronomy observatory characterized by the superior energy resolution of the X-ray micro-calorimeter (XRS) placed at the focal plane of the X-ray telescope (XRT) and by the wide band spectroscopy with the CCD cameras (XIS) + XRTs system and the hard X-ray detector (HXD). It is now being developed in an extensive collaboration between scientists from Japan and the United States.
Strategy of formation flying for the X-ray Evolving Universe
Spectroscopy mission (XUES) is discussed, in which an X-ray telescope
of 10 m diameter and 50 m focal length will be constructed in orbit by
formation flying the X-ray mirror and the focal plane X-ray detectors
on two separate spacecrafts. We first studied the thrust force
required to keep the detector spacecraft (DSC) in the non-Keplerian
orbit. We find the direction of the thrust vector rotates twice per a
single spacecraft orbital evolution along a circle parallel to the
orbital plane. The absolute value of thrust needs to be varied by a
factor of two or less. The maximum thrust force required is 0.47 N
assuming a 600 km altitude and a 4000 kg DSC mass. The present
baseline design requires no moving mechanism, instead requires a large
amount of propellant because of relatively low thruster efficiency.
The spacecraft is estimated to weigh about 6000 kg. We studied an
alternative design in which the thruster efficiency is optimized and
showed that the spacecraft mass can be reduced to 4000 kg. This,
however, requires a rotation mechanism and additional constraints on
the spacecraft operation.
One of the major fields to be explored in the 21st century is the hard X-ray sky up to 50 keV or 100 keV. Above 10 keV, thermal components start to decay rapidly and then non-thermal power law continua become dominant. For example, some of SNR and Cluster of Galaxies exhibit substantial non-thermal components, which suggest high energy electrons. We would like to investigate acceleration mechanisms of such high energy particles by observing hard X-ray images and their spectra. In order to perform imaging observations in hard X-ray range up to 50 keV, supermirror hard X-ray telescopes are most promising. We have studied to put Pt/C supermirror on the mirror shells of a high throughput X-ray telescope. The first satellite mission proposed with the supermirror hard X-ray telescope is our New X-ray Telescope mission (NeXT) in Japan to be launched 2010. 6-7 supermirror telescopes will be installed at the top of an extensible optical bench. The hybrid X-ray imager will be placed on the focal plane to observe hard X-ray images up to 50 keV with CdTe pixel detector underneath a thin CCD for soft X-ray imaging. For high resolution spectroscopy, TES type calorimeters are considered without cryogen. Non-imaging hard X-ray and soft gamma ray detector is studied to achieve unprecedented sensitivity between 50 and 300 keV. NeXT will be a sort of pathfinder of hard X-ray astronomy not only technically but also scientifically.
XEUS: The X-ray Evolving Universe Spectroscopy mission represents a potential follow-on mission to the ESA XMM cornerstone currently nearing completion. XEUS represents the next logical step forward in x-ray astrophysics after the current set of mission have been launched and completed their operational lives. The development and ultimate success relies heavily on the capability of the International Space Station (ISS). In this paper we describe the key characteristics of the mission including the requirements placed specifically on the ISS and discuss the significant advances in high energy astrophysics expected from such an observatory.