X-Ray Imaging and Spectroscopy Mission

With the retirement of Suzaku in September 2015, and the detectors onboard Chandra X-ray Observatory and XMM-Newton operating for more than 15 years and gradually aging, the failure of Hitomi meant that X-ray astronomers would have a 13-year blank period in soft X-ray observation, until the launch of ATHENA in 2035. This would result in a major setback for the international community, as studies performed by large scale observatories in other wavelengths, such as the James Webb Space Telescope and the Thirty Meter Telescope were planned to commence in the early 2020s, while there would be no telescope to cover the most important part of X-ray astronomy. With its successful launch in September 2023, XRISM is expected to cover the science that was lost with Hitomi, such as the structure formation of the universe, feedback from galaxies/active galaxy nuclei, and the history of material circulation from stars to galaxy clusters. The space telescope will also take over Hitomi role as a technology demonstrator for the European Advanced Telescope for High Energy Astrophysics (ATHENA) telescope. In Japan, the project is led by JAXA's Institute of Space and Astronautical Science (ISAS) division, and U.S. participation is led by NASA's Goddard Space Flight Center (GSFC). The U.S. contribution is expected to cost around US$80 million, which is about the same amount as the contribution to Hitomi. Changes from Hitomi Assembly XMA The X-ray Imaging and Spectroscopy Mission is one of the first projects for ISAS to have a separate project manager (PM) and primary investigator (PI). This is part of ISAS's reform in project management to prevent the recurrence of the Hitomi accident. The elimination of a hard X-ray telescope was justified by the 2012 launch of NASA's NuSTAR satellite, which did not exist when Hitomi (then known as the New X-Ray Telescope, NeXT) was initially formulated. NuSTAR's spatial and energy resolution is analogous to Hitomi hard X-ray instruments. Once XRISM operation starts, collaborative observations with NuSTAR will likely be essential. Meanwhile, the scientific value of the soft and hard X-ray band width boundary has been noted; therefore the option of upgrading XRISM instruments to be partially capable of hard X-ray observation is under consideration. A hard X-ray telescope with abilities surpassing Hitomi was proposed in 2017. The FORCE (Focusing On Relativistic universe and Cosmic Evolution) space telescope is a candidate for the next ISAS competitive medium class mission. If selected, FORCE would be launched after the mid-2020s, with an eye towards conducting simultaneous observations with ATHENA. == History ==

Following the premature termination of the Hitomi mission, on 14 June 2016 JAXA announced their proposal to rebuild the satellite. The XARM pre-project preparation team was formed in October 2016. In the U.S. side, formulation began in the summer of 2017. In June 2017, ESA announced that they would participate in XARM as a mission of opportunity. == Instruments ==

|thumb|An illustration of the range of cosmic temperatures including the temperature at which XRISM will work to ensure the optimal functioning of its instruments XRISM carries two instruments for studying the soft X-ray energy range, Resolve and Xtend. The satellite has separate telescopes for each of the instruments, SXT-I (Soft X-ray Telescope for Imager) and SXT-S (Soft X-ray Telescope for Spectrometer). == Launch ==

JAXA launched XRISM on 6 September 2023 at 23:42 UTC (7 September 08:42 Japan Standard Time) using an H-IIA rocket from Tanegashima Space Center. XRISM was successfully inserted into orbit on the same day, and the accompanying launch payload, SLIM, began its multi-month journey to the Moon. A protective shutter over the Resolve instrument's detector has failed to open. This does not prevent the instrument from operating, but limits it to observing X-rays of energy and above, as opposed to the planned . A similar shutter over Xtend has opened normally. == See also ==