Today marks exactly three years since XRISM was launched on September 7, 2023 (JST). We would like to express our sincere gratitude to everyone who has supported and contributed to the mission over the past three years. XRISM was originally planned as a three-year mission. However, following a scientific review by the ISAS Space Science Committee and other assessments, the project has been approved for extension through March 2030. As long as the instruments remain healthy and XRISM continues to deliver significant scientific results, we hope to continue scientific observations for as long as possible beyond that date.

Resolve, the primary instrument aboard XRISM, is currently operating with its gate valve still closed. Nevertheless, its spectral performance in the 6–9 keV energy band, where prominent iron emission and absorption lines are found, has significantly exceeded its original performance requirement, enabling XRISM to produce numerous groundbreaking scientific results. During the next three and a half years of extended mission period, we will pursue new approaches to scientific operations, including strategic large-scale observing programs (“Key Program”), while continuing to make every possible effort to open the Resolve gate valve.

With the start of the extended mission period, the XRISM project is also transitioning to a new leadership structure. Makoto Tashiro (Saitama University), who has served as Principal Investigator, will assume the role of Mission Scientist. Hiroya Yamaguchi (ISAS/JAXA), who has served as Deputy Project Scientist, will succeed him as Principal Investigator. We also welcome Hirofumi Noda (Tohoku University) as the new Deputy Project Scientist. As before, the scientific operations of the satellite will be carried out by a dedicated team of primarily young researchers (pictured). As XRISM enters this new stage, we sincerely appreciate your continued support for the mission.

Finally, during the nominal operations phase following launch, we received invaluable support from the companies listed below.

• SPACE ENGINEERING DEVELOPMENT Co., Ltd.
  • Spacecraft operations in nominal operation phase
• NEC Corporation
  • Spacecraft system contractor
  • Operation support in nominal operation phase
• Sumitomo Heavy Industries, Ltd.
  • Manufacturer of Resolve cooling system
  • Operation support in nominal operation phase
• Fujitsu Limited
  • Infrastructure maintenance of data transmission
  • System and spacecraft operation system
• Mitsubishi Heavy Industries, Ltd.
  • Manufacturer of Xtend system and Resolve PSP
  • Operation support in nominal operation phase