Black Hole Explorer Mission Development in Japan
Abstract
The Black Hole Explorer (BHEX) is a next-generation space very-long-baseline interferometry (VLBI) mission concept that will extend existing ground-based millimeter/submillimeter VLBI arrays to space. The Japanese astronomical community has contributed to BHEX mission development through the BHEX Japan Consortium, established in 2023. This paper provides a high-level summary of progress in Japan since 2024, including the establishment of the Black Hole Explorer Working Group (BHEX WG) at the Institute of Space and Astronautical Science (ISAS), JAXA, to conduct the Japanese side of the Pre-Phase~A mission studies. We outline recent advances in key instrument technologies, including concept design studies of a 4.5\,K closed-cycle mechanical cryocooler and prototype development of an ultra-wideband 300\,GHz Superconductor--Insulator--Superconductor (SIS) mixer for BHEX. We also describe ongoing upgrades to Japan's ground infrastructure to support 86\,GHz observations with VERA and simultaneous 86+230\,GHz observations with the Nobeyama 45\,m Telescope.
Cite
@article{arxiv.2608.00890,
title = {Black Hole Explorer Mission Development in Japan},
author = {Kazunori Akiyama and Mareki Honma and Akihiro Doi and Shoko Koyama and Kotaro Niinuma and Kazuhiro Hada and Yuto Akiyama and Rebecca Baturin and Peter Galison and Paul Grimes and Yoshiaki Hagiwara and Takayuki J. Hayashi and Aya E. Higuchi and Janice Houston and Michael D. Johnson and Tomohisa Kawashima and Daniel P. Marrone and Yosuke Murayama and Ken Ohsuga and Hannah Rana and Hidetoshi Sano and Edward Tong and Yuh Tsunetoe and Yoshinori Uzawa},
journal= {arXiv preprint arXiv:2608.00890},
year = {2026}
}
Comments
Submitted to SPIE Conference Series, 13 pages (main text: 7 pages), 2 figures, SPIE Astronomical Telescopes + Instrumentation 2026