Japanese satellite and the sixth in a series of X-ray space telescopes developed by JAXA’s Institute of Space and Astronautical Science. Formerly ASTRO-H, Hitomi was launched on 17 February 2016 and placed into Earth orbit on an HII-A rocket fired from the Yoshinobu Launch Complex at Japan’s Tanegashima Space Center. Within a month of being launched, however, the craft vanished after ground crews lost contact with it, and it was feared to have broken apart. Before disappearing, the satellite sent back data on a galaxy cluster that revealed a surprisingly calm gas cloud within.