spacetoday.net: Upper stage malfunction dooms H3 launch of navigation satellite

Posted: Sun, Dec 28, 2025, 9:43 AM ET (1443 GMT)
An H3 launch of a Japanese navigation satellite failed Dec. 21 when the rocket’s upper stage malfunctioned. The H3 lifted off from the Tanegashima Space Center at 8:51 ppm EST (0151 GMT Dec. 22). The rocket’s first stage performed normally, but the first burn of the second stage lasted nearly 30 seconds longer than planned. The upper stage engine shut down almost immediately after startup for a second burn, stranding the stage and its payload, the Michibiki 5 navigation satellite, in a very low orbit that will cause them to soon reenter. The investigation is focusing on the rocket’s payload fairing, with JAXA stating there was a larger impact than usual on the rocket when its payload fairing separated. That coincided with a drop in pressure in the liquid hydrogen tank in the rocket’s upper stage, which caused lower thrust from the upper stage’s engine.