Japan loses another H3 launcher, plus the satnav bird it carried

25 percent failure rate for JAXA's space truck, with the second stage again proving perilous

Japan’s Aerospace Exploration Agency (JAXA) has created a Special Task Force to investigate the failed launch of its H3 rocket on Monday.

The launch was the eighth for the H3, a medium-lift rocket that JAXA developed to replace the H-IIA launcher, which flew fifty times between 2001 and 2025 with just one mission failure.

The H3 can launch under its own power, or with assistance from two or four solid-fuel boosters. That versatility means it is suited to many missions.

The first H3 flight took place in March 2023 and failed when the rocket did not receive the command to ignite its second stage. The rocket therefore slowed and JAXA destroyed the vehicle.

The next six H3 missions all succeeded, but according to JAXA, during Monday’s launch “the second stage engine’s second ignition failed to start normally and shut down prematurely.”

The H3 now has a 25 percent failure rate, a problem for Japan and the world.

The rocket’s failure is bad news for Japan because the country’s space program is ambitious and strategic. Monday’s mission carried a single satellite named QZS-5, which was to form part of Japan’s seven-satellite navigation constellation and reduce its reliance on similar services controlled by other countries.

Japan is also a contributor to the Artemis program, the US-led effort to establish a human presence on the Moon. One part of that plan called for JAXA to use the H3 to launch a water-spotting satellite called LUPEX in 2027.

JAXA partnered with India’s Space Research Organization to work on LUPEX.

Speaking of ISRO, it’s counting down to Christmas Eve launch of its LVM3 rocket.

The payload on this mission is AST SpaceMobile’s BlueBird Block-2 satellite, a craft that will provide cellular broadband services accessible with everyday smartphones.

The mission is the sixth for the LVM3. ®