Japan launches military communications satellite on 4th flight of H3 rocket

Japan's new H3 rocket flew for the fourth time ever on Monday morning (Nov. 4).

A Japanese H3 rocket launches the Kirameki 3 military communications satellite from Tanegashima Space Center on Nov. 4, 2024. (Image credit: JAXA)

The two-stage H3 is Japan's new workhorse medium-lift rocket, the successor to the H-2A, which is about to retire after more than two decades of service. The H-2A has just one mission left, and it's expected to lift off before the end of the year.

The H3, which was developed by JAXA and Mitsubishi Heavy Industries, debuted in March 2023, about three years later than originally planned.

That first launch failed, resulting in the loss of the payload — the Advanced Land Observing Satellite-3 (ALOS-3, also known as DAICHI-3).

a yellow and white rocket climbs into a blue sky. — Japan's H3 rocket carries the ALOS-4 Earth-observation satellite into the sky on June 30, 2024. (Image credit: JAXA)

— Japan's new H3 rocket reaches orbit for 1st time (video)

— The history of rockets

The rocket's next two flights were successful, however. This past February, the H3 carried a 5,900-pound (2,600 kilograms) mass simulator to orbit and also successfully deployed two small Earth-observation satellites.

Then, on June 30, the rocket delivered the ALOS-4, or DAICHI-4, Earth-observation satellite to low Earth orbit as planned.

Monday morning's launch targeted a more distant destination — geostationary orbit, which lies 22,236 miles (35,786 kilometers) above Earth. At this altitude, satellites complete one orbit in exactly one Earth day, meaning that satellites in geo "hover" over the same patch of the planet continuously.

According to NextSpaceflight.com, Kirameki 3 will be operated by DSN Corporation and "will be used for military communications by the Japanese military." The satellite will communicate in the X band, part of the microwave region of the electromagnetic spectrum.

Michael Wall is a Senior Space Writer with Space.com and joined the team in 2010. He primarily covers exoplanets, spaceflight and military space, but has been known to dabble in the space art beat. His book about the search for alien life, "Out There," was published on Nov. 13, 2018. Before becoming a science writer, Michael worked as a herpetologist and wildlife biologist. He has a Ph.D. in evolutionary biology from the University of Sydney, Australia, a bachelor's degree from the University of Arizona, and a graduate certificate in science writing from the University of California, Santa Cruz. To find out what his latest project is, you can follow Michael on Twitter.