Japan's space program seeks reboot with Wednesday launch

Second test flight for failed H3 booster after a run of bad luck

Japan will on Wednesday try to reboot its space program with a second test flight for its H3 booster.

The H3 has been a decade in the making and can launch under its own power, or with the assistance of two or four external boosters. The craft's payload capabilities don't vastly exceed the workhorse H-IIA that Japan has successfully launched almost 50 times, but it is cheaper to operate. Japan's space exploration agency (JAXA) hopes the H3 will therefore allow it to launch more of its own payloads and win business. The launcher will also help JAXA's contributions to the International Space Station.

Sadly, March 2023's debut H3 launch did not go well. At the time, JAXA thought the command to ignite its second stage was not received. After observing telemetry suggesting the rocket had worryingly slowed its ascent, JAXA sent an instruction to self-destruct. That message was received and executed, sending the H3 and the land observation satellite it carried to their doom.

A subsequent investigation found the ignition command was probably received, but a minor short circuit in equipment used to ignite the second stage was the reason for the failure. The investigation found that short could be avoided with extra insulation and closer inspection of the rocket during assembly.

That work has presumably been undertaken – and checked many times over – ahead of Wednesday's second test.

This time around the H3 will carry three payloads.

One is romantically named the "Vehicle Evaluation Payload-4" and weighs about as much as the kind of payloads future H3 launches are hoped to hoist. It includes acoustic and temperature sensors, plus accelerometers, to help JAXA understand the launcher's performance.

An Earth imaging satellite named CE-SAT-1E and built by Canon is also aboard, along with an Earth observation CubeSat called TIRSAT.

Success for the H3 is devoutly to be wished, as JAXA has had a rotten run of luck recently. Its moon lander landed upside down and a recent launch of the Epsilon light lifter also failed.

India's space agency, ISRO, is also in action this week with a planned Saturday launch for the INSAT-3DS meteorological satellite atop a Geosynchronous Satellite Launch Vehicle. ®

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