Japan Scores Success On Second H3 Launch

Japan Scores Success On Second H3 Launch

The Japan Aerospace Exploration Agency and Mitsubishi Heavy Industries succeeded in launching the new H3 rocket today almost a year after the first attempt failed. H3 will replace Japan’s existing H-IIA, providing more lift capability at lower cost.

Liftoff at 7:22:55 pm Eastern Standard Time tonight (9:22:55 am February 17 in Japan) from Tanegashima went as planned.

Japan’s H3 rocket on the launch pad awaiting launch, February 16, 2024 EST. Screengrab.


Today’s success comes just over 11 months after the first launch failed on March 6, 2023 EST.

The H3 program began in 2014 and the first launch was supposed to take place in 2020, but Mitsubishi Heavy Industries experienced challenges developing the LE-9 main engine — an expander bleed cycle engine — for the first stage.  That stage worked perfectly last March, but the second stage, an existing design, failed when a short circuit prevented the engines from receiving the ignition signal.

The failure destroyed a very important earth observing satellite, ALOS-3 or Daichi-3. This time they only put a mass simulator, Vehicle Evaluation Payload 4, onboard plus two cubesats, CE-SAT-1E and TIRSAT.

H3 is 63 meters (207 feet) tall with a diameter of 5.2 meters (17 feet). Several configurations are available that can place as much as 4,000 kilograms (8,800 pounds) into sun-synchronous orbit or 7,900 kg (17,400 lbs) into geosynchronous transfer orbit. Japan expects the H3 to be more competitive on the world market and can send payloads as far as the Moon. JAXA is one of the international partners building the Gateway space station with NASA that will support lunar landing missions for the Artemis program. JAXA anticipates using the H3 for logistical support.

H3 rocket variants. Credit: JAXA

JAXA already is a long-standing partner in the International Space Station program — Satoshi Furukawa is aboard right now — and the H3 will be used to resume Japanese cargo flights to ISS. Japan’s HTV is the largest of the cargo vehicles that resupply ISS. The last of the original series was launched in May 2020. The new version, HTV-X, requires the H3 rocket.

This article has been updated.

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