JAXA Successfully Reaches Orbit on Second H3 Launch

Japan’s H3 rocket successfully reached orbit on its second attempt, 11 months after it failed during its debut flight. The launch took place at the Tanegashima Space Center and sent a mass simulator and two small satellites to a Sun-synchronous orbit. The H3 rocket was developed by the Japan Aerospace Exploration Agency (JAXA) and Mitsubishi Heavy Industries as a successor to the previous-generation H-IIA and H-IIB vehicles. This launch marked a significant milestone for the H3 rocket and its potential to carry out future operational missions.

The H3 rocket made its first flight on March 7, 2023, with the Advanced Land Observing Satellite 3 (ALOS-3) on board. While the mission proceeded nominally through the first stage, the rocket’s second stage failed to ignite, leading to the destruction of the vehicle. An investigation identified three possible causes of the failure, focusing on an abnormal power reading detected at the moment the second stage ignition command was sent. Changes were implemented to prevent these failure modes from occurring in future missions.

The second launch, designated Test Flight 2 (TF2), aimed to demonstrate that the issues from the maiden flight had been resolved. The primary payload for TF2 was the Vehicle Evaluation Payload 4 (VEP-4), which mimicked the presence of a spacecraft aboard the rocket without risking the loss of another large satellite in case of mission failure. TF2 followed a similar launch profile to TF1, and VEP-4 was built with the same mass as ALOS-3 to provide confidence in the rocket’s performance.

TF2 also carried two secondary payloads: CE-SAT-1E and TIRSAT. These smaller satellites took advantage of excess payload capacity to reach orbit. CE-SAT-1E, developed by Canon Electronics, is part of a series of lightweight imaging satellites that incorporate Canon’s commercial cameras. TIRSAT, a CubeSat, was designed for on-orbit validation of the Uncooled Small Infrared Sensor, which has potential applications in industrial monitoring and disaster management.

The H3 rocket is a two-stage vehicle powered by cryogenic liquid hydrogen and liquid oxygen propellants. It can fly in different configurations, varying the number of first-stage engines, solid rocket boosters, and payload fairing length. The TF2 mission used the H3-22S configuration with two first-stage engines and two solid rocket boosters. Changes were made to the second-stage engine igniter and propulsion system controllers based on the findings from TF1’s failure.

The launch took place at Launch Pad 2 (LP2) of the Yoshinobu Launch Complex, which was initially built as a backup pad for H-IIA launches but has since been used by the H-IIB and H3 rockets. The TF2 rocket experienced successful ignition and liftoff, with various stages separating as planned. The second stage ignited after staging and successfully injected H3 into low-Earth orbit. The payloads were deployed at different intervals during the mission.

After completing nearly a full orbit, the second stage performed a deorbit burn to ensure the safe reentry of the payload. The separation mechanism securing VEP-4 to the second stage was also tested to prevent it from becoming space debris. This successful test flight will pave the way for future operational missions of the H3 rocket, including deployments of resource-monitoring satellites, military communications satellites, and missions to the Moon and Mars.

Overall, the second launch of Japan’s H3 rocket demonstrated improvements made based on previous failures and showcased its potential for future space missions. With several more missions planned in the upcoming year, the H3 rocket is set to play an important role in Japan’s space program and international space exploration efforts.

[Lead image: H3 rollout ahead of the VEP 4 mission. Credit: MHI]