KAGOSHIMA - Japan's H3 Rocket No. 6 lifted off from the Tanegashima Space Center in Kagoshima Prefecture at 9:53 a.m. on June 12, marking the first launch in about six months since the failure of H3 Rocket No. 8 and a critical step toward the full resumption of operational flights.
The rocket carried a payload verification package along with small secondary satellites and rose steadily toward space after its main engine ignited and lift-off was confirmed. As the vehicle climbed, the sound of the launch echoed across the area while the rocket gradually disappeared into cloud cover.
Mission controllers reported that the rocket continued flying normally as it headed out over the Pacific Ocean. Unlike previous H3 launches, the mission was conducted without the use of side-mounted solid rocket boosters, making it the first launch of its kind for the H3 program.
Attention focused on the fairing separation sequence shortly after the three-minute mark. Investigators believe damage caused by the shock of fairing separation was a key factor in the failure of H3 Rocket No. 8. At approximately 3 minutes and 48 seconds after launch, officials announced that the fairing protecting the payload had separated as planned.
The successful fairing separation cleared the first major milestone in the mission and indicated that the modifications introduced following the previous failure were functioning as intended.
At the time of the announcement, the rocket had reached an altitude of about 90 kilometers and was traveling at roughly 2.6 kilometers per second while continuing along its planned trajectory.
The mission was scheduled to proceed with first-stage separation and ignition of the second-stage engine in space. A successful insertion into the planned orbit would officially qualify the launch as a success, after which the onboard small satellites would be deployed.
Satellite deployment was scheduled for around 10:10 a.m., approximately 16 minutes after launch. Even after releasing its payloads, the rocket was expected to continue flying in order to collect additional data for analyzing the causes of the previous failure and evaluating the effectiveness of corrective measures implemented since then.
The H3 is Japan's flagship next-generation launch vehicle, developed by the Japan Aerospace Exploration Agency (JAXA) and Mitsubishi Heavy Industries to replace the highly successful H-IIA rocket, which carried out more than 45 launches over a period of more than two decades. The program was launched with the goal of reducing launch costs, increasing operational flexibility, and strengthening Japan's ability to compete in the growing global commercial space market while maintaining independent access to space.
Development of the H3 began in the 2010s as Japan sought a more affordable and versatile successor to the H-IIA. Engineers adopted a simplified design and newly developed LE-9 engines that burn liquid hydrogen and liquid oxygen. The rocket can be configured in multiple versions, allowing it to carry a wide range of payloads, from small satellites to large government and scientific missions.
The H3's debut proved challenging. Its first launch attempt on February 17, 2023, was halted just moments before lift-off when the rocket's second-stage systems failed to complete the final launch sequence. A month later, on March 7, 2023, the first H3 test flight lifted off successfully from the Tanegashima Space Center but ended in failure when the second-stage engine did not ignite as planned. Mission controllers issued a destruct command after determining the rocket could not reach orbit, resulting in the loss of the Advanced Land Observing Satellite-3 (ALOS-3).
Following an extensive investigation and redesign effort, the H3 returned to flight on February 17, 2024. The second test flight was a success, placing two small satellites into orbit and restoring confidence in the program. The achievement marked a major milestone for Japan's space industry and demonstrated that the issues responsible for the inaugural flight failure had been resolved.
Subsequent missions continued to build the rocket's track record. H3 Rocket No. 3 successfully launched the Advanced Land Observing Satellite-4 (ALOS-4) in July 2024, while later flights carried a variety of government and commercial payloads. The vehicle became an increasingly important part of Japan's space infrastructure, supporting Earth observation, communications, navigation, scientific research, and national security missions.
The program suffered another setback in late 2025 when H3 Rocket No. 8 failed to complete its mission. Investigators later concluded that shock loads generated during the separation of the payload fairing likely damaged hardware associated with the satellite mounting structure. The failure prompted JAXA and Mitsubishi Heavy Industries to suspend launches while engineers reviewed the design and implemented corrective measures.
The launch of H3 Rocket No. 6 on June 12 therefore carried significance beyond the delivery of its payloads. The mission served as a critical test of the modifications introduced after the No. 8 failure, particularly during the fairing separation phase that had been identified as a key factor in the earlier accident. The successful separation of the fairing and the rocket's continued flight along its planned trajectory provided an early indication that the corrective measures were working as intended.
Looking ahead, the H3 is expected to become the backbone of Japan's launch capability for the next two decades. The rocket is planned to support missions ranging from satellite launches and deep-space exploration projects to cargo deliveries for future lunar initiatives. As competition intensifies in the global launch market, the H3 is viewed as a cornerstone of Japan's efforts to maintain a strong presence in space while ensuring reliable and independent access to orbit.
Source: TBS
