H2A Rocket Retires, Capping 25 Years of Excellence

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Japan's flagship heavy-lift rocket, the H2A, concluded its distinguished career with the successful launch of its 50th and final mission at 1:33 AM on June 29 from the Tanegashima Space Center in Kagoshima Prefecture. Roughly 16 minutes after liftoff, the rocket deployed the national Earth observation satellite Ibuki-GW into its designated orbit. It marked a flawless end to the H2A's service.

Developed by the Japan Aerospace Exploration Agency (JAXA) and Mitsubishi Heavy Industries, the H2A first entered operation in 2001. Over its 24-year run, it recorded 49 successes out of 50 launches, achieving a world-class cumulative success rate of 98.0%. With this final flight, the H2A officially retires. It now hands over its role as Japan's primary launch vehicle to the next-generation H3 rocket, which debuted in 2023.

From Failure to World-Class Success

The H2A is a two-stage, liquid-fuel launch vehicle measuring approximately 53 meters in length and 4 meters in diameter. Serving as Japan's primary national rocket, it has been entrusted with critical missions, particularly in the field of national security.

Throughout its operational life, the H2A completed 50 launches, carrying a diverse range of payloads into space. These included Hayabusa2, which famously returned rock samples from the asteroid Ryugu, SLIM, Japan's first successful lunar lander, and a series of intelligence-gathering satellites for government use.

Its early performance was strong, with the first five launches completed without incident. However, in November 2003, the sixth mission ended in failure after a solid rocket booster failed to separate at high altitude. That problem forced ground control to issue a self-destruct command.

The failure deeply shook the development team, prompting an exhaustive investigation into its cause. Engineers implemented comprehensive countermeasures, overhauling not just the faulty booster system but the rocket's overall design. They worked relentlessly — through holidays and overnight shifts — to make the necessary improvements.

Their dedication paid off with the successful launch of the seventh unit in 2005. From that point forward, the H2A maintained a perfect record, ultimately achieving a remarkable cumulative success rate of 98.0%.

The Standard for Precision

Beyond reliability, the rocket also delivered exceptional punctuality. Excluding delays caused by weather, it achieved an on-time launch rate of 82.0%, one of the highest in the world, meaning that most missions lifted off precisely as scheduled without mechanical issues.

*H2A Launch Vehicle No. 50 being launched from the Tanegashima Space Center in Kagoshima Prefecture, June 29.*

This outstanding track record allowed the H2A to serve as a pillar of Japan's space program for 25 years. Through disciplined engineering and a culture of continuous improvement, Japan's space industry turned early setbacks into a technological triumph, producing a rocket now regarded as a benchmark of precision and reliability.

A Legacy That Lives On

With 50 launches over a span of 25 years, the H2A holds the longest service record in the history of Japanese rocket development.

Its longevity was made possible by its exceptional reliability. Heavy-lift rockets carry satellites and probes that often cost billions, or even hundreds of billions of yen (several billions of US dollars). Such valuable payloads demand a launch vehicle with a proven, consistent track record, which the H2A delivered.

Even so, its operational run is coming to a close amid intensifying global competition. Each launch cost approximately ¥10 billion JPY ($63 million USD) — half the price of its predecessor, the H2. However, that was still nearly twice as expensive as competing rockets from abroad.

Considering that the H2A was designed more than 25 years ago, its relatively high cost is understandable. However, in today's increasingly competitive space industry, reliability alone is no longer enough. To remain viable in the global launch market, Japan has shifted to the H3 rocket, an evolution of the H2A that retains its trusted reliability while incorporating modern technologies to reduce launch costs to around ¥5 billion ($31.5 million).

Over its long career, the H2A showcased Japan's engineering excellence and earned a global reputation for precision and dependability. That legacy now serves as a foundation for the H3, positioning it to secure launch contracts both at home and abroad. Although its service has ended, the H2A leaves behind a profound and lasting impact. It is an enduring symbol of Japan's technological capability and space ambitions.

Author: Juichiro Ito, The Sankei Shimbun

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