The Japan Aerospace Exploration Agency on Sept. 14 launched the Epsilon, Japan’s first new rocket in 12 years, putting the SPRINT-A planet-observation telescope into orbit some 1,000 km above the Earth. The telescope uses extreme ultraviolet rays to observe the atmosphere of planets.
The successful rocket launch represents the culmination of Japan’s solid-fuel rocket technology, which dates back to the tiny “pencil” rocket in the 1950s developed by the late Dr. Hideo Itokawa and his team. But JAXA and Japan’s rocket industry have a long way to go to make the Epsilon rocket competitive enough in the international market of commercial satellite launches.
In developing the Epsilon rocket, the JAXA team aimed at smaller size, lower costs and higher capabilities.
The three-stage rocket, which is 24.4 meters high and 2.6 meters across and weighs 91 tons, is about half the height of JAXA’s mainstay H-IIA rocket and is smaller than its predecessor M-5 rocket, which was retired in 2006 due to its high cost.
To lower the production cost, no new engines were designed. Instead, the Epsilon utilizes the H-IIA’s solid-fuel booster and parts of the M-5. But it makes full use of advanced IT technology.
About 100 people used to work in a large room to control the launch of a rocket. But in the launch of the Epsilon, only three were required to inspect the rocket with two personal computers. Artificial intelligence carried out autonomous pre-launch checks of the vehicle composed of numerous parts. This is an application of technology used in the machinery industry. The “mobile control” of a rocket launch was the first attempt in the world. The traditional control room near a launchpad became unnecessary.
In the past, it took JAXA 42 days from the time of setting up a rocket in a launchpad to the removal of related equipment after a launch. In the launch of the Epsilon, the period was shortened to seven days. Simplifying the procedure needed for a rocket launch is an important factor for facilitating a successful launch.
To reduce the weight of the Epsilon, light materials including carbon fiber was used in parts. JAXA successfully launched the rocket after three years of development. Thus Japan’s solid-fuel rocket technology was revived seven years after the M-5 rocket was retired. Seven M-5 rockets were launched from 1997 to 2006.
From now on, solid-fuel rockets will be launched from the Uchinoura Space Center and liquid-fuel rockets from the Tanegashima Space Center, both in Kagoshima Prefecture.
At ¥5.3 billion, the cost of the first Epsilon was about 70 percent of the cost of the M-5 rocket. JAXA hopes to reduce the cost to ¥3 billion by 2017. But it is not easy to compete in the international market. At the very least, JAXA will need to prove the reliability of the Epsilon rocket by increasing the number of launches. JAXA and Japan’s rocket industry must further improve the technology for easy-to-launch rockets.
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