"H3 Rocket No. 6" Launch Succeeds — "Low-Cost" Version Without Solid Boosters Makes Its First Flight

Explanation

On June 12, 2026, the sixth unit of JAXA's new large rocket "H3" successfully launched. This particular vehicle, called the "H3-30" configuration, increases the number of first-stage main engines from two to three, while omitting the solid rocket boosters that had been used until now. The aim of leaving out the boosters is to lower launch costs and make it possible to carry satellites into space more cheaply. This marks the H3's eighth flight overall, raising its success rate to about 75%.

For a rocket to break free of Earth's gravity and reach space, it needs an enormous velocity and the large quantities of fuel and thrust needed to produce it. Solid boosters can generate powerful thrust instantly once ignited, but they are expensive, and once they start burning they cannot be stopped. The technical highlight this time was the challenge of increasing the number of main engines and launching using only liquid fuel. The "law of action and reaction" learned in physics class—in which a rocket moves forward as a reaction to expelling gas backward—is being used directly at the frontier of space development.