H3 launch vehicle has been developed to replace H-IIA and H-IIB as Japan's flagship launch vehicle (rocket). The first flight of H3, launched in March 2023, failed due to the second stage engine ignition failure. However, after investigating the cause and implementing necessary countermeasures, the second through fifth vehicle have been launched successfully. As of September 2025, a new configuration for H3, featuring different numbers of the first stage main engines and the solid boosters, is undergoing final preparations for its first launch. Furthermore, plans to upgrade H3 launch vehicle in a step-by-step manner, to enhance its value to satellite operators and make it the internationally preferred launch service, are underway.
