The H3 flagship rocket is designed to replace the H-IIA after more than two decades in service.
The H3 had a “successful liftoff” at 9:22am Tokyo time (12:22 GMT) on Saturday and entered its planned orbit carrying a dummy satellite and two functioning microsatellites, the Japan Aerospace Exploration Agency (JAXA) said in a live broadcast.
Employees at the JAXA command centre cheered and hugged each other during the broadcast as the rocket reached its trajectory and released its first payload.
The H3’s microsatellites are expected to assist with disaster prevention efforts and monitor the operation conditions of factories.
JAXA is scheduled to hold a press conference on the launch later on Saturday.
The H3, billed as Japan’s flexible and cost-effective flagship rocket, was designed to replace the H-IIA, which has been in service since 2001.
The H3, which was developed with Mitsubishi Heavy Industries, is designed to carry a 6.5 metric tonne payload into space for as little as five billion yen ($33m) per launch, about half the cost of its predecessor.
JAXA hopes that the H3’s lower costs and greater payload capacity will attract global clients for missions, such as delivering supplies to the International Space Station and supporting the US-led Artemis moon exploration programme.
Tokyo has said it intends to launch about 20 satellites and probes with H3 rockets by 2030.
The H3’s successful launch follows back-to-back failures last year, including a botched launch in March that ended with ground control utilising the rocket’s self-destruct function shortly after blast-off after the second-stage engine failed to ignite.