WASHINGTON — As Japan prepares to join NASA’s Artemis lunar program, the country’s largest rocket manufacturer says it could upgrade the H3 rocket debuting next year to deliver cargo to the moon as soon as 2025.

Mitsubishi Heavy Industries’ deputy manager of space systems design, Shoyo Hyodo, said Oct. 25 that the successor to Japan’s H-2A and H-2B rockets remains on track for a 2020 maiden launch.

MHI is developing the H3 to be less expensive than its current launchers, in order to capture a bigger slice of the global launch market for commercial satellites while also meeting Japan’s military and civil launch needs.

H3 is slated to launch HTV-X, an upgraded cargo vessel, to the International Space Station in 2021, Hyodo said during a presentation at the 70th International Astronautical Congress here. To support NASA’s future lunar gateway, MHI is contemplating two variants of the H3 that could reach more difficult orbits, he said.

“MHI is considering how to do transfer missions to the Gateway and the lunar surface by upgrading H3 and HTV-X, step by step, [following] the development schedule and cargo supply needs,” of Artemis, Hyodo said.

H3 is designed to lift more than 7,900 kilograms to geosynchronous transfer orbit, Hyodo said. The rocket could, with an upgraded second stage, heft more than 3,400 kilograms of pressurized cargo and more than 1,000 kilograms of unpressurized cargo to the lunar Gateway space station using HTV-X, he said.

Launching an HTV-X cargo vessel to the gateway would require two H3 launches, he said. The first launch would send an HTV-X into an orbit around the Earth, he said. The second launch would send up an upper stage with an enlarged fuel tank to dock with the HTV-X and propel it to the Gateway, he said.

Hyodo said MHI could conduct such a mission in 2025 or 2026. NASA has been directed by the White House to achieve a crewed lunar landing by 2024. The agency is spearheading development of the lunar Gateway, with industry, as a nearby orbital outpost to reach that goal and support subsequent missions, though it is allowing companies to propose bypassing Gateway for initial landings.

Longer term, MHI could launch to the lunar Gateway or deliver landers directly to lunar orbit using a single rocket with three first-stage boosters strapped together, akin to United Launch Alliance’s Delta 4 Heavy or SpaceX’s Falcon Heavy, Hyodo said.

Hyodo said an H3 Heavy could send 11,900 kilograms to the lunar Gateway, 14,800 kilograms to geostationary transfer orbit, or 28,300 kilograms to low Earth orbit. The triple-core variant would also be well suited to bring rovers, habitation modules and other materials to the lunar surface, he said. H3 Heavy could be ready by 2030, he said.