Japan Aerospace Exploration Agency (JAXA)
The Japan Aerospace Exploration Agency (JAXA) is a national research and development agency in Japan that, driven by science and technology, aims to lead society and create value. JAXA carries out various activities from basic research to the development and utilisation of space technologies and aeronautics.
Recent JAXA highlights include the successful launch of the Global Observing SATellite for Greenhouse gases and Water cycle (GOSAT-GW) aboard the final H-IIA Launch Vehicle (No.50) in June 2025, bringing down the curtain on about a quarter-century of Its launch missions.
In the same month, DLR and JAXA celebrated the German National Day at the Osaka Kansai Expo with the special event “Beyond Planet Earth – German-Japanese Cooperation in Space.” It showed the close ties between Germany and Japan along with the ISS Astronaut Takuya Onishi’s message highlighting the importance of international cooperation taking place on the ISS.
New unmanned cargo transfer spacecraft1 (HTV-X1) made its debut flight aboard the 7th H3 Launch Vehicle (H3 F7) in October 2025. HTV-X1 was berthed to the ISS and cargo was successfully transferred to the ISS.
JAXA will continue to boost Japan’s activities in space and bring to life significant missions that contribute to the future of humanity.
Martian Moons eXploration (MMX) Mission
The world’s first sample return mission from the Martian moon, Phobos
The Martian Moons eXploration (MMX) mission is a project to explore the two moons of Mars and is planned for launch in one year. Approximately one year after leaving Earth, the spacecraft will arrive in Martian space and enter into orbit around the Red Planet. It will then move into a ‘Quasi Satellite Orbit’ around the Martian moon Phobos to collect scientific data and gather a sample from its surface. After making observations and collecting its sample of material from Phobos, the spacecraft will return to Earth. MMX is currently scheduled for launch in Japan Fiscal Year (JFY) 2026, followed by Mars orbit insertion in JFY 2027 and return to Earth in JFY 2031. The spacecraft is equipped with 13 instruments to investigate the two moons and the environment around Mars, with instrument contributions from NASA and the French Space Agency CNES.
MMX will also carry the IDEFIX rover developed jointly by the German Aerospace Center (DLR) and CNES. IDEFIX will explore the surface of Phobos before MMX lands to collect samples, providing in-situ data about the moon and substantially increasing the safety of the landing.
Exploring Mars’ moons will help improve technology for future planetary and satellite exploration, for example by advancing the technologies required to make round-trips between the Earth and Mars, advanced sampling techniques that will be employed on the Martian moon’s surface and optimising communication technologies using NASA’s Deep Space Network (DSN) of ground stations.
A major scientific goal for the mission is to clarify the origin of the two Martian moons and the evolution of the ‘Martian Sphere’ (Mars, Phobos and Deimos). MMX will also help elucidate the migration process of organic matter and water in the early Solar System and how they were supplied to celestial bodies.
H3 Launch Vehicle
Leading the world in space transportation
The H3 Launch Vehicle is Japan’s next-generation heavy-lift rocket. It has been developed as the successor to the H-IIA to continue transporting satellites, probes and other space-faring objects in a stable, safe manner.
Its first successful launch was on 17 February 2024, when the rocket (designated H3TF2 – H3 Launch Vehicle Test Flight No.2) flew as planned and completed all of its missions, including a second-stage orbit insertion, the separation of two piggyback satellites and a controlled re-entry.
The next launch, scheduled in June 2026, is a test mission of the “Type 30” configuration, featuring three LE 9 engines without solid boosters. It aims to reduce launch cost and improve flexibility. The vehicle will carry payloads including small satellites to demonstrate new technologies and flight performance.
In recent years, many satellites that directly impact our lives have been transported to space, and so utilising space has become part of our daily reality. In such a progressive society, the H3 aims to become a launch vehicle that attracts attention not only in Japan but also around the globe – as an easy-to-use space transportation system. To achieve this, JAXA is striving for H3 to be highly flexible, reliable and cost-effective.
JAXA offers two types of fairings, either two or three units for the first-stage engines (LE-9) and zero, two or four solid rocket boosters (SRB-3) to cope with various payload sizes and their orbits. The H3 can deliver a payload of at least 6.5 tonnes into geostationary transfer orbit, exceeding the capabilities of the H-IIA and H-IIB launch vehicle.
Main specifications
Length: 63m (Long type (L)), 57 m (Short type (S))
Core vehicle diameter: 5.2 m
Total mass (without payload): 575 t（H3-24L）
Fairing: Long type (L), Short type (S)
PAF diameter: 937 mm, 1194 mm, or 1666 mm
Launch capability
4 tonnes or even more to Sun-synchronous orbit (SSO)
6.5 tonnes or even more to geostationary transfer orbit (GTO) (ΔV=1500 m/s)
JAXA Public Affairs Department
E-Mail PROFFICE@jaxa.jp
