JAXA, the Japanese space agency

Chapter 1 · 1998 – 2003 Nozomi

Japan’s first planetary probe was meant to study the atmosphere of Mars. After five years of travel and a series of misfortunes, it passed the planet by.

An international probe

On July 3, 1998, an M-5 rocket launched the Nozomi probe from Kagoshima, designed by the Institute of Space and Astronautical Science, ISAS. It was Japan’s fourth deep-space probe and its first planetary spacecraft. It weighed 536 kilograms and carried fourteen instruments from Japan, Canada, Germany, Sweden and the United States. Its mission: long-term study of Mars’s upper atmosphere and its interaction with the solar wind, and tracking the oxygen escaping from the planet. It was to enter orbit on October 11, 1999.

The detour

To gain speed, Nozomi swung past the Moon on September 24 and December 18, 1998, then past Earth on December 20. But that Earth flyby did not give it enough velocity, and two trajectory corrections on December 21 used more propellant than intended. The whole mission had to be reconfigured: the probe would circle the Sun and reach Mars only in December 2003, four years late.

December 9, 2003

As it approached Mars, a malfunctioning part of the probe could not be restored, and communications were not re-established. On December 9, 2003, the Japanese space agency gave up placing Nozomi in orbit around Mars. The cause went back to April 2002: according to the Canadian Space Agency, which had provided one of the instruments, a very strong solar flare had caused a short circuit in one of the probe’s subsystems; according to the specialist press of the day, it had damaged its power system and communications. Nozomi passed about a thousand kilometers from Mars on December 14, 2003, then continued on its way around the Sun.

Sources: A. Siddiqi, Deep Space Chronicle, NASA SP-2002-4524 (launch on July 3, 1998 on M-5 from Kagoshima, ISAS, fourth deep-space probe and first planetary one, 536 kg, fourteen instruments and five countries, objectives, orbit planned for October 11, 1999, lunar and Earth flybys, corrections of December 21, 1998, arrival pushed back to December 2003); JAXA, “Topics 2003” (“JAXA gave up injecting Mars Orbiter ‘Nozomi’ into orbit of Mars,” December 9, 2003, malfunctioning part, communications not restored); Canadian Space Agency, “Canadian space milestones” (April 2002 solar flare and short circuit); S. Clark, “Japan’s star-crossed mission to Mars ends in failure,” Spaceflight Now, December 9, 2003 (abandonment on December 9, damage from the flare to power and communications, flyby at about 1,000 km); J. Uri, “25 Years of Continuous Robotic Mars Exploration,” NASA, 2022 (Mars flyby on December 14, 2003).

Chapter 2 · 2003 – 2031 JAXA and the Phobos gamble

Born from the merger of three organizations, the Japanese agency is returning to Mars by an original route: bringing back to Earth a sample of its moon Phobos.

A single agency

In October 2003, two months before Nozomi was abandoned, Japan merged its three aerospace organizations, the Institute of Space and Astronautical Science, the National Aerospace Laboratory and the National Space Development Agency, into a single agency: the Japan Aerospace Exploration Agency, JAXA.

MMX

The Martian Moons eXploration mission, MMX, is to be the world’s first to return material from the Martian sphere. The spacecraft will enter a special orbit around Phobos, called a quasi-satellite orbit, collect more than ten grams of samples, observe Phobos and Deimos, then return to Earth; the round trip and exploration are to take about five years, with arrival at Mars planned about a year after launch.

It is an international project led by JAXA. France’s CNES and Germany’s DLR provide a small rover, IDEFIX, handed over to Japan in March 2024; NASA signed a cooperation agreement in April 2023; ESA also takes part. In October 2022 the Australian and Japanese leaders supported in principle landing the sample capsule in Australia.

The spacecraft was delivered to the Tanegashima Space Center in April 2026. On August 20, 2026, JAXA set its launch, on the tenth flight of the H3 rocket, for October 20, 2026, at 4:41 a.m. Japan time, with a backup period until November 7. It is not without risk: on December 22, 2025, the eighth H3 flight had failed when the second-stage engine shut down prematurely on its second ignition.

Sources: JAXA, “History” (JAXA created in October 2003 by merging ISAS, NAL and NASDA); ISAS/JAXA, “Martian Moons eXploration (MMX)” page (first mission to return material from the Martian sphere, quasi-satellite orbit, observation of Phobos and Deimos, delivery to Tanegashima in April 2026, IDEFIX and the June 2023 JAXA-DLR-CNES agreement, rover handover in March 2024, agreements with CNES, DLR and NASA, Australia in October 2022); JAXA’s MMX website, via a search (more than ten grams, about five years, arrival a year after launch, participation of NASA, CNES, DLR and ESA); JAXA, release of August 20, 2026 (launch on H3 F10 on October 20, 2026 at 4:41:03, backup until November 7); JAXA, release of December 22, 2025 (failure of H3 flight No. 8). At the time of writing, October 11, 2026, the launch has not yet taken place.