Japan Launches H3 Rocket to Capture Martian Moon Samples
The Japan Aerospace Exploration Agency successfully launched its Martian Moons eXploration spacecraft aboard an H3 rocket on October 20, 2026, beginning a five-year mission to retrieve rock and soil samples from Phobos, the larger moon of Mars. Lifting off before dawn at 04:41 local time from the Tanegashima Space Center in southwestern Japan, the uncrewed spacecraft separated from the upper stage of the rocket roughly 71 minutes later and entered its interplanetary trajectory toward Mars, detikInet reported.
The $578 million international mission brings together five space agencies, including NASA, the French space agency CNES, the German Aerospace Center DLR, the European Space Agency, and the Australian Space Agency, contributing instruments and deep-space tracking. The spacecraft carries 11 advanced scientific instruments designed to map the Martian moons and analyze their surface composition, according to reporting by Harapan Rakyat.
Japan has an opportunity to become the first country to land a spacecraft on Phobos and return samples. Jika seluruh tahapan berhasil, Jepang berpeluang menjadi negara pertama yang mendaratkan wahana di Phobos sekaligus membawa pulang sampel dari satelit alami tersebut. The United States and China are currently engaged in a parallel race to return rock samples from the Martian surface itself. NASA’s Perseverance rover has collected samples, though its Earth-return mission was stopped by the Trump administration following congressional budget votes in January, and China’s Tianwen-3 mission is slated to launch around 2028 with a potential sample return by 2031, which could rival the timeline of the Japanese return capsule.
MMX spacecraft will deploy Idefix rover near Phobos
The MMX spacecraft is scheduled to reach the Martian system in August or September 2027, where it will spend several months conducting detailed observations before entering a specialized quasi-satellite orbit around Phobos. Because Phobos is about 22.5 to 27 kilometers across and possesses extremely weak gravity—roughly one-thousandth that of Earth—maintaining a traditional circular orbit is mechanically unfeasible. Mission planners instead designed a synchronized flight path that matches the orbital speed of the moon.
In late 2028 or early 2029, the primary spacecraft will deploy a small, four-wheeled rover named Idefix, developed jointly by France and Germany and named after the white dog from the Asterix comic books, as detailed by detikInet. Due to the negligible gravity on Phobos, the 25-kilogram robot will hop across the irregular, cratered terrain rather than drive normally. Idefix will spend approximately 100 days examining surface textures, mapping mechanical properties, and assessing safety hazards to help the main lander select a secure touchdown site.
Lander will collect Phobos samples for Earth return
Following the reconnaissance phase by the rover, the main four-legged stationary lander will touch down on Phobos twice. The landing hardware will collect at least 10 grams of regolith and bedrock from two distinct locations. European Space Agency Mars Express imagery indicates that Phobos has a low density of roughly 1,860 kilograms per cubic meter, pointing to a highly porous interior structure likely formed from impact debris, according to Harapan Rakyat.
After acquiring the samples, the MMX mother craft will launch away from Mars orbit in November 2030, performing a close flyby of the smaller Martian moon, Deimos, to gather additional comparative data. The sample-return capsule is scheduled to detach and land in Australia in 2031. Planetary scientists plan to analyze the returned material to determine whether Phobos and Deimos are captured asteroids or native impact ejecta hurled into orbit by an ancient collision on Mars, providing vital baseline data for future human missions to the Red Planet.
Frequently Asked Questions About the MMX Mission
Why is Phobos the primary target instead of the Martian surface?
Phobos is the larger moon of Mars and is closer to the planet. Scientists believe samples from Phobos may contain ancient impact ejecta from the Martian crust, offering a way to study Mars geology without landing directly on the high-gravity planet.
What are the main theories regarding the origin of Phobos and Deimos?
Astronomers debate whether the two Martian moons are captured asteroids from the main belt or whether they formed from debris blasted into orbit by a massive asteroid impact on Mars early in the history of the solar system. The interior porosity measured by European orbiters supports the impact-debris hypothesis.
What happens if the MMX mission encounters mechanical failures like past Soviet attempts?
JAXA’s mission follows previous attempts, such as the Soviet Phobos 1 and Phobos 2 missions in 1988 and the Russian Fobos-Grunt mission in 2011, all of which failed before achieving their surface objectives. MMX utilizes international tracking support from NASA and the European Space Agency to minimize structural and navigational risks throughout its five-year timeline.
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