TANEGASHIMA, October 19, 2026 — The Japan Aerospace Exploration Agency is launching the Martian Moons Exploration mission today, marking the first time a spacecraft has been designed to travel to the Mars system and return to Earth. This ambitious journey draws directly from the technical heritage of Japan’s previous asteroid sample-return programs to navigate the complexities of landing on the moon Phobos.
The Legacy of Hayabusa
The confidence behind the current mission rests on the operational history of the Japan Aerospace Exploration Agency, or JAXA. Formed in 2003 through the merger of the Institute of Space and Astronautical Science, the National Aerospace Laboratory of Japan, and the National Space Development Agency of Japan, the agency has spent decades refining deep-space navigation and retrieval. According to JAXA, the agency previously returned samples from the asteroids Itokawa and Ryugu via the Hayabusa and Hayabusa2 missions.
The Hayabusa mission successfully returned tiny particles from Itokawa in 2010, while Hayabusa2 deployed rovers on the surface of Ryugu and brought back more than 5 grams of material. These missions established the fundamental protocols for approaching small bodies in space, hovering near them, and executing a landing to collect surface samples. The Martian Moons Exploration mission, or MMX, scales these lessons to a more distant target. While previous missions focused on asteroids, MMX is the first spacecraft designed to travel to the Mars system and return to Earth, according to NASA program scientist Tom Statler.
Engineering the Martian Landing
The transition from asteroid exploration to the Martian moons requires a sophisticated approach to sample collection. The MMX spacecraft is scheduled to reach the Mars system in August 2027 and will land on Phobos no earlier than December 2028 to collect material. The landing sequence is designed to be brief, as the spacecraft will remain on the surface for approximately two and a half hours.
To ensure successful collection, the mission utilizes a dual-sampling system. JAXA’s C-Sampler is designed to extract core samples from a few inches beneath the surface. Complementing this, NASA has contributed a pneumatic sampler, known as the P-Sampler. According to Honeybee Robotics vice president Kris Zacny, the P-Sampler sits on one of the lander’s four legs and fires ultrapure nitrogen gas to blow loose soil into a container, effectively acting like a vacuum cleaner. This mechanical design ensures that both surface material and subsurface cores are secured for the return trip to Earth in 2031.
Collaborative Science and Objectives
The mission represents a significant partnership between JAXA and NASA, with the United States space agency providing technology and funding for participating scientists. NASA’s contribution includes the Mars-moon Exploration with Gamma rays and Neutrons, or MEGANE, spectrograph. According to NASA, the name is derived from the Japanese word for eyeglasses. The instrument will measure gamma rays and neutrons emitted from the moon’s surface to determine the chemical elemental composition of Phobos.
This data is essential for solving the long-standing mystery regarding the origins of Phobos and Deimos. According to NASA, scientists have debated whether these moons are ancient asteroids captured by Mars’ gravity or if they are debris blasted into orbit following a massive impact on the planet. Determining which scenario is correct will provide researchers with insights into the early history of the solar system, including how inner planets like Earth acquired water and organic compounds.
The partnership also extends to the handling of the returned material. NASA will receive and curate at least 15 percent of the returned samples at its Johnson Space Center Astromaterials Lab in Houston. According to Nicky Fox, associate administrator for the Science Mission Directorate at NASA Headquarters, this curation partnership is intended to support scientific research for decades to come. The total investment from the United States space agency is estimated at approximately $87 million over a 14-year period.
From Launch to Earth Return
The timeline for the mission is precise, beginning with the launch from the Tanegashima Space Center. Following the departure, the spacecraft will spend months transiting to the Mars system. Once it arrives, the mission will survey both Phobos and Deimos before committing to the landing on Phobos. The return journey is the final component of the mission, with the spacecraft expected to bring the samples back to Earth in 2031.
This mission builds on a history of Japanese space exploration that includes the SELENE lunar orbiter, the SLIM lunar lander, and the Akatsuki mission to Venus. By applying the techniques developed during the Hayabusa program to the Martian environment, JAXA aims to advance the understanding of the Red Planet. As Tom Statler noted, the fact that MMX will be the first spacecraft ever to return to Earth from the Mars system represents a significant step in planetary science. The data and samples collected will be shared for global research, continuing the collaborative effort to map the history of the solar system.
Sample Handling and Earth Return
After collecting material from Phobos, the MMX spacecraft will begin its return journey to Earth, with arrival expected in 2031. The returned samples will be divided between JAXA and NASA for scientific analysis, continuing a model of international collaboration established in previous missions.
NASA will receive and curate at least 15 percent of the returned Phobos samples at its Johnson Space Center Astromaterials Lab in Houston, ensuring long-term availability for research. This curation partnership is intended to support scientific studies for decades, building on the agency’s experience with extraterrestrial materials from Apollo, meteorites, and prior sample-return missions.
The shared analysis of these samples will allow scientists worldwide to study the composition and history of Phobos, contributing to broader understanding of planetary formation and the early solar system. As noted by NASA officials, the returned material holds potential to reveal insights into how inner planets like Earth acquired water and organic compounds over billions of years.
Sources
- JAXA's Martian Moons Exploration mission launch: how to watch live
- JAXA
- NASA to Help Unlock Mysteries of Mars’ Moons in Upcoming Mission – NASA Science
Photo: Osamu Iwasaki (CC BY-SA 2.0)
