Japan’s space agency JAXA launched the Martian Moons Exploration (MMX) probe on Monday, Oct. 19, marking the first sample‑return mission to the Martian system. The spacecraft lifted off from the Tanegashima Space Center aboard an H3 rocket at 3:41 p.m. EDT (4:41 a.m. local time). The launch, delayed from an earlier 2024 schedule due to concerns about the new rocket, began a roughly ten‑month cruise toward Mars that will span about 140 million miles.
Launch and journey to Mars
After separating from its fairing a little over an hour after liftoff, the camper‑van‑sized probe entered the “initial critical operations phase” on Oct. 21, confirming that its systems were functioning and that it was locked into its interplanetary trajectory. Naoki Murakami, general manager of Mitsubishi Electric’s space division, described the event as the first step of a five‑year mission.
MMX is an international effort, built with contributions from NASA, the European Space Agency and other partners. It will travel to Mars and arrive in August 2027, where it will enter a quasi‑satellite orbit around Phobos—circling the moon without being gravitationally bound, a configuration shared by several Earth‑bound quasi‑moons.
Landing strategy and sample collection
Once in orbit, the probe will spend several months gathering remote observations before attempting two separate landings on Phobos, the larger of the two Martian moons. The first landing will see MMX hover above the surface and deploy a miniature rover named Idefix, built by French and German agencies. Weighing about 55 lb (25 kg) on Earth, the rover will feel only roughly half an ounce (15 g) on Phobos because of the moon’s weak gravity.
After Idefix completes a surface assessment, MMX itself will touch down using a four‑legged lander module. Two of the legs house sampling tools: a drill and a pneumatic sampler (P‑Sampler) supplied by Honeybee Robotics for NASA. Kris Zacny, vice president of Honeybee Robotics, said the pneumatic device can collect material in “a matter of seconds.” The mission aims to retrieve about a third of an ounce (10 g) of Phobos material—roughly twice the amount gathered by JAXA’s Hayabusa2 asteroid mission.
Following sample acquisition, the probe will conduct close flybys of Deimos, the smaller moon, before beginning its return to Earth in late 2030. The spacecraft is slated to release its 20‑inch‑wide (60 cm) sample container for a splashdown likely in Australia in 2031.
Scientific objectives
Phobos and Deimos, discovered by Asaph Hall in 1877, remain enigmatic. Their origins are debated: some scientists propose they are captured asteroids or comets, while others suggest they formed from debris generated by a massive impact on Mars, similar to Earth’s Moon. Christopher Edwards of Northern Arizona University noted that orbital‑mechanics calculations make the capture scenario “quite hard.”
Project scientist Sonia Fornasier, an astronomer at the Paris Observatory, called the mission “a transformative leap” in studying the Martian system. She added that analyzing the returned samples could finally resolve the moons’ origins and offer clues about the early solar system, especially if the bodies contain organic or hydrated materials—a finding with significant astrobiological implications.
Beyond the moons, the mission promises insight into Mars itself. Tom Statler of NASA’s Planetary Science Division explained that understanding the moons’ formation will illuminate broader questions about planetary formation and the history of both Mars and Earth. If the moons are impact‑generated, the samples may even include fragments of Martian crust.
Space‑exploration experts, including Johns Hopkins Applied Physics Laboratory’s Nancy Chabot, emphasized that the Martian moons have been largely unexplored despite numerous Mars orbiters and rovers. MMX will fill that gap, delivering the first direct material from a Martian moon to Earth.
Helene Elliott is the Lead Science & Space Reporter at News Raise. She reports on aerospace missions, astrophysics discoveries, quantum research, and environmental technology.
