Japan Launches $578 Million MMX Spacecraft to Bring Home Pieces of Phobos
Japan launched the Martian Moons eXploration spacecraft before dawn on October 20, 2026, opening a five-year campaign to achieve the first sample return from a Martian moon. The spacecraft lifted off aboard H3 Launch Vehicle No. 10 at 4:41 a.m. Japan time from Pad-2 at the Yoshinobu Launch Complex on Tanegashima island, or 3:41 p.m. EDT on October 19. Coverage of the flight, reported by outlets including Space.com, Ars Technica and Kyodo News, said the 207-foot-tall, 63-meter rocket flew a nominal ascent over the Pacific, shed its four solid boosters in pairs before the two-minute mark, and confirmed spacecraft separation about 71 minutes after liftoff. Controllers soon established contact, deployed the solar arrays, and declared the nearly 9,900-pound, 4.5-ton spacecraft in stable condition.
The Japan Aerospace Exploration Agency called the injection exceptionally precise. JAXA President Hiroshi Yamakawa said a five-year journey had just started, while project manager Yasuhiro Kawakatsu summed up the early hours as so far, so good. Japan's science minister Yoshihiro Seki described MMX as aiming for the world's first sample return from the Martian moons. The mission is led by JAXA with NASA, France's CNES, Germany's DLR and the European Space Agency. The H3, built by JAXA with Mitsubishi Heavy Industries, was making its 10th flight, its third straight success after the December 22, 2025 failure of flight No. 8, and its first payload beyond Earth orbit. The mission is reported at about $578 million.
Phobos, the larger of Mars' two moons, averages about 14 miles or 22 kilometers across, with a surface area comparable to Houston; Deimos is about 8 miles or 13 to 14 kilometers wide. Scientists disagree over whether the moons are captured asteroids or debris from a giant impact on Mars, and a returned sample would test the competing fingerprints against Martian rock and asteroidal material. After mapping campaigns, MMX is to touch down twice on Phobos in 2030 and gather at least 10 grams, or about 0.35 ounces, using two independent samplers: a JAXA corer that scoops material from about 2 centimeters down and a NASA pneumatic sampler that fires pressurized nitrogen to sweep dust into a canister. At least 15 percent of the sample goes to NASA for curation at Johnson Space Center in Houston; about one gram is to be released quickly for initial analysis, with the rest curated at JAXA's Sagamihara center.
MMX extends Japan's Hayabusa and Hayabusa2 asteroid sample-return lineage to the Martian system. It also picks up where failed efforts left off: Russia's Phobos-Grunt never left Earth orbit in 2011, and the Soviet Union lost two Phobos-bound spacecraft launched in 1988. The French-German Idefix rover, weighing 25 kilograms or 55 pounds, is to land on Phobos in late 2028 or early 2029 to scout landing sites and examine surface texture. The mission plan then calls for the mothership to leave the Martian system in November 2030 and send a capsule to a parachute landing at Woomera in South Australia in 2031. Reports note China's Tianwen-3, targeting launch around 2028, could deliver Mars samples as early as 2031, setting up a closely watched parallel timeline.
MMX cruises for about 10 months, arriving at Mars in August 2027 and entering quasi-satellite orbit near Phobos that September for roughly three years of science, including Deimos flybys. After the 2030 landings, the exploration module separates and the return module fires out of Mars gravitational influence for an eight-month cruise home. The launch itself was years late: MMX was originally meant to fly in 2024, but H3 development trouble forced a wait for the next Earth-Mars window, which opens only about every 26 months.