Japan's MMX spacecraft to launch October 19 to collect samples from Mars moon Phobos

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The world just got its first good looks at some hardware that will make spaceflight history.

Last Thursday (Aug. 13), Japan unveiled the spacecraft that make up its Martian Moons eXploration ( MMX ) mission, which aims to snag samples of the Mars moon Phobos and haul them to Earth — something that has never been done.

The big reveal came at Tanegashima Space Center, the site from which MMX will launch toward the Red Planet atop an H3 rocket . And we just got some clarity about when that liftoff will take place.

Another look at MMX's Propulsion Module (back) and Exploration and Return Modules (front) at Tanegashima on Aug. 13, 2026. (Image credit: Yuichi YamazakiI/AFP via Getty Images) If all goes according to plan, MMX will launch on Oct. 19 at 3:41 p.m. EDT (1941 GMT; 4:41 a.m. on Oct. 20 Japan time), the Japan Aerospace Exploration Agency ( JAXA ) announced on Thursday (Aug. 20). That's the first day of the mission's launch window, which extends through Nov. 7.

JAXA originally intended to launch MMX in 2024 but had to stand down due to issues with the H3 . Mars and Earth align properly for interplanetary launches just once every 26 months, so this was a significant delay.

MMX will spend about a year traveling to Mars. Once in orbit around the Red Planet, the mission will map and study its two small moons, Phobos and Deimos , which are just 14 miles (22 kilometers) and 7.5 miles (12 km) wide, respectively.

Part of this work will help the mission team pick a landing site on Phobos, where they'll drop a 55-pound (25 kilograms) French-German rover called Idefix . That little robot — which is named after the dog in the French comic "Asterix" — will study Phobos' surface in detail using a variety of instruments.

The MMX spacecraft itself will then spiral down toward Phobos, eventually making contact and collecting about 0.35 ounces (10 grams) of material. MMX will leave Mars orbit with these samples in 2030 and deliver them to Earth for analysis a year later.

The mission aims to shed light on the nature and origin of Phobos and Deimos .

"Understanding how Mars and the two moons formed is a heavily debated topic in solar system science," JAXA officials wrote in a mission description .

"Remote-sensing observations by the MMX spacecraft and the detailed analyses of the returned sample will determine whether Phobos and Deimos are remnants of early Mars created from debris produced by a giant impact with the young planet, or whether the moons are asteroids captured by Mars's gravity that brought material from outer solar system ," they added.

To date, no spacecraft has returned material from the Mars system. Russia tried to do so with its Phobos-Grunt mission , which aimed to sample the eponymous Red Planet moon, but that effort failed shortly after its November 2011 launch. (The Soviet Union also launched two probes to Phobos in 1988, but neither one of them met its mission objectives.)

NASA plans to collect and haul home pristine samples that have already been collected on the Martian surface by its Perseverance rover , but it's unclear when or if that will happen. The agency has deemed its original sample-return architecture too expensive and is currently investigating other options.

There are good reasons to believe that Japan will succeed where others have failed, however. The country has a history of small-body sample-return success; its Hayabusa mission brought home pieces of the asteroid Itokawa in June 2010, and Hayabusa2 did the same with material from the space rock Ryugu in December 2020.