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Solar System Mars Watch Japan launch a bold sample-return mission to Mars moon Phobos today News By Mike Wall Published 19 October 2026 The MMX mission is scheduled to lift off today (Oct. 19) at 3:41 p.m. ET (1941 GMT).

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Watch On Japan will launch an epic mission to Mars today (Oct. 19), and you can watch the action live.

The Martian Moons eXploration (MMX) mission is scheduled to lift off atop an H3 rocket from Japan's Tanegashima Space Center today at 3:41 p.m. EDT (1941 GMT; 4:41 a.m. on Oct. 20 local Japan time).

You can watch it live via the Japan Aerospace Exploration Agency (JAXA). Coverage will begin at 2:45 p.m. EDT (1845 GMT).

As its full name suggests, MMX will focus on Mars' two moons, Phobos and Deimos. They're both tiny compared to Earth's own moon; Phobos is just 14 miles (22 kilometers) wide, and Deimos is even smaller, with a diameter of about 8 miles (13 km).

Japan unveils Mars moon sample-return spacecraft ahead of Oct. 19 launch (photos) Japan launches historic MMX sample-return mission to Mars' moon Phobos (video) Returning the first samples from a Martian moon: Inside the science of Japan's bold MMX mission to Mars They're also quite mysterious. While astronomers have a pretty clear understanding of our own moon's birth - it coalesced from material blasted into space when a Mars-sized planet slammed into Earth long ago - there's no consensus about Phobos and Deimos' origin story.

The duo "may be the remains of a massive impact on Mars that sent material into orbit around the planet, or they could be ancient asteroids that were captured by Mars' gravity billions of years ago," Tom Statler, MMX program executive and program scientist at NASA Headquarters, said in an Oct. 15 statement. (NASA is a partner on the mission, providing a scientific instrument, a technology demonstration, communication support and funding for American scientists on the MMX team.)

MMX will help provide that answer, if all goes according to plan.

The spacecraft will arrive in the Mars system in August 2027, then slip into orbit around Phobos a month later. It will study that moon and Deimos from a distance for about 18 months, then deploy the French-German Idefix rover onto Phobos' surface in early 2029.

2 spacecraft headed to Mercury are about to begin their long-awaited arrival for Europe and Japan - watch it live today On this day in space! Sept. 13, 2007: Japan launches Kaguya spacecraft to the moon to map the lunar surface in HD China on track to launch Mars sample-return mission in 2028: 'If accurate, this represents a Sputnik moment' The 55-pound (25 kilograms) Idefix "has two main tasks: providing information to prepare for the landing of the main spacecraft to collect samples, and analyzing the composition and texture of Phobos' surface," European Space Agency officials wrote in an MMX mission description.

"The gravity on Phobos is so low that Idefix will only weigh the equivalent of 15 grams [0.5 ounces] on its surface!" they added.

The MMX mothership's Phobos landing will occur in 2030. The spacecraft will grab at least 10 grams (0.4 ounces) of samples from the moon, then head back toward Earth with this extraterrestrial bounty. MMX's return capsule will land here in 2031, after which scientists around the world will scrutinize the Phobos sample for clues about the history and evolution of Mars and our solar system more broadly.

MMX was originally supposed to launch in 2024, but issues with the H3 rocket prevented it from doing so. Mars and Earth align properly for interplanetary launches just once every 26 months, so MMX had to wait a while for its next chance.

Mike Wall Social Links Navigation Spaceflight and Tech Editor Michael Wall is the Spaceflight and Tech Editor for Space.com and joined the team in 2010. He primarily covers human and robotic spaceflight, military space, and exoplanets, but has been known to dabble in the space art beat. His book about the search for alien life, "Out There," was published on Nov. 13, 2018. Before becoming a science writer, Michael worked as a herpetologist and wildlife biologist. He has a Ph.D. in evolutionary biology from the University of Sydney, Australia, a bachelor's degree from the University of Arizona, and a graduate certificate in science writing from the University of California, Santa Cruz. To find out what his latest project is, you can follow Michael on Twitter.