Japan to Launch Ambitious Mission to Return Sample from Mars Moon Phobos

MMX spacecraft aims to solve the origin of Phobos and Deimos, with sample return expected in 2031

By LineZotpaper

Published19 October 2026

Read Time2 min

Sources3 outlets

The Japan Aerospace Exploration Agency (JAXA) is poised to launch the Mars Moons Exploration (MMX) mission on Monday, aiming to retrieve a pristine sample from the Martian moon Phobos. If successful, it will be the first mission to return material from the Mars system, potentially solving the long-standing mystery of how the Red Planet acquired its two small, irregular moons.

The spacecraft is scheduled to blast off from the Tanegashima Space Center on 20 October.

Upon arrival in the Mars neighbourhood in August 2027, MMX will first study the smaller moon Deimos before focussing on Phobos. The mission will attempt to land a small rover on Phobos, a feat Prof Sara Russell of the Natural History Museum, the mission's deputy for sample analysis, described as incredibly difficult. "No one has ever landed a rover on such a small moon," she told the BBC, explaining that the moon's own low gravity and the proximity of Mars's much stronger gravitational pull make the descent extremely challenging.

The rover will survey the surface to identify a safe landing site. The MMX spacecraft will then touch down, deploying a robotic arm to collect roughly 10 grams of dust using two samplers. This material will be sealed in a capsule and returned to Earth, landing in the Woomera desert of South Australia in 2031.

The mission's central scientific question is whether Phobos and Deimos are captured asteroids from the outer Solar System or debris formed from a massive impact on Mars early in its history. Prof Russell stated that the sample's chemistry will directly answer this question. "It should be pretty much immediately obvious," she said.

Dr Chrysa Avdellidou from the University of Leicester, also working on the mission, emphasized the value of the small sample. "You don't need to have kilos back from a surface in order to do science," she said. "So it's worth every gram."

A potential additional prize is the presence of Martian grains within the Phobos sample. Material blasted off Mars by impacts could have become embedded in Phobos, giving scientists access to pristine Mars material. This ambition has become more acute given the recent effective cancellation of the NASA/ESA Mars Sample Return mission, which would have collected samples being gathered by the Perseverance rover. China has its own Martian sampling mission planned for launch in 2028.

Analysis

Why This Matters

The MMX mission represents a first: the return of material from the Martian system, offering a unique window into the planet's geological history.
Its success would provide a significant boost to planetary science after the setback of the cancelled NASA/ESA Mars Sample Return mission.
The mission showcases JAXA's growing capability in deep space sample return, following its successful Hayabusa and Hayabusa2 asteroid missions.

Background

The origin of Mars's moons has been debated for decades. The two main theories are the capture of passing asteroids or the formation from debris after a giant impact. MMX was designed specifically to settle this. The mission faced unique engineering challenges: landing on a low-gravity body near a planet with strong gravity requires precise navigation. The return of the sample capsule to Woomera, South Australia, will be a major event for Australian space activities.

Key Perspectives

[Planetary Scientists]: Eagerly awaiting the sample to test the competing formation hypotheses. The potential presence of Martian dust offers an unexpected bonus pathway to study Mars directly.

[JAXA and Mission Team]: Focused on the complex choreography of orbital insertion, rover deployment, landing, and sample containment. Success would cement Japan's role as a leader in sample return science.

[Global Space Community]: Watching closely. The cancellation of NASA/ESA's sample return makes MMX the primary hope for pristine Martian material in the near term, although China plans a competing mission.

What to Watch

The success of Monday's launch and the health of the spacecraft during its cruise to Mars.
The rover's landing on Phobos, a technically challenging first for a moon of such size and gravity regime.
The security of the sample containment and the capsule's return to Earth through the atmosphere.
Whether the sample analysis reveals an asteroidal or impact origin for Phobos, and whether it contains grains of Mars.

Sources

Mission set to blast off for Mars to grab a piece of its moon · BBC News
Mission set to blast off for Mars to grab a piece of its moon · BBC News
Mission set to blast off for Mars to grab a piece of its moon · BBC News

Checked

12 claims in this story checked against 1 source: 9 supported.

Show each claim

SupportedA mission launching from Japan will attempt to return a sample from Phobos.BBC News: “A space mission is set to launch on Monday that will attempt to grab a piece of Mars's moon Phobos and bring it back to Earth. ... The spacecraft will blast off from Japan”
SupportedMMX aims to solve how Phobos and Deimos formed.BBC News: “It is hoped that the Mars Moons Exploration (MMX) mission, which is led by the Japanese Space Agency, will solve the mystery of how Mars's moons formed.”
SupportedThe sample capsule is expected to return in 2031 and land in the Woomera desert.BBC News: “This material will be packed into a small capsule that will return to Earth in 2031, landing in the Woomera desert of South Australia.”
Partly supportedThe mission is scheduled to launch on Monday, 20 October.BBC News: “The MMX mission is scheduled to blast off from the Tanegashima Space Center at 0441 local time on 20 October (2041BST 19 October).”
SupportedIf successful, MMX will be the first mission to return material from Mars or its moons.BBC News: “If it is successful, this will become the first time a sample has been returned from Mars or its moons to be analysed in laboratories here on Earth.”
SupportedThe mission aims to retrieve a pristine sample from Phobos.BBC News: “Scientists are so desperate to get their gloved hands on a direct sample from Mars and its moons because it would be pristine.”
Not in the sourcesRussell directly said, “No one has ever landed a rover on such a small moon.”BBC News: “Sara Russell says no one has ever landed a rover on such a small moon.”
SupportedRussell said, “It should be pretty much immediately obvious.”BBC News: ““It should be pretty much immediately obvious.. whether it's the product of this dramatic impact or whether it's a captured asteroid.””
SupportedAvdellidou said, “You don't need to have kilos back from a surface in order to do science” and “So it's worth every gram.”BBC News: ““You don't need to have kilos back from a surface in order to do science. So it's worth every gram,” she said.”
SupportedMMX is expected to arrive at Phobos in August 2027.BBC News: “The spacecraft will blast off from Japan and arrive at Phobos in August 2027.”
SupportedMMX plans to collect about 10 grams of material from Phobos.BBC News: “The amount of material that will come back is tiny - just 10g.”
Not in the sourcesThe effective cancellation of Mars Sample Return made the ambition to obtain pristine Martian material more acute.BBC News: “But a second Nasa/ESA mission, called Mars Sample Return, that would have picked up and returned these canisters, has been effectively cancelled, after its funding was halted by the US Congress.”