---
title: "Japan Sends MMX From Tanegashima to Take a Handful of Phobos and Bring It Home"
description: "JAXA’s $350 million probe will try to settle whether Mars’s moons are captured asteroids or wreckage, and return its samples in 2031"
author: "Jan Sokol"
published: 2026-10-19T21:42:23Z
modified: 2026-10-20T02:58:37Z
url: https://rews.cc/a/japan-sends-mmx-from-tanegashima-to-take-a-handful-of-phobos-793b8e
language: en
tags: ["space", "japan", "mars", "phobos", "jaxa", "asia"]
publisher: "Rews (https://rews.cc)"
---

# Japan Sends MMX From Tanegashima to Take a Handful of Phobos and Bring It Home

*JAXA’s $350 million probe will try to settle whether Mars’s moons are captured asteroids or wreckage, and return its samples in 2031*

By Jan Sokol · October 19, 2026 · https://rews.cc/a/japan-sends-mmx-from-tanegashima-to-take-a-handful-of-phobos-793b8e

## In brief

- JAXA launched the $350 million MMX probe on an H3 rocket from Tanegashima on 20 October Japan time (19 October in the US)
- The mission aims to find out whether Phobos and Deimos are captured asteroids or debris from a giant impact on Mars
- MMX is due in Mars orbit in 2027, will drop a Franco-German rover in 2029 and will land on Phobos around 2030 to collect at least 10 grams
- About 1% of the sample could come from Mars itself; NASA’s Mars Sample Return mission was effectively cancelled in January
- Japan’s only previous Mars probe, Nozomi, failed to enter orbit in 2003; the sample capsule is targeted to return in 2031

At 4:41 in the morning on Tuesday, 20 October, Japan time, an H3 rocket rose from the Yoshinobu Launch Complex at the Tanegashima Space Center. On the east coast of America it was still Monday afternoon, 3:41. On top sat the Martian Moons eXploration probe, MMX, which [William Harwood of CBS News](https://cbsnews.com/news/japan-launches-ambitious-robotic-mission-to-land-on-martian-moon-phobos-return-samples-to-earth/) put at $350 million. Its job is to reach the two moons of Mars, set down on the larger one, take a little of its ground and carry it back to Earth.

The official requirement is at least 10 grams, less than half an ounce. A probe weighing 9,900 pounds, ten months of travel out, three years of circling and a long flight home, all for a pinch of dust. Nobody has ever done it from the Mars system before. In science, it seems, the size of a prize has little to do with its weight.

## Two small moons

Phobos measures 17 miles across at its widest. Deimos is less than half that. Both are lumpy and irregular and look like asteroids, but looks settle nothing. Scientists are split, as [Ellyn Lapointe wrote for Gizmodo](https://gizmodo.com/japans-mission-to-snatch-a-sample-of-a-martian-moon-launches-today-heres-how-to-watch-2000827636), between two accounts of where the moons came from. In one, they are old asteroids that wandered too close and were caught by Mars’s gravity billions of years ago. In the other, they are what was left after something huge struck Mars and threw material into orbit, where it clumped together.

![An orange, cratered planet with a large broken section floats among asteroids and curved trails of debris against a dark, starry background.](https://rews.cc/img/53941b93506d099d576e8c5619b5d4854673e4cc.webp)

“One of the most intriguing questions about Phobos and Deimos is simply why these two little moons are there in the first place,” said Thomas Statler, NASA’s program executive and program scientist for MMX, who helped oversee development of the two NASA instruments on board. Some evidence points to the outer asteroid belt and some to a giant impact early in Mars’s history. Bringing Phobos material home, he said, would show which of the two it resembles more. In a statement he went further: knowing how the moons were born “will help illuminate that early era when Earth and the other inner planets may have been acquiring much of their water and organic compounds.”

## The road out

Four solid-fuel boosters and two hydrogen-burning main engines pushed the rocket through the thick lower air. Then the second stage took over and fired twice. According to [JAXA’s launch statement](https://global.jaxa.jp/press/2026/10/20261020-1_e.html), the spacecraft separated about 71 minutes and 13 seconds after liftoff and reached its planned orbit, with H3 flight No. 10 behaving as intended.

The schedule after that is long. JAXA’s [mission update](https://mmx-news.isas.jaxa.jp/?p=2753) has MMX arriving in Mars orbit in August 2027 and settling into its orbit around Phobos in September, when CBS expects the braking manoeuvre that puts it in lockstep with the moon. For three years it will point its instruments at Phobos: the chemistry and minerals of its surface, the space around it, and whether astronauts might one day use it as a base.

![A satellite with solar panels scans a cratered lunar surface with a pale green beam against a dark, starry sky.](https://rews.cc/img/ac5f0ec57ddc1769d16322d9f1398ae4cdd19ffc.webp)

In early 2029 it will drop a 55-pound rover supplied by the German and French space agencies, which [ESA identifies as Idefix](https://www.esa.int/ESA_Multimedia/Images/2026/10/The_Martian_Moons_eXploration_MMX_mission). The rover has no braking rockets. Phobos pulls with one-thousandth of Earth’s gravity, so the rover is expected to bounce and tumble gently to a stop, turn itself upright however it lands, and set off. It carries cameras to steer by and to look at the soil, a laser that fires into the ground to identify minerals, and a soil thermometer.

About a year later, around 2030, the mothership will land once, and perhaps twice, at different spots. One sampling device is JAXA’s. The other, supplied by NASA, was built by Honeybee Robotics. On the [mission’s own site](https://www.mmx.jaxa.jp/en/) the methods are described plainly: a corer that drills 2 centimetres down, and a pneumatic sampler that kicks loose surface material with pressurised gas. MMX will then leave, study Deimos from a distance without landing, and head home. A heat-shielded capsule is due to come down over Australia, where a recovery team will be waiting. JAXA’s target is 2031, but Gizmodo cautions that the date is not certain.

## Mars by the back door

There is a quiet second prize. Whatever their origin, the moons are probably coated in debris blasted off Mars itself. Kiyoshi Kuramoto of Hokkaido University, who leads the mission’s international science team, told *Science* that 1% of what MMX collects could come from the planet. “This is not going to be just a Phobos sample return mission,” Kris Zacny of Honeybee Robotics told the same journal. “It’s going to be Phobos and Mars.”

![Tweezers hold a small red fragment above dark rocks and powder in a shallow glass dish, rendered in a textured teal and cream illustration.](https://rews.cc/img/74146c93106e03c899da08fd87014a12dea335b4.webp)

That matters because of what happened to the grander plan. NASA’s Mars Sample Return mission was effectively cancelled in January, and dozens of rock cores collected by the Perseverance rover are left sitting on the Martian surface with no ride home. [CNN noted](https://www.cnn.com/2026/10/19/science/japan-mmx-mission-mars-moons) that if the Phobos samples contain fragments of Mars, MMX could be the first mission to deliver Martian material to Earth, in a race with China. Washington, meanwhile, has been shifting its planetary money and attention elsewhere: just last week it [moved its Venus probe launch forward](https://rews.cc/a/nasa-moves-up-venus-probe-launch-to-2030-and-funds-radar-orb-18ec27). One could say that history sometimes passes the expensive cathedral and arrives through the small side door. That is a reflection, not a forecast. The capsule still has to make it to Australia.

## Nozomi’s shadow

Japan has been to Mars once before, and it ended in failure. Nozomi, the country’s first interplanetary spacecraft, launched in July 1998. A faulty valve and then solar-flare damage cost it years. In December 2003, when the attempt to steer it into orbit failed, it was abandoned. In the words of [JAXA’s institute for space science](https://www.isas.jaxa.jp/en/missions/spacecraft/past/nozomi.html), it became “an artificial planet that flies forever in orbit around the Sun near that of Mars.”

MMX is the hardest thing JAXA has tried: reach the Martian system, land on a tiny moon with rough ground and almost no gravity, take off again, and come home. The agency’s case rests on its two Hayabusa missions, which brought back samples from small rocky bodies, though nowhere near this far away.

“MMX will be the first spacecraft ever to return to Earth from the Mars system,” Statler said. For him the best moment lies at the very end, when the capsule comes back through the atmosphere and is opened, “seeing those materials for the first time.”

## Sources

- [Japan launches mission to land on Martian moon Phobos and return samples](https://cbsnews.com/news/japan-launches-ambitious-robotic-mission-to-land-on-martian-moon-phobos-return-samples-to-earth/) — cbsnews.com
- [Japan’s Mission to Snatch a Sample of a Martian Moon Launches Today. Here’s How to Watch](https://gizmodo.com/japans-mission-to-snatch-a-sample-of-a-martian-moon-launches-today-heres-how-to-watch-2000827636) — gizmodo.com