--- title: "Japan Launches MMX Mission: JAXA to Attempt Historic Phobos Sample Return" description: "Japan has launched the MMX spacecraft aboard an H3 rocket from Tanegashima. The $578 million mission is headed to Phobos, with Martian moon soil samples scheduled to return to Earth in 2031." date: 2026-10-20T12:23:57.803Z lang: en url: https://xab.info/en/posts/japan-launches-mmx-mission-to-mars-moons tags: [japan, jaxa, mars, phobos, mmx-mission, h3-rocket, space-exploration, sample-return] author: "Alexander Buran" publisher: "XAB.info" --- # Japan Launches MMX Mission: JAXA to Attempt Historic Phobos Sample Return ![Japanese H3 rocket carrying the MMX spacecraft flying against the backdrop of Mars and its moon Phobos](https://xab.info/media/2026/10/20/yaponiya-zapustila-missiyu-mmx-k-sputnikam-marsa/yaponiya-zapustila-missiyu-mmx-k-sputnikam-marsa-1.webp) ## Key Points - Japan launched the MMX spacecraft on an H3 rocket from Tanegashima Space Center on October 20, 2026, marking the country's heaviest interplanetary probe at 4.5 tons. - The Martian Moons eXploration mission costs $578 million, with arrival at Mars anticipated in August 2027. - In late 2028 or early 2029, the Franco-German rover Idefix will be deployed on Phobos, followed by two independent landings by MMX in 2029. - Samples weighing at least 10 grams are scheduled to return to Earth in a capsule landing in South Australia in 2031. - The mission aims to determine the origin of the Martian moons: whether they are captured asteroid belt bodies or impact debris. On October 20, 2026, Japan's flagship H3 launch vehicle lifted off from the Tanegashima Space Center in southern Japan, carrying the Martian Moons eXploration (MMX) spacecraft — the most ambitious space mission in the country's history. Valued at $578 million, the project's primary goal is to return soil samples from the surface of Phobos, the inner moon of Mars, for the first time in human history. The spacecraft is the heaviest interplanetary probe ever built in Japan, with a mass of 4.5 tons, two-thirds of which consists of propellant. To support the mission, the H3 launch vehicle was upgraded with an enhanced configuration featuring four solid rocket boosters and an enlarged payload fairing. ### Trajectory Insertion: 71 Minutes to Separation The rocket's upper stage accelerated the spacecraft to speeds exceeding 38,600 km/h, allowing it to escape Earth's gravitational pull. Seventy-one minutes after launch, MMX successfully separated from the launch vehicle, deployed its solar panels, and established stable communications with ground stations. The journey to the Red Planet will take 10 months, with arrival in the Martian vicinity expected in August 2027. In total, the spacecraft will spend about three years near the planet, performing a comprehensive set of scientific tasks. ### Quasi-Satellite Orbit and the Idefix Rover Phobos' weak gravitational field — less than one-thousandth of Earth's — combined with the powerful gravity of Mars itself, prevents MMX from entering a standard orbit around the moon. Instead, the spacecraft will maneuver along a so-called quasi-satellite orbit, requiring a series of precise maneuvers. The research will culminate in late 2028 to early 2029, when MMX will deploy the four-wheeled Idefix rover onto the surface of Phobos, developed jointly by the French and German space agencies. The Franco-German robot will operate on the moon for about 100 days, and later, in 2029, the main MMX spacecraft itself will perform two independent landings on the surface of Phobos. Scientists expect to collect at least 10 grams of material. ### What the Potato-Shaped Phobos Hides Phobos has a distinct potato-like shape with an average diameter of 22 kilometers. The scientific value of the MMX mission lies primarily in answering the question of the origin of the Martian moons: whether Phobos and Deimos are bodies captured from the asteroid belt, or debris formed as a result of Mars colliding with another celestial object. Furthermore, due to its proximity to Mars, dust kicked up by meteorite impacts on the planet itself has accumulated on the surface of Phobos for billions of years, meaning the collected samples may contain primordial traces of Martian soil, opening a unique window for studying the geological past of the Red Planet. ### The Return Journey: Capsule to Land in South Australia The return flight of MMX to Earth is scheduled for 2030. A special capsule containing the collected samples is expected to land at a testing range in South Australia in 2031. Thus, about five years will pass from launch to the return of the samples to Earth — a timeline JAXA considers the upper limit of the mission's five-year cycle. Successful execution of the project will make Japan the first country to retrieve extraterrestrial material from a body that is neither the Moon nor an asteroid, significantly expanding our understanding of the formation of satellite systems in the Solar System. ## Fact-Check & Sources - [578 миллионов долларов и 10 месяцев полета: Япония запустила уникальную миссию к спутникам Марса](https://www.rbc.ua/ukr/news/578-milyoniv-dolariv-ta-10-misyatsiv-polotu-1792491052.html) - The primary source contains all key facts: $578 million cost, 4.5-ton mass, 38,600 km/h speed, 71 minutes to separation, arrival in August 2027, Idefix rover (100 days), two MMX landings in 2029, at least 10 g of samples, capsule landing in South Australia in 2031. All data are consistent with each other. ## FAQ ### What is the MMX mission and who organizes it? MMX (Martian Moons eXploration) is an interplanetary mission by Japan's space agency JAXA targeting the Martian moons Phobos and Deimos. Its primary goal is to collect samples from the surface of Phobos and return them to Earth for the first time in history. ### What is the cost of the MMX mission? The Martian Moons eXploration project costs $578 million. ### When will the MMX spacecraft arrive at Mars? The journey to Mars will take 10 months, with arrival in the planet's vicinity expected in August 2027. ### What is the Idefix rover and who developed it? Idefix is a four-wheeled rover developed jointly by the French and German space agencies. It will be deployed onto the surface of Phobos in late 2028 or early 2029 and operate there for about 100 days. ### When will the Phobos samples return to Earth? The return flight of MMX is scheduled for 2030, with the sample return capsule landing at a range in South Australia in 2031. ### Why can't MMX enter a normal orbit around Phobos? Phobos' gravitational field is less than one-thousandth of Earth's, and Mars' gravitational influence dominates the region. Therefore, the spacecraft will travel along a so-called quasi-satellite orbit.