The mission will travel to
Mars and survey the red planet’s two moons; Phobos and Deimos.
The spacecraft will explore both moons and collect a sample
from one of the moons to bring back to Earth.

What’s MMX?

Martian Moons eXploration (MMX) is a Martian moons exploration project aiming for launch in the early 2020s. After launching from the earth, the spacecraft arrives in the Martian space over a period of about a year, and is entered into an orbit around Mars. After that, it will enter the Quasi Satellite Orbit (QSO) around the Martian moon, and get scientific data and samples from the Martian moon. After the observation and sample collection, the spacecraft will come back to the earth with samples taken from the martin moon. Currently it is assumed that it will be launched in 2024, Martian orbit insertion in 2015, and it will return to the earth in 2029.

By exploring the Martian moon, it is expected to improve technologies for future planet and satellite exploration such as, technologies required for roundtrip between the earth and Mars, the advanced sampling technique on the Martian moon surface, and the optimal communication technology using the deep space network ground station.

It is also thought that the origin of the two Martian moons and the process of the evolution of the Martian Sphere (Mars, Phobos, Deimos) can be clarified and the key to solve the mysteries of the planetary formation of the solar system can be obtained.


The purpose of MMX is

  • To identify whether Martian moons are captured asteroids or accumulated fragments caused by a massive crash into Mars, and acquire new knowledge on the formation process of Mars and Earth-type planets.
  • To clarify the mechanisms of the transition of the Martian moon and the Mars surface, and to get new knowledge to the evolutionary history of "Mars Sphere" including Martian moons.

"Knowing the origin and evolution of planets that lead to life" is an important scientific goal. For that reason, Mars, which once held a surface environment similar to the Earth with life, is an important exploration target.

Martian moons have sediments released from Mars for billions of years. By observing them, information on the evolution of the Martian surface can also be obtained. If Martian moons are made by collision of gigantic asteroids, the originating materials and formation process of Mars can be understood. If those are made by capturing a huge asteroid, transport process of volatile components (such as water) of the Earth-type planet can be clarified.

In other words, Martian moons exploration has important meaning not only in just knowing the martin moons but also in future planetary science.


To achieve the purpose of MMX, spacecraft needs to satisfy various requirements.
After separating from a launch rocket, the spacecraft needs to satisfy;

  • Important requirements to keep the spacecraft alive such as, electric power, heat, and communication with the earth.
  • Requirements from science instruments, such as altitude and timing of scientific observation.

In-depth studies are being conducted to design a spacecraft that meets these requirements.


In addition to collecting samples, MMX also performs remote sensing of Mars and its moons using various observation instruments.It is still not clear how the two small Martian moons were formed and what process they were going through. Phobos surface seen with visible / near infrared light is not uniform, and the possibility that the constituent materials are different is also discussed. Discussions are being made by Japanese and international scientists to determine where samples should be taken from. Observation data obtained by remote sensing instruments will be used to determine the sampling locations.


In MMX project, the spacecraft system team and the science team collaborated to form working teams to solve various difficult and challenging tasks. Additional working teams will be formed as necessary.

Landing Operation Working Team

LOWT is a team consisting of system and science experts to conduct research studies related to the Martian moons landing operation.

Science Operation Working Team

SOWT is a team consisting of system and science experts to conduct research studies related to science measurement operation.

Data Processing Working Team

A team to study issues relating ground data processing of mission data from the spacecraft