Mission Overview・Mission Flow

Mission Overview

MMX (Martian Moons eXploration) is a mission to explore Martian moons.
Mars has two moons called Phobos and Deimos. MMX is planning to collect the surface material of a Martian moon and bring it back to the earth (sample return). MMX is currently under development to be launched by a rocket in middle 2020s.
The figure on the right is the image CG of Phobos.

Mission Flow

About one year after launch, MMX will arrive at Mars. After that, MMX will enter an orbits (Quasi-Stationary Orbit: QSO) which fly around the Martian moon and perform various observations. The period of staying in the vicinity of Martian moon will be decided by on-going studies such as observation planning. After observations and sample collection, MMX will return to the earth in about a year and delivers the collected samples to the earth.

Mission Objective

The MMX has the following objectives defined from two different aspects; science and engineering.


  • The origin of the Martian moons and process of formation of planet in the solar system are clarified.
  • The evolution process of the Martian-sphere (Mars, Phobos, Deimos) is clarified.


  • Technologies required for the return trip between the Earth and the Mars are established.
  • Advanced sampling techniques on celestial bodies are established.
  • Optimal communication technologies using a newly developed ground station is established.

Expected Outcomes

As the origin of the Martian moons, there are two dominant theories that (A) an asteroid was captured after the formation of Mars, (B) fragments scattered by a giant collision (Giant Impact) on Mars were accumulated. Based on the results of proximity observations and analysis of collected samples, it will be clarified which theory is a most likely one.
Through observation of Mars and its surrounding space from the vicinity of Martian moon, the mechanism of atmospheric material circulation and dissipation related to Martian surface environment and climate change. Together with these scientific achievements, MMX can contribute to achieving the great goal of "Understanding the evolution of the pre-life environment as a condition leading to the birth and sustenance of solar system life environment" in the field of planetary science research.