MMX (spacecraft)

MMX (spacecraft)
Name	MMX
Operator	Japan Aerospace Exploration Agency
Mission type	Robotic spacecraft
Launch date	2024, __, __
Launch vehicle	H-IIA
Launch site	Tanegashima Space Center
Mission duration	8 years (planned)
Destination	Phobos and Deimos

MMX (spacecraft) is a Japanese robotic sample-return mission developed by the Japan Aerospace Exploration Agency to visit the Martian moons Phobos and Deimos, collect surface samples, and return them to Earth. The mission links Japanese planetary science with international partners including the National Aeronautics and Space Administration, the European Space Agency, and research institutions such as the Institut de recherche en astrophysique et planétologie, aiming to address questions about Solar System formation, planetary migration, and the origin of water on Earth. MMX combines orbital operations, surface contact, sample acquisition, and interplanetary navigation using technologies matured on missions like Hayabusa2, BepiColombo, and Mars Reconnaissance Orbiter.

Overview

MMX was conceived by the Institute of Space and Astronautical Science within the Japan Aerospace Exploration Agency as part of Japan's strategic planetary exploration roadmap alongside missions such as Hayabusa and Hayabusa2. The mission's architecture integrates heritage from projects involving the Akatsuki atmospheric probe and the Kaguya lunar orbiter. MMX targets Phobos and Deimos to test competing hypotheses originally posed by researchers at institutions like the Observatoire de Paris and the Max Planck Institute for Solar System Research about whether Martian moons are captured asteroids or accreted impact ejecta from Mars, drawing on datasets from Mars Express and Viking program era studies.

Mission Objectives

Primary objectives include: 1) obtain pristine surface samples from Phobos and return them to Earth for laboratory analysis, 2) characterize the moons' geology, mineralogy, and volatile content to test origin models advanced by teams at California Institute of Technology, Massachusetts Institute of Technology, and University of Tokyo, 3) study the Mars–moon system's dynamical evolution in context with models from University of Colorado Boulder and Southwest Research Institute. Secondary objectives are technology demonstration for sample-return operations, comparative planetology with datasets from Mars Odyssey, Mars Global Surveyor, and to support future human exploration plans influenced by roadmaps from NASA and the European Space Agency.

Spacecraft Design and Instruments

The MMX spacecraft bus was developed by JAXA with contributions from industrial partners such as Mitsubishi Electric and NEC Corporation, and scientific payloads built by teams from CNES, DLR, and ISAS. Key instruments include the Mass Spectrometer for Planetary Exploration (MMX-P), a near-infrared spectrometer akin to payloads on Rosetta and Cassini–Huygens, a high-resolution camera comparable to instruments on Mars Reconnaissance Orbiter and Lunar Reconnaissance Orbiter, and a radar sounding instrument drawing heritage from SHARAD on Mars Reconnaissance Orbiter. The sampling system parallels mechanisms used on Hayabusa2 including a corer and landing leg assemblies informed by engineering at University of Tokyo laboratories. An onboard propulsion system leverages xenon electric propulsion tested on missions like Dawn and chemical propulsion with components from IHI Corporation.

Launch and Trajectory

MMX launched on an H-IIA vehicle from Tanegashima Space Center using a trajectory incorporating Earth- and Mars-transfer windows refined through trajectory analysis expertise at JAXA, NASA/JPL, and ESA navigation teams. Cruise phase navigation borrows techniques validated by Voyager program, Parker Solar Probe, and Hayabusa for deep-space maneuvering and optical navigation using star trackers supplied by contractors with heritage from the European Space Operations Centre. The planned interplanetary trajectory includes Mars flybys and phasing orbits culminating in Mars system insertion similar to strategies used by Mars Express and MAVEN.

Operations and Science Campaigns

Operational control centers at JAXA coordinate science campaigns with international science teams from institutions such as University of Paris-Saclay, Massachusetts Institute of Technology, University of Bern, and Chinese Academy of Sciences collaborators. Surface reconnaissance will employ imaging campaigns inspired by methods developed for Hayabusa2 touchdown planning and NEAR Shoemaker operations, while spectroscopic surveys will reference calibration standards from International Astronomical Union working groups and comparative data from Dawn at Vesta and Ceres. Radio science experiments will probe Phobos' gravitational field drawing on techniques used by Cassini and Galileo; sample-site selection will integrate geological mapping approaches from Lunar Reconnaissance Orbiter and rover mission experience such as Curiosity and Perseverance.

Sample Return and Analysis

The sample-capture system aims to retrieve regolith and possible subsurface materials in a campaign coordinated with curation facilities modeled after NASA Johnson Space Center and the European Sample Curation Facility. Returned samples will be distributed to laboratories including the Smithsonian Institution, Natural History Museum, London, and university facilities at University of Tokyo and Caltech for isotopic, mineralogical, and organic chemistry analyses to test hypotheses from proponents at Brown University and University of Arizona. Results are expected to impact models of volatile delivery to terrestrial planets debated in workshops at AGU and EPSC-DPS conferences and to inform future missions by agencies including JAXA, NASA, and ESA.

Category:Japanese space probes