Astronomy News
MMX Mission Profile: The Journey to Moon of Mars
The remarkable journey of Japan’s Martian Moons eXploration (MMX) mission is set to begin on October 20, 2026. With just five days to go before its scheduled launch, let’s follow along the carefully planned operations that await MMX at Phobos, where the spacecraft will collect surface samples for their return to Earth. These precious samples could hold vital clues to some of the long-standing mysteries surrounding Mars and its moons, helping scientists better understand their origins and the evolution of the Martian system.
ภาพ : JAXA
The mission is scheduled to launch on October 20, 2026, at around 4:41 a.m. Japan Standard Time, aboard Japan’s H3 rocket from Tanegashima Space Center. For MMX, the rocket configuration is H3-24L, described in the source as the most powerful H3 configuration, using four SRB-3 solid rocket boosters alongside the rocket’s LE-9 first-stage engines. The rocket is approximately 63 metres tall and weighs about 574 tonnes without its payload. After liftoff, MMX is expected to separate from the launch vehicle around 75 minutes later and begin its journey toward Mars.
The spacecraft will then travel along a transfer trajectory toward the Martian system, with arrival expected about a year after launch. Reaching Mars is only the beginning. MMX will need to adjust its path with engine burns to enter an orbit that allows it to operate near Phobos. Because Phobos has very weak gravity, it cannot hold the spacecraft in a conventional orbit around itself in the way a much larger body could. Instead, MMX is planned to use a Quasi-Satellite Orbit, or QSO, in which the spacecraft travels around Mars in a path that keeps it close to Phobos. From Mars, the spacecraft will appear to accompany the moon; from Phobos, its motion can look like an orbit around the moon.
Operating in this region requires careful planning. Mars, Phobos, Earth, and the Sun are constantly changing positions, affecting navigation, power, and communication. When the Sun lies between Earth and Mars during a solar conjunction, solar interference can make communication more difficult. Communication can also be interrupted when Mars or Phobos blocks the direct line of sight to Earth. During eclipses, when the spacecraft passes into the shadow of Phobos or the night side of Mars, its solar panels temporarily stop receiving sunlight. These constraints must be considered throughout the mission, especially during delicate surface operations. As a result, key landing activities are planned for a period when Mars is relatively close to Earth, helping reduce communication delays and other difficulties.
While travelling around Phobos, MMX will carry out detailed observations using a suite of scientific instruments. MEGANE, developed with NASA and research partners in the United States, will measure gamma rays and neutrons to help investigate the moon’s elemental composition. OROCHI will take wide-angle images in visible wavelengths, while TENGOO will capture high-resolution images of the surface and its landforms. MIRS, developed with contributions from France’s space agency CNES, will study near-infrared spectra to investigate surface composition. LIDAR will use laser pulses to measure the surface and help map its shape and elevation. Other instruments will study ions around Mars, dust in the Martian environment, and radiation conditions relevant to future exploration. A Super Hi-Vision camera, developed by JAXA and NHK, will also capture ultra-high-definition 4K and 8K images of Mars and its moons.
Before the main spacecraft attempts to collect a sample, MMX will deploy the IDEFIX rover, developed jointly by CNES and Germany’s aerospace centre, DLR. The rover will examine the surface and its properties, helping the team understand the local environment and support the selection of a suitable sampling site. MMX is planned to collect samples from Phobos during two separate operations, targeting surface areas that may differ in colour and origin. These samples could contain material native to Phobos as well as fragments of Mars ejected into space by ancient impacts, making careful analysis essential.
After completing its work at Phobos, MMX is also scheduled to make observations of Deimos, Mars’s smaller and more distant moon. The spacecraft is then expected to depart the Martian system by 2030. A return capsule carrying the collected samples is scheduled to land in Australia at around 2031, marking the final stage of the mission’s journey back to Earth. Researchers will be able to use instruments on Earth to examine the recovered samples in detail.
A mission spanning more than five years is no small feat, especially when every step brings a new challenge. Space exploration rarely comes without setbacks, and JAXA’s first Hayabusa mission is a testament to the challenges of deep-space exploration. The spacecraft encountered a series of problems, including malfunctioning ion engines and reaction wheels, a rover that lost contact, a sampling tool that failed to operate as intended, and a six-week communication blackout after the spacecraft tipped over on the asteroid’s surface. Despite these setbacks, the mission team managed to recover the spacecraft and return asteroid samples to Earth. The lessons learned from Hayabusa helped inform the development of its successor, Hayabusa2, further strengthening JAXA’s expertise in deep space sample-return missions.
This MMX mission could easily be the most daring mission to date. Nevertheless, Mars is the new frontier, and MMX will have to overcome numerous hurdles in order to get a sample from the Red Planet’s moon back to Earth. Stay tuned as we get closer to the launch of JAXA’s MMX mission and continue to support this extraordinary journey to Phobos.
Text: Rika Mei Reventar, Matipon Tangmatitham