A Japanese-led space mission has set out on an ambitious journey to Mars’ moon Phobos, aiming to collect dust samples and return them to Earth for detailed scientific analysis. If successful, the mission could mark the first time material has been deliberately collected from a moon of Mars and brought back to Earth.
The Mars Moons Exploration (MMX) mission, led by the Japan Aerospace Exploration Agency (JAXA), is designed to investigate the origins of Mars’ two small moons, Phobos and Deimos, while potentially providing scientists with valuable clues about the history and composition of the Red Planet.
The spacecraft is scheduled to reach Phobos in August 2027. After studying the Martian moon, the mission will attempt to land on its surface, collect samples and return them to Earth in 2031.
The returning capsule is expected to land in South Australia’s Woomera desert, carrying approximately 10 grams of material gathered from Phobos.
Although the quantity is small, scientists believe even a few grams of extraterrestrial material could provide significant insights into planetary science.
MMX Mission Aims to Solve Mystery of Mars’ Moons
One of the mission’s primary objectives is to determine how Phobos and Deimos formed. Scientists have long debated the origins of the two moons, with two leading theories offering different explanations.
According to the first theory, a large space object collided with Mars billions of years ago, ejecting debris into orbit that eventually formed the two moons.
The alternative explanation suggests that Phobos and Deimos are asteroids originating elsewhere in the Solar System that were captured by Mars’ gravitational pull.
Researchers expect the material collected by MMX to help distinguish between these competing explanations.
Sara Russell, a professor at the Natural History Museum and deputy for sample analysis on the MMX mission, said studying the samples’ chemical and mineral composition could provide a clear answer.
She explained that the two theories would produce significantly different scientific results, potentially allowing researchers to determine relatively quickly whether the moons originated from a massive impact or were captured asteroids.
Russell described the mission as an ambitious and exciting undertaking, noting that no previous mission had successfully travelled to Phobos, collected material and returned it to Earth.
How the Spacecraft Will Collect Samples
After arriving in the Martian system, the MMX spacecraft will study Deimos before concentrating its efforts on Phobos.
The mission plans to deploy a small rover to examine the moon’s terrain and help identify a suitable landing location. The main spacecraft will subsequently attempt to touch down on the surface.
Once there, it will use a robotic arm and two sampling devices to collect dust and other surface material. The samples will then be secured inside a capsule for the journey back to Earth.
Landing on Phobos presents a considerable engineering challenge because of the moon’s unusual environment.
Phobos measures approximately 20 kilometres (12 miles) across, while Deimos is around 10 kilometres (six miles) in diameter. Both moons have irregular shapes and are often compared to space potatoes.
Their small size means they possess very weak gravitational fields, making it difficult for a spacecraft or rover to maintain stable contact with their surfaces.
Russell explained that Phobos’ proximity to Mars adds another complication. The much larger planet exerts a stronger gravitational influence, making it particularly challenging to manoeuvre a rover safely onto the moon.
The mission will therefore test technologies and operational techniques needed to explore small celestial bodies in complex gravitational environments.
Scientists Hope to Find Traces of Mars in the Samples
Beyond investigating the origins of Phobos, researchers are hoping the collected material could contain an unexpected scientific bonus: fragments of Mars itself.
Phobos orbits relatively close to the Martian surface. When asteroids strike Mars, they can eject rocks and dust into space. Some of this material may eventually travel far enough to become embedded in Phobos.
If the MMX mission retrieves such particles, scientists could examine material originating directly from Mars without having to collect every sample from the planet’s surface.
Russell said the possibility of finding Martian grains within the Phobos samples could provide valuable information about the planet’s composition and geological history.
The discovery would add another dimension to the mission, potentially allowing scientists to study both the moon’s formation and aspects of Mars’ past using a single collection effort.
Researchers also expect that analysing material returned directly from space will allow more precise investigations than are possible with many samples already available on Earth.
Why Direct Samples From Mars Matter
Scientists have long sought to bring Martian material back to Earth because laboratory facilities can conduct more detailed analyses than many instruments currently operating on spacecraft.
NASA’s Perseverance rover, which has been exploring Mars since 2021, has been collecting rock and soil samples and storing them in sealed canisters.
However, the planned NASA-European Space Agency (ESA) Mars Sample Return programme, which was intended to retrieve those containers and transport them to Earth, has effectively been cancelled following the loss of its funding in the United States.
China is also developing its own Mars sampling mission. The country plans to launch the mission in 2028, with the objective of returning Martian material to Earth in 2031.
Although scientists already possess fragments of Mars in the form of Martian meteorites, these rocks reached Earth naturally after being blasted off the planet by asteroid impacts.
Such meteorites are rare, and their scientific value can be complicated by contamination after they land on Earth, where they may come into contact with air, dust, soil and water.
Samples collected by a spacecraft and securely returned to Earth could offer a more controlled opportunity to investigate extraterrestrial material.
A Major Step Forward for Planetary Exploration
The MMX mission represents an important effort to answer fundamental questions about the formation of Mars’ moons and the evolution of the Martian system.
By collecting material from Phobos, examining the moon’s environment and potentially recovering fragments of Mars, scientists hope to gain new evidence about how these celestial bodies developed.
The planned return of samples in 2031 could give researchers access to material that has never before been studied directly in terrestrial laboratories.
If successful, the mission would mark a major milestone in space exploration and strengthen scientific understanding of Mars, its moons and the early history of the Solar System.
