Remote Woomera Set to Receive Phobos Samples in Japan-Led Mission to Probe Mars and Earth's Origins

A small capsule of rock and dust from a moon of Mars is expected to come down in the South Australian outback in 2031, and the town that will receive it is Woomera. The material is being gathered by a Japanese spacecraft that is already on its way to Mars as part of the Martian Moons eXploration mission, known as MMX.

The plan is specific. In roughly three years, the spacecraft is due to land on Phobos, the larger of Mars' two moons, drill into the surface and collect about 10 grams of rock and dust, the kind of loose surface material scientists call regolith. That is about a teaspoonful. The craft will then head back toward Earth, with touchdown set for Woomera in 2031.

Japan's space agency, JAXA, is leading the mission. The spacecraft carries a rover developed by the French and German space agencies. Dr Brandon Mahan, a University of Melbourne geochemist involved through a research partnership with JAXA, told Yahoo News Australia the mission is unlike any other in human history. He pointed to one distinction in particular: it will be the first to return samples from a moon other than Earth's own. He also said the engineering needed to pull it off is groundbreaking in its own right.

The scientific question at the centre of it is where Phobos came from. Dr Mahan explained that there are two theories. In one, Phobos began as an asteroid that Mars captured with its gravity. In the other, it formed from a giant impact in the past, a process comparable to the way Earth's moon is thought to have formed. Studying the material directly, rather than relying on remote observation or Martian meteorites, is meant to give what he called the most pristine picture of how the moon formed. That in turn could shed light on the formation of Mars and other terrestrial planets, Earth among them.

There is a second prize as well. Dr Mahan said impacts on Mars have thrown surface material into space, so a small fraction of the particles on Phobos should have originated on Mars. If researchers can find these "needles in the haystack," they could study pristine Martian surface material too, making the trip, in his words, doubly worthwhile. Such findings could also tell scientists more about what Mars is made of, which may matter for future missions as researchers consider humans travelling to, and eventually living on, Mars and other planets.

Woomera was chosen for its remote location, flat landscape and generally clear, dry weather, which make it well suited to spacecraft landings. The area has a long history of supporting space missions, and the project strengthens Australia's ties with Japan.

Once the sample is back, it will be shared with laboratories around the world, including the University of Melbourne. The hard part, Dr Mahan said, is that researchers are already working on ways to analyse the material without contaminating it, which he called a key challenge to overcome.

He said what excites him most is how long the project runs. Scientists are collaborating over many years, sharing knowledge and training the next generation of researchers who will eventually study the samples. For now, the spacecraft is still travelling to Mars, with the Phobos landing about three years away and the return to Woomera set for 2031.