A space mission is set to launch on Monday that will attempt to grab a piece of Mars’ moon Phobos and bring it back to Earth.
If it is successful, this will become the first time a sample has been returned from Mars or its moons to be analysed in laboratories here on Earth.
The spacecraft will blast off from Japan and arrive at Phobos in August 2027.
It is hoped that the Mars Moons Exploration (MMX) mission, which is led by the Japanese Space Agency, will solve the mystery of how Mars’s moons formed.
Prof Sara Russell, from the Natural History Museum, who is the MMX mission’s deputy for sample analysis, said: “There hasn’t yet been a successful mission to go to Phobos and bring a bit back to Earth.
“I think this is an incredibly ambitious and fun mission,” she said.
There are only three moons in the inner Solar System: our own Moon, and two around Mars, which are called Phobos and Deimos.
Both of these are tiny – Phobos is about 20km (12 miles) across and Deimos is about 10km (six miles) across. They are also irregularly shaped, looking a bit like space potatoes.
The MMX spacecraft will study Deimos as it arrives in the Mars neighbourhood, and then will focus on Phobos.
It plans to set down a small rover to explore the terrain, though this will be no easy feat.
Sara Russell says no one has ever landed a rover on such a small moon.
“The moon itself doesn’t have very much of its own gravity,” she explained.
“But it’s next to an enormous planet that’s got a much higher gravity, and that makes it much harder to get a rover onto the surface.”
The rover will scout out a landing site so that the MMX spacecraft itself can later touch down on Phobos.
Once on the surface, it will deploy a robotic arm and two samplers to grab some moon dust.
This material will be packed into a small capsule that will return to Earth in 2031, landing in the Woomera desert of South Australia.
The amount of material that will come back is tiny – just 10g.
“It’s a very small [amount] actually,” said Dr Chrysa Avdellidou, from Leicester University, who is working with the Japanese mission.
“However we can do several studies even on individual grains… You don’t need to have kilos back from a surface in order to do science. So it’s worth every gram,” she said.
Scientists believe the sample will finally shed light on the puzzle of where Mars’s moons came from.
There are two competing ideas.
