Japan Is Launching a Mission to Mars Moons and Plans to Bring Samples Home

An ambitious Mars mission is scheduled to launch Monday afternoon from the Tanegashima Space Center in Japan. Led by the Japan Aerospace Exploration Agency, with contributions from NASA, the Martian Moons eXploration mission could be the first to make it all the way to Mars and back. 

Not only will the mission send a spacecraft to study the Martian moons, Deimos and Phobos, JAXA and NASA aim to carry home samples from the surface of Phobos. JAXA set up a livestream so you can watch the historic launch, set for 3:41 p.m. ET.

“The samples from MMX will bring forth paradigm-shifting science on the Mars system for generations to come, especially as NASA prepares to send the first humans to Mars,” Nicky Fox, associate administrator for NASA’s Science Mission Directorate, said in an announcement. 

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By studying these Martian moons, scientists may learn more about how our own world came to be and why the solar system looks like it does today. 

The mystery of Martian moons

Many scientists believe that Earth’s moon was created long ago after one or more fast-moving objects from space collided with our planet, causing pieces to break off. This debris was captured by our planet’s orbit. Gravity collected it together over time and turned it into the rounded moon we know today. 

But it’s still a theory. Similar theories surround the origins of Deimos and Phobos. Scientists think Mars’ asteroid-sized moons might have formed through collision, like we think our moon formed, or the Martian moons might be asteroids that were captured in Mars’ gravity. 

By studying the moons close up, and then bringing samples home, scientists think they will be able to figure out how Deimos and Phobos came to be. 

“Having the answer will help illuminate that early era when Earth and the other inner planets may have been acquiring much of their water and organic compounds,” Tom Statler, MMX program executive and program scientist at NASA Headquarters, said in the announcement. 

Essentially, if we have more data on other moons, we’ll have a better understanding of how celestial bodies formed when our solar system was young. Studying the moons will also advance our knowledge of Mars’ surface and how the planet’s environment transitioned over eons. 

NASA’s contributions for the mission include the Mars-moon Exploration with Gamma rays and Neutrons (Megane) spectrograph instrument to study Phobos’ surface, as well as the pneumatic sampler (p-sampler) technology demonstration, which will collect the Phobos sample. NASA will also lend comms and navigation support with the agency’s Deep Space Network. 

A long way home

The mission will also test technology that could help humans travel to Mars one day. Getting a spacecraft to Mars and back, using robotics to reach and collect samples from the surface of Phobos, and relying on deep space communication the whole time should teach NASA and JAXA quite a bit about what it takes for a successful round trip to Mars. 

If all goes well, the mission will take five years. JAXA has scheduled the MMX spacecraft for a Mars arrival in August 2027. The craft will depart in November 2030, then arrive back home in July 2031. 

However, even if the MMX mission is a success, there’s no guarantee it will be the first mission to Mars and back. China’s Tianwen-3, tasked with returning samples from Mars to Earth, is scheduled for a 2028 launch, with a return date also set for 2031. 

In 2020, NASA’s Osiris-Rex spacecraft grabbed samples from the asteroid Bennu and brought them to Earth in 2023.

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Julian is a contributor and former staff writer at CNET. See full bio