Plenty of spacecraft have orbited and even landed on the surface of Mars. But the red planet's twin moons have remained untouched – until now.
A mission led by Japan's space agency aims to become the first to return a piece of a Martian moon. And now, the spacecraft tasked with pulling off the feat has officially launched on its journey toward Mars
's largely unexplored moons, named Phobos and Deimos.If all goes to plan, the uncrewed vehicle will reach the moons of Earth's planetary neighbor next year, and even land on one before returning within five years.
The mission, which will rely on scientific instruments from NASA, the European Space Agency and others, aims to collect not only detailed observations of the moon, but physical samples from Phobos.
The results, scientists hope, might reveal not just the origin of the moons, but Mars itself at a time when NASA is working toward the first astronaut-led ventures to the planet.
Here's what to know about Japan's mission to Mars' two moons.
Japan launches mission to study Mars' moons, retrieve sample
The Japan Aerospace Exploration Agency (JAXA) launched an uncrewed spacecraft to Mars from the country's main spaceport, the Tanegashima Space Center. The launch took place early Tuesday, Oct. 20, local time from southwestern Japan.
The country's officials declared the launch a success after the Martian Moons eXploration (MMX) spacecraft separated from an H3 rocket's upper stage to continue on its journey to Phobos and Deimos.
What is Japan's Martian Moons eXploration (MMX) mission?
While Mars' rovers have snapped images of the planet's moons from afar, the mission marks the first time that Phobos and Deimos will be examined up close.
The MMX spacecraft is expected to arrive in Mars's neighborhood by August 2027. The vehicle won't just orbit near the moons, but will also land on Phobos – the larger and closer of the two – in December 2028 and collect a sample from the moon that could be returned to Earth by 2031, according to NASA.
Next stop: Phobos & Deimos 🌑
— ESA Science (@esascience) October 20, 2026
MMX has successfully launched from Tanegashima, Japan. Its mission is to observe Mars’s mysterious moons, collect a sample from Phobos's surface and return it to Earth.
👉 https://t.co/a1d9lyLM4i@JAXA_en @NASA @CNES DLR @ESA pic.twitter.com/yrte1lLIYv
Scientists suspect that the smaller asteroid-sized moons could either be the remnants of something that crashed into Mars, or themselves could be asteroids captured in the planet's gravity. The objective of the mission is to survey the two moons – including studying the elemental composition of Phobos surface – to determine their origin and evolution, according to NASA.
What to know about Phobos and Deimos
Translated as "fear" in Greek, Phobos is much closer to Mars than its brother Deimos, according to NASA. Orbiting Mars three times a day, Phobos is also the larger of the two moons.
Unlike Deimos ("dread," in Greek), which is drifting ever-outward and will eventually leave Mars' orbit, Phobos is on a collision course with the red planet. Because Mars' strong gravity is drawing Phobos about 6 feet closer to it every century, the moon is expected within the next 50 million years to either crash into Mars or break up into a planetary ring like Saturn's.
What was NASA's contribution to Mars mission?
NASA is among five of the world's space agencies that helped devise and launch the mission, which also relied on assistance from private companies like Blue Origin.
Specifically, NASA helped develop an instrument on the MMX spacecraft known as the MEGANE gamma-ray and neutron spectrometer, which will assist in sample collection on Phobos' surface.
NASA also funded scientists from the U.S. participating on the MMX science team, and will provide communications and navigation support from the agency’s array of giant radio network antennas on Earth known as the Deep Space Network.
Contributing: Reuters
Eric Lagatta is the Space Connect reporter for the USA TODAY Network. Reach him at elagatta@usatodayco.com
This article originally appeared on USA TODAY: Japan launches ambitious mission to grab a chunk of a Martian moon
