A Japanese spacecraft rocketed toward Mars on Tuesday on an unprecedented quest to explore its mysterious moons and bring back samples.

Five of the world’s space agencies joined forces for the five-year mission that will attempt to land a robotic prospector plus a rover on Phobos, the larger and closer of Mars’ two pint-sized moons.

The Japan Aerospace Exploration Agency, which is leading the bold sampling effort, launched the spacecraft before dawn from the country's main spaceport on Tanegashima Island.

While NASA has successfully landed nine spacecraft on Mars over the past 50 years and China scored a 2021 touchdown, no one has ever ventured onto Phobos or its sidekick Deimos. And no one has managed to fetch samples from Mars, let alone its moons.

If successful, bits of dust, soil and rocks from Phobos will arrive on Earth in 2031.

“There’s a lot of adrenaline and a lot of excitement and a lot of wow,” said NASA astrophysicist Tom Statler, who’s involved with the project.

Japan has an edge going in, with two asteroid sample returns already under its cosmic belt.

Phobos is a lumpy, potato-shaped rock just 14 miles (22 kilometers) or so across. Examining pieces of it can explain how Mars’ moons — and possibly moons elsewhere — came to be.

Dubbed MMX for Martian Moons Exploration, the $578 million mission features a hefty 5-ton spacecraft that should reach Mars by late next summer. It will sync up with Phobos’ tight orbit around the red planet, before ejecting the French-German rover that’s named Idefix after the white terrier in the Asterix comics.

No bigger than a microwave oven, Idefix will plop onto Phobos by itself, bouncing for several minutes before coming to a halt in the moon's extraordinarily low gravity.

The four-wheeled rover is designed to right itself if it lands upside down. All bets are off, though, if it sinks into soft soil or gets wedged between rocks, said the French Space Agency’s Julien Baroukh. Once the rover’s solar panels are deployed, the vehicle can no longer right itself, he added, which is why it will move at a glacial 1 millimeter per second (0.04 inches per second).

Idefix will serve as a “scout for safety,” according to Baroukh, as it prowls around Phobos for 100 days. Japanese flight controllers want to avoid powdery soil and rough terrain when the mothership — a four-legged stationary lander — descends to the surface to gather samples in late 2028 or 2029.

The lander will spend just two hours on Phobos, drilling and vacuuming up at least one-third of an ounce (10 grams) of material, before launching back into space. It will study Deimos during a series of flybys before leaving the Martian neighborhood in 2030 and hustling back to Earth for a 2031 sample delivery in the Australian desert.

It’s a treacherous undertaking, with wreckage littering the path.

The moons’ names aren’t exactly comforting: Phobos is Greek for fear and Deimos means dread. They’re the twin sons of the god of war Ares — Mars in Roman mythology.

Russia stumbled in all three of its Phobos attempts as well as many other Mars endeavors. In its only other Mars mission, Japan failed to get a spacecraft into orbit around the red planet. Even NASA has had its share of flops in a bid to answer the burning question: Did life ever exist on Mars?

By studying Mars’ moons, scientists hope to learn whether Phobos and Deimos formed in the aftermath of an ancient collision between Mars and a battering space rock. It’s also possible that the moons might be stray asteroids that became ensnared in Mars’ gravity.

Either way, scientists anticipate finding traces of Mars on Phobos, making the samples an irresistible two-for-one that should help demystify planetary and moon formation, and perhaps even the recipe for life. The findings will help shape future Mars missions, including those by astronauts, said NASA’s acting planetary science director Lindsay Hays.

“It is a once-in-a-lifetime chance. We are part of the first sample return mission from the Martian system,” said the Germany Space Agency's rover chief Markus Grebenstein.

Japan isn’t the only one looking to claim the scientific riches packed into the Martian system’s rocks and dirt. China plans to launch a sample return mission to Mars in 2028, while NASA is still debating how to retrieve the more than 30 sample tubes collected by the Perseverance Mars rover, the new champion for off-Earth driving.

Japan and China could be neck-and-neck in getting samples back from the Martian system. Both are targeting 2031.

Japan is investing $350 million in this mission. NASA is contributing $87 million, the French Space Agency about $68 million, the German Space Agency about $56 million and the European Space Agency some $17 million.

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