Japan has set off on an ambitious journey to Mars to bring back samples from one of the planet’s two small moons. However, getting there, landing on its surface and returning the samples to Earth will be anything but easy.
Launched on Monday aboard a 207-foot (63-meter) H3 rocket jointly developed by JAXA and Mitsubishi Heavy Industries, the Martian Moons eXploration (MMX) spacecraft will study the Red Planet’s two moons, Phobos and Deimos. It is expected to reach Mars in August 2027 before attempting two landings on Phobos to collect samples for analysis on Earth.
If successful, MMX will become the first mission to land on a Martian moon and return samples to Earth.
The mission comes nearly 15 years after Russia’s Phobos-Grunt (“Phobos-Soil”) mission, which failed to leave Earth orbit because of a spacecraft propulsion failure. The 14.5-ton spacecraft re-entered Earth’s atmosphere and crashed into the Pacific Ocean in January 2012.
Scientists believe the samples could provide clues to the early formation of the solar system and help resolve the long-standing debate over the origin of Mars’ two moons.
However, Phobos’ extremely weak gravity presents significant challenges that could complicate the mission. Landing on the moon and collecting samples will require precise maneuvers, while communication delays of up to 44 minutes for a round-trip signal between Earth and Mars mean the spacecraft must carry out critical operations with considerable autonomy.
Onwards journey to Martian moons
Upon reaching Mars, the spacecraft will enter a quasi-satellite orbit (QSO) around Phobos, allowing it to study the moon before attempting a landing.
The probe will spend about three years in the Martian system before beginning its return journey to Earth in November 2030. Much of these years will be spent studying the 14-mile-wide (22 km) Phobos with its science instruments.
Another mission under the space program involves deploying a Martian rover, IDEFIX, a joint mission between the French and German space agencies. The Japanese spacecraft is carrying the said rover, which is scheduled to be launched on Phobos’ surface in late 2028 or early 2029.
Phobos’ gravity is about 2,000 times weaker than Earth’s, making even the rover’s movements difficult. IDEFIX must travel slowly to avoid lifting off the surface, while the spacecraft will have just two to three hours during each landing to collect samples. JAXA aims to bring back at least 10 grams of material.
After careful mapping, the probe will select suitable landing sites and execute two separate touchdown events on Phobos to collect and stow samples in the spacecraft’s return capsule.
The probe is expected to perform a series of flybys around Deimos before departing for Earth in November 2030 and landing in Australia in 2031.
Moon samples to uncover origin mysteries
Scientists are depending on the mission’s success to unravel answers to long-held questions about how Mars got its moons.
One theory suggests Phobos and Deimos formed from debris produced by a massive impact involving Mars. Another suggests they were asteroids captured by the planet’s gravity.
Scientists would study the composition and mineralogy of the samples collected by the Japanese probe from the Martian moon, comparing them with the chemical fingerprints of Martian rocks and asteroid material. The analysis could help understand the origins of Phobos and Deimos.
Figuring out the moons‘ true origin story would provide key clues about Mars’ geological past, the solar system’s early history, and the formation of the inner planets, mission team members have said.