Japan launched the Martian Moons eXploration (MMX) mission on Monday, beginning a five-year expedition to retrieve samples from Phobos, the largest moon of Mars. The $578 million project aims to land on the irregularly shaped satellite and return at least 10 grams of material to Earth for analysis.
The spacecraft lifted off at 3:41 p.m. EDT from the Tanegashima Space Center in southern Japan. It rode atop an H3 rocket, Japan’s flagship launch vehicle, which utilized a new configuration with four strap-on solid rocket boosters and an extended payload shroud. The rocket accelerated the nearly 9,900-pound spacecraft to more than 24,000 mph, allowing it to break free of Earth’s gravity for the 10-month journey to the Red Planet.
MMX mission trajectory and landing plans
After separating from the rocket about 71 minutes after liftoff, the spacecraft deployed its solar panels and established contact with ground controllers. Mission officials reported the vehicle was in a stable condition shortly after separation.
Upon arriving at Mars next August, the MMX spacecraft will jettison its propulsion module to reduce mass. The main exploration module, equipped with four-legged landing gear, will then maneuver into a quasi-satellite orbit. This trajectory keeps the spacecraft bound to Mars while allowing it to hover near Phobos, as the moon’s gravity is too weak to support a stable independent orbit.
The mission’s primary objective involves landing on Phobos in late 2028 or early 2029. The spacecraft will attempt up to two landings, using its landing gear to absorb impact energy and prevent bouncing back into space due to the moon’s feeble gravity. A small rover named Idefix, contributed by French and German space agencies, will also be released to drive across the surface for up to 100 days.
During the landings, the probe will use two independent mechanisms to collect samples. A coring drill on a robotic arm will extract a cylindrical specimen, while a pneumatic sampler provided by NASA will fire high-pressure nitrogen gas to sweep surface debris into a collection canister.
Scientific goals and international collaboration
Scientists hope the MMX mission will determine whether Phobos and its smaller sibling, Deimos, are captured asteroids or remnants of a giant impact on Mars early in the Solar System’s history. Phobos resembles asteroids from the outer belt, but its proximity to Mars suggests it may also contain traces of the planet itself.
Japan’s space agency, JAXA, is leveraging its success with the Hayabusa and Hayabusa 2 asteroid sample return missions to lead this complex endeavor. The project includes contributions from NASA and European space agencies. NASA provided the pneumatic sampler and a gamma-ray and neutron spectrometer to measure the elemental makeup of the moons.
In return for its contributions, US researchers will receive 15 percent of the returned specimens. The samples will be recovered in South Australia in 2031 and transported to laboratories in Japan for detailed study.
Yoshihiro Seki, Japan’s science minister, stated that the mission aims to contribute to the development of the nation’s space science and exploration technology. Tom Statler, a lead scientist at NASA, noted that bringing samples back to Earth will allow researchers to determine if the material is consistent with asteroid composition or debris from a collision involving Mars.
The mission follows previous failed attempts by the Soviet Union and Russia to retrieve samples from Phobos. With the MMX mission, scientists expect to finally acquire ground truth data on the Martian moons, which could also inform future human exploration strategies for the region.
Source: Ars Technica
