MMX Mission Will Study Phobos and Deimos

The MMX mission will characterize Mars’ two moons, Phobos and Deimos, investigate their origins, and deliver samples from Phobos to Earth. The spacecraft is targeted to launch from JAXA’s Tanegashima Space Center on Monday, October 19, at 3:41 p.m. EDT, or Tuesday, October 20, at 4:41 a.m. Japan time.

“Samples from MMX will bring paradigm-shifting science to the Mars system for generations to come, especially as NASA prepares to send the first humans to Mars,” said Nikki Fox, deputy administrator for the Science Mission Directorate at NASA Headquarters in Washington. “NASA and JAXA’s sample curation partnership is extremely valuable, and we are proud to share some of these samples for research as NASA Science supports MMX sample curation and continues to expand humanity’s understanding of the universe for the benefit of all.”

NASA’s Contributions to the Mars Moons Exploration Mission

NASA’s contributions to MMX include the Gamma-Ray and Neutron Mars and Lunar Exploration (MEGANE) spectrometer, a pneumatic sampler technology demonstration, and communications and navigation support through NASA’s Deep Space Network. NASA also funds U.S. participating scientists involved in the international mission.

NASA and JAXA are also collaborating on the curation and scientific study of the returned Phobos samples. The partnership will support research into the moon’s composition, origin, and relationship to the broader Martian system.

How MMX Could Solve the Mystery of Mars’ Moons

Scientists have long debated the origin of Phobos and Deimos. They could be remnants of a massive impact on Mars that sent material into orbit, or ancient asteroids captured by Mars’ gravity billions of years ago. Data and samples collected by MMX could help answer these questions and clarify the history of the solar system.

“Phobos and Deimos could be the remains of a massive impact on Mars that sent material into Earth orbit, or they could be ancient asteroids that were captured by Mars’ gravity billions of years ago,” said Tom Statler, MMX program executive and program scientist at NASA Headquarters. “Answering that will help us understand an earlier era when Earth and other inner planets may have acquired much of their water and organic compounds.”

MEGANE Will Analyze Phobos’ Chemical Composition

The MEGANE spectrometer—pronounced “mega-nai,” the Japanese word for glasses—will help scientists determine what Phobos is made of. The instrument will measure neutrons and gamma rays emitted by the moon’s surface to identify its chemical elemental composition, providing important clues about Phobos’ origin.

MEGANE was developed by the Johns Hopkins Applied Physics Laboratory.

NASA and JAXA Samplers Will Collect Phobos Material

NASA’s pneumatic sampler, known as the P-Sampler, is mounted on one of the spacecraft’s landing legs and is designed to collect surface material from Phobos.

The system complements JAXA’s C-Sampler, which uses a jet of high-pressure nitrogen gas to collect surface material and extract cores from several inches beneath the moon’s surface. NASA is expected to receive approximately 15% of the returned samples and will manage them at the agency’s Astro Materials Lab at Johnson Space Center in Houston, which has supported research for decades.

Blue Origin’s Honeybee Robotics developed the spacecraft’s pneumatic sampler mechanism.

When Will MMX Reach Mars?

The MMX spacecraft is expected to arrive at Mars in August 2027 and begin exploring Phobos and Deimos. After studying Phobos in detail, the spacecraft is expected to collect samples from the moon’s surface by December 2028 and return them to Earth in 2031.

International Science Partnership

NASA-backed researchers are working with international scientists to investigate Phobos’ history. They will use MMX mission data and the returned samples to search for new clues about the moon’s origin and the evolution of the Martian system.

NASA’s contribution to the MMX mission was developed under NASA’s Discovery Program. The program is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for NASA’s Science Mission Directorate in Washington.