Analytical protocols for Phobos regolith samples returned by the Martian Moons eXploration (MMX) mission

Area of Science:

• Planetary Science
• Astrogeology
• Cosmochemistry

Background:

• Phobos, a moon of Mars, is hypothesized to be a captured asteroid.
• Its surface composition suggests primitive chondritic material, but its origin remains debated.
• Understanding Phobos is key to understanding the early solar system and Mars's evolution.

Purpose of the Study:

• To determine the origin of Phobos and the evolution of the Mars-moon system.
• To analyze returned Phobos samples for petrology, mineralogy, bulk chemistry, and isotopic compositions.
• To identify potential Martian material within the Phobos regolith.

Main Methods:

• Sample return mission by the Japan Aerospace Exploration Agency (JAXA) in 2024.
• Collection of >10 g of Phobos surface material from two different landing sites.
• Analysis of returned samples using techniques including stable isotope ratios (O, Cr, Ti, Zn), noble gas isotopes, organic matter analysis, and radionuclide chronometry (Mn-Cr, Rb-Sr).

Main Results:

• Geochemical and isotopic analyses will constrain Phobos's origin as a captured asteroid or other body.
• Noble gas isotopic compositions will reveal surface processes and solar wind interactions.
• Radionuclide dating will establish timelines for impacts, metamorphism, and aqueous alteration.
• Analysis protocols will be designed to detect and differentiate potential Martian materials.

Conclusions:

• The MMX mission and subsequent sample analysis will provide unprecedented insights into the origin of Phobos.
• The study will illuminate the history and evolution of the Mars-moon system.
• Detection of Martian material could offer unique perspectives on Mars's geological past.