Transport of impact ejecta from Mars to its moons as a means to reveal Martian history

TL;DR

This study investigates how impact ejecta from Mars reaches its moons, Phobos and Deimos, revealing that samples from these moons could provide diverse, time-resolved insights into Martian geological history.

Contribution

The paper introduces a novel numerical approach to analyze impact ejecta transfer from Mars to its moons, highlighting the potential for diverse geological samples to inform Martian history.

Findings

Ejecta from Mars to its moons are chemically and physically distinct from Martian meteorites.

Ejecta covers all Martian geological eras and includes various rock types.

Sample-return missions from Martian moons could reveal comprehensive Martian surface evolution.

Abstract

Throughout the history of the solar system, Mars has experienced continuous asteroidal impacts. These impacts have produced impact-generated Mars ejecta, and a fraction of this debris is delivered to Earth as Martian meteorites. Another fraction of the ejecta is delivered to the moons of Mars, Phobos and Deimos. Here, we studied the amount and condition of recent delivery of impact ejecta from Mars to its moons. Using state-of-the-art numerical approaches, we report, for the first time, that materials delivered from Mars to its moons are physically and chemically different from the Martian meteorites, which are all igneous rocks with a limited range of ages. We show that Mars ejecta mixed in the regolith of its moons potentially covers all its geological eras and consists of all types of rocks, from sedimentary to igneous. A Martian moons sample-return mission will bring such materials back to Earth, and the samples will provide a wealth of "time-resolved" geochemical information about the evolution of Martian surface environments.