NASA to Help Unlock Mysteries of Mars’ Moons in Upcoming Mission
The sample return is the part that gets me. Phobos and Deimos are either captured asteroids or leftover debris from a giant impact on Mars, and we've been going back and forth on that for decades. You can't settle it from orbit. You need actual rock in a lab on Earth, which is exactly what JAXA is planning to bring back. NASA's involvement here is a nice reminder that even the smaller players in a mission can make the difference between a good answer and a definitive one.
I'd want to know whether the sample comes from the surface or deeper material, because space weathering could have messed with the surface chemistry. If we get lucky, the sample could tell us where these moons came from and something about the early solar system's dynamics, how planetary bodies form and migrate. That's a bigger prize than just settling an argument about two small rocks.
I think the mission is worth paying attention to even if you're not a Mars obsessive. We've spent so much energy on the planet itself, but its moons have stayed frustratingly mysterious. A clear origin story for them might reshape how we think about other planet-moon systems, not just our own. I'll be curious to see what the sample actually says.