Portal:Solar System/Did you know/15

• ... that troilite, a form of pyrrhotite, is extremely rare on Earth but is abundant on Mars (pictured)?

• ... that on the Mars Exploration Rover (artist's impression pictured), a technique known as visual odometry allowed the rover to estimate its position and orientation using only camera images?

• ... that ejecta from the impact that created Zunil crater in Athabasca Valles on Mars is a possible source of Martian meteorites?