Dust on Mars: What We Know, What We Don’t Know, and Why It Matters

Dust storms, which at their largest can blanket the entire planet for a month, were one of the earliest indicators of an atmosphere on Mars. Yet even today - over three centuries since their first telescopic detection, and more than half a century since we first observed one from orbit - we still can’t predict their occurrence and don’t fully understand how the largest storms begin, expand and decay. And that matters because of the huge impact lofted dust has on the thermal state of the thin martian atmosphere, which affects topics as diverse as surface winds and high-altitude water escape. Furthermore, layers of dust and water ice at the poles provide evidence of changes to the dust and water cycles over recent orbital epochs, while puzzling differences in dust lifting between landing sites led to an early end for the recent InSight mission when its solar panels became dust-coated. This talk will look at why dust is important to both Mars science and future mission planning; lay out what we do and don’t know about how the dust cycle works on Mars; and explain why a dedicated atmospheric and aeolian Mars surface mission is vital.