He uses spacecraft-based remote sensing to study the properties of planetary surfaces, their interactions with the interior, and if present, atmosphere. Recently, he has focused on studying the coupling of surface, subsurface, and atmospheric processes on Titan and Mars. Hayes uses the Cassini RADAR to study and model surface morphologies on icy satellites, including the distribution and evolution of Titan's hydrocarbon lakes and seas. Using data from the Mars Exploration Rovers and Mars Reconnaissance Orbiter, he is also interested studying the depositional and diagenetic history of early Mars.