About 65 percent of Saturn's moon Titan consists of uniform flat plains likely coated in up to a meter of fluffy organic material from its atmosphere. Researchers analyzing radar data from NASA's Cassini spacecraft propose a two-layer surface model. This finding could inform future missions to the hazy moon.
Saturn's largest moon, Titan, features vast expanses of strangely smooth terrain covering roughly 65 percent of its surface. A new analysis of radar observations from the Cassini spacecraft, which orbited Saturn from 2004 to 2017, reveals these plains are blanketed by a porous layer of organic particles that fell from Titan's thick, hazy atmosphere like snow, according to Alexander Hayes at Cornell University and his colleagues. The layer, potentially centimeters to a meter thick, overlays harder ground beneath and has been shaped by rain, wind, and erosion over time. Hayes noted that standard radar models used for bodies like Earth's moon or Venus fail on Titan. “Titan is a different beast in terms of the radar-scattering properties of the surface,” he said. The radar waves bounced in ways fitting a soft, low-density cover over solid terrain, with organics from the atmosphere compacting after deposition. This discovery aids understanding of Titan's dynamic weather and surface evolution. NASA's Dragonfly mission, set to launch in 2028 and arrive in 2034, will directly measure these layers, essential for designing future landers on the moon. The research appears in the Journal of Geophysical Research: Planets.