Imaging of Titan from the Cassini spacecraft

Abstract

Titan, the largest moon of Saturn, is the only satellite in the Solar System with a substantial atmosphere. The atmosphere is poorly understood and obscures the surface, leading to intense speculation about Titan's nature. Here we present observations of Titan from the imaging science experiment onboard the Cassini spacecraft that address some of these issues. The images reveal intricate surface albedo features that suggest aeolian, tectonic and fluvial processes; they also show a few circular features that could be impact structures. These observations imply that substantial surface modification has occurred over Titan's history. We have not directly detected liquids on the surface to date. Convective clouds are found to be common near the south pole, and the motion of mid-latitude clouds consistently indicates eastward winds, from which we infer that the troposphere is rotating faster than the surface. A detached haze at an altitude of 500 km is 150-200 km higher than that observed by Voyager, and more tenuous haze layers are also resolved.

Ground-based radar observations of Titan: 2000–2008

“…In addition, specular reflection of sunlight from a liquid surface has been seen from a high northern latitude area (Stephan et al, 2010), however a wider search including lower latitudes have not detected any such glints (Porco et al, 2005). A smooth surface saturated by liquid hydrocarbons but with no standing liquid may be a possible explanation for this discrepancy.…”

AVIATR—Aerial Vehicle for In-situ and Airborne Titan Reconnaissance

“…Titan's cloud menagerie is most diverse over the poles. During southern summer frequent, large conglomerations of convective storms were present [20,113,122,123]. With the onset of southern autumn these have petered out.…”

“…[81]) or subsurface flow (e.g. [51]) following rainstorms [45,113]. Surface moisture at the Huygens landing site [111] also evidences an active methane-based hydrological cycle.…”

“…Titan surface illumination at wavelengths of ∼1 μm is ample. Cassini's ISS was able to see Titan's surface at 0.938 μm [113] despite having to look through an estimated 3.5 normal optical depths of haze scattering (extrapolated from Fig. 29).…”

The Near-Saturn Magnetic Field Environment

“…The most visited satellites are the atmospherically-rich Titan [Porco et al, 2005] and the geologically-active Enceladus [Dougherty et al, 2005]. In addition to the prime mission which lasted 4 years after SOI, the mission has been extended twice through equinox and solstice and is now due to end in September 2017.…”