... Moon . ... Observing . ... Cassini tracks clouds developing over a Titan sea . ... NASA s Cassini spacecraft recently captured images of clouds moving across the northern hydrocarbon seas of Saturn s moon Titan. ... Cassini tracked the system of clouds developing and dissipating over the large methane sea known as Ligeia Mare for more than two days. ... But since a huge storm swept across the icy moon s low latitudes in late 2010, only a few small clouds have been observed anywhere on the icy moon. ...