Similar Liquid Composition and Surface State of Titan's Northern Lakes From Cassini Bistatic Radar Experiment

During the T119 bistatic radar (BSR) experiment, the Cassini spacecraft observed a collection of lakes in Titan's Northern Lake District. Specular reflections from liquid surfaces were clearly detected at X-band ground-based station DSS-43 (Canberra), spaced out by sudden drops of power in correspondence to solid terrains. The forward scattering radar cross section suggests that all the observed lakes share similar composition and surface roughness. From the analysis of the reflected signals, all the lakes appear to be methane-dominated and potentially rippled by a few millimeters of aggregate surface roughness. A subsequent observation of the same district by Cassini RADAR in altimetry mode during T126 intersected the bistatic track over one of these lakes, revealing uniform backscattering across several basins. Lakes observed in bistatic configuration exhibit similar characteristics to those observed in altimetry mode, suggesting that all the liquid bodies present at Titan's lake district may have similar composition and roughness.