Torrence V. Johnson Biography

Voyager images show a bright, sparsely cratered Europan surface crossed by long fractures.

Voyager 1 images reveal Europa's bright, fractured icy surface.

Voyager 1 studies Titan's thick atmosphere during the Saturn encounter.

Voyager 1 data establish that Titan possesses a dense atmosphere dominated by nitrogen.

Voyager 1 measurements constrain Titan's atmospheric pressure and surface temperature despite its opaque haze.

Voyager 2 photographs bright wispy terrain across Dione's trailing hemisphere.

Voyager 2 images reveal the immense Ithaca Chasma canyon system crossing Tethys.

Voyager 2 images show Ariel crossed by valleys, faults and relatively young-looking terrain.

Voyager 2 photographs Oberon's heavily cratered terrain and prominent tectonic features.

Voyager 2 images reveal large fault valleys and impact structures across Titania.

Voyager 2 imagery confirms Umbriel's dark, heavily cratered surface and bright-ringed features.