The surface features and overall topology of Venus have been determined primarily by:

Question

Quizplus · Accepted Answer

Radar methods from Venus-orbiting spacecraft have been used to map the surface features and topology of Venus by measuring radio echoes from the surface. This technique has been used extensively to study the surface of Venus due to the thick clouds that obscure its surface from visible and UV light, making it difficult for photographic and lander missions. Balloon-borne spacecraft have been used to study the atmosphere of Venus but not the surface, and the Space Shuttle has not been used to study Venus.

The Surface Features and Overall Topology of Venus Have Been