Ancient Lake Bonneville's Salt Flats Become a Test Site for NASA's Venus Probe

Ancient Lake Bonneville, once nearly as large as Lake Michigan, spread across western Utah and parts of Nevada and Idaho during the Ice Age, according to NASA's Earth Observatory. It began forming about 55,000 years ago, when volcanic eruptions in what is now southeastern Idaho diverted the Bear River, sending water into Gem Valley and neighboring basins; a natural dam at Red Rock Pass held the lake back for tens of thousands of years.

About 18,000 years ago, that dam breached, releasing a flood that entered the Columbia River system and ranks among North America's largest -- over roughly six weeks, lake levels dropped more than 350 feet (105 meters). As the climate warmed and dried in the millennia that followed, the lake shrank into today's Great Salt Lake, Utah Lake and Sevier Lake, leaving behind flat playas and salt flats rich in evaporite minerals such as halite and gypsum, visible today as shoreline terraces in Landsat 8 satellite imagery.

In June 2026, NASA scientists and engineers working on the agency's DAVINCI mission to Venus visited Crater Island -- a site in the Bonneville basin they call "Venus on Earth" -- to field-test cameras and instruments that will eventually descend through Venus's thick atmosphere. During its 60-minute descent, the DAVINCI probe is designed to capture near-infrared images, measure atmospheric chemistry and study the Venusian environment in detail.

During the Crater Island rehearsals, the camera system, suspended from a helicopter, photographed hundreds of iron-rich and silica-rich rock formations as it descended toward the surface. Using only those images, the team built three-dimensional maps of the area that matched existing geologic maps, giving them confidence they can similarly map the geology of Alpha Regio, a mountainous region on Venus that DAVINCI will study.