NASA's DAVINCI mission is designed to answer long-standing questions about how Venus's atmosphere evolved and whether there remain chemical signatures of past oceans or even indicators of the role of water in shaping some of the highland regions on Venus, which make up about 8% of the planet's surface area.
DAVINCI will conduct special flyby remote-sensing observations designed to measure the chemistry and motions of the upper cloud deck, as well as mapping the regional-scale compositional differences between highlands known as tesserae (such as Alpha and Ovda Regio) and the dominant rolling plains that are believed to be basaltic like the lavas that erupt in Hawaii and Iceland.
DAVINCI also includes a 3.5-foot-diameter deep atmosphere probe, which is a flying chemistry/imaging/environment laboratory that will "take the plunge" into the Venusian atmosphere, and during its hour-long descent from the top of the clouds to the surface in a mountainous region bigger than Texas (Alpha Regio), it will make definitive measurements of noble gases, trace gases, the ratio of heavy to light hydrogen in water vapor and the role of sulfur in trace gases all the way to the foreboding near-surface, while measuring the environmental conditions every 15–50 m. These measurements will help us understand the current state of Venus, its possible past water, and how the planet formed and evolved.
DAVINCI will also conduct the first-ever descent imaging experiment using a near-infrared camera designed to distinguish rock types from beneath the clouds at scales as fine as ~10m while also measuring topography and landscape geomorphology. Many of DAVINCI's measurements have never been made in any planetary atmosphere before and these new data will inform scientists who build predictive models of how planets with big atmospheres change over time in response to volcanism, large-body impacts, and other effects (e.g., the loss of oceans).
DAVINCI is intended to fill in gaps that the science community has documented since the mid-1980s while paving the way for understanding how to compare exoplanets that appear to be Venus-like to the "real" Venus. Its measurements and outcomes will inform the history of Venus as a planet with a large atmosphere for decades, and permit other orbiter missions to conduct critical next-generation mapping of the planet's crust and shallow interior.