Next Summer, NASA will pick two missions for its Discovery program out of the four that have been pre-selected. Among them, there is VERITAS, whose goal is to reveal the inner workings of Venus and perhaps explain why this rocky world is so different from Earth.

VERITAS stands for Venus Emissivity, Radio Science, InSAR, Topography & Spectroscopy. The spacecraft would study the surface of the planet, not an easy task when dense clouds cover its entirety. To combat this, VERITAS would be equipped with a radar system and infrared spectrometer.

"Venus is like this cosmic gift of an accident," said Suzanne Smrekar, principal investigator of VERITAS at NASA's Jet Propulsion Laboratory, in a statement. "You have these two planetary bodies – Earth and Venus – that started out nearly the same but have gone down two completely different evolutionary paths, but we don't know why."

A key aspect to investigate is the geological properties of Venus. Scientists want to know if the planet is still active, if it has volcanos, and if it is showing evidence of early-tectonic activity. Tectonics are crucial to Earth and possibly to the emergence of life on our planet. Venus could be an excellent model for the primordial Earth.

"Determining whether Venus is actively undergoing volcanic activity and understanding what process is driving it is one of the really exciting questions I'd love to see answered," said planetary scientist Jennifer Whitten, a VERITAS science team member at Tulane University in New Orleans.

The Venus mission is not just to be used as a comparison with our planet. Scientists are also discovering more Earth-sized planets beyond the solar system. While an Earth-twin is yet to be found, we have observed an exoplanet that might be Venus-like. Understanding our planetary neighbor could lead to a greater understanding of rocky exoplanets as a whole.

"To unwrap the mysteries of Venus we have to look under the hood at Venus' interior; it is the engine for global geologic and atmospheric evolution," said Smrekar. "Are Venus and Earth fundamentally unique worlds? Or are the differences between these 'twins' only cosmetic? Answering this question is key to understanding what makes other rocky planets habitable and, ultimately, emerge with life."

NASA will decide on the missions in Summer 2021. VERITAS' worthy competition includes another mission to Venus, one to study the volcanos of Jupiter’s Io, and TRIDENT, which will study Neptune’s moon Triton. If selected, VERITAS will fly in 2026.