NASA reveals two robotic missions to Venus

NASA announced plans on Wednesday to launch a pair of missions to Venus between 2028 and 2030 – its first in decades – to study the atmosphere and geologic features of Earth's so-called sister planet and better understand why the two emerged so differently.

The space agency's new administrator, Bill Nelson, announced two new robotic missions to the solar system's hottest planet, during his first major address to employees on Wednesday.

"These two sister missions both aim to understand how Venus became an inferno-like world capable of melting lead at the surface," Nelson said.

The US space agency said it was awarding about US$500 million each to develop the two missions, dubbed DAVINCI+ (short for Deep Atmosphere Venus Investigation of Noble Gases, Chemistry and Imaging) and VERITAS (an acronym for Venus Emissivity, Radio Science, InSAR, Topography and Spectroscopy).

DAVINCI+ will measure the composition of the dense, hothouse atmosphere of Venus to further understand how it evolved, while VERITAS will map the planet's surface from orbit to help determine its geologic history, NASA said.

DAVINCI+, consisting of a fly-by spacecraft and an atmospheric descent probe, is also expected to return the first high-resolution images of unique geological characteristics on Venus called "tesserae." Scientists believe those features may be comparable to Earth's continents and suggest that Venus has plate tectonics, according to NASA's announcement.

Earth's closest planetary cousin and the second planet from the sun, Venus is similar in structure but slightly smaller than Earth and much hotter. Above its forbidding landscape lies a thick, toxic atmosphere consisting primarily of carbon dioxide, with clouds of sulfuric acid droplets.

The consequence is a runaway greenhouse effect that scorches the surface of Venus at temperatures as high as 471 degrees Celsius. The "air" on Venus is so dense and pressurized that it behaves more like a fluid than a gas near the surface.