NASA is organizing a drone mission to Saturn's largest and icy moon Titan in search of life.
The Dragonfly mission will launch in 2026 and land in 2034.
Titan's atmosphere, made mostly of nitrogen, is believed to be similar to a very early-era Earth, scientists suggest.
It is the only other celestial body that was found to have liquid rivers, lakes and seas on its surface, though these contain hydrocarbons like methane and ethane, not water.
"Visiting this mysterious ocean world could revolutionize what we know about life in the universe," NASA administrator Jim Bridenstine said.
"This cutting-edge mission would have been unthinkable even just a few years ago, but we're now ready for Dragonfly's amazing flight,” he added.
"During its 2.7-year baseline mission, Dragonfly will explore diverse environments from organic dunes to the floor of an impact crater where liquid water and complex organic materials key to life once existed together for possibly tens of thousands of years," NASA said in a statement.
"Its instruments will study how far prebiotic chemistry may have progressed. They also will investigate the moon’s atmospheric and surface properties and its subsurface ocean and liquid reservoirs. Additionally, instruments will search for chemical evidence of past or extant life,” it added.