Two weeks ago, NASA announced the selection of two new missions to explore the solar system. Psyche will fly to a metallic asteroid of the same name, and Lucy will explore “Trojan asteroids” that travel along Jupiter’s orbital path. The missions will advance our understanding of the origins of the solar system, and are by all accounts worthy missions. In choosing them, however, NASA passed on the chance to return to Venus, a planet in dire need of exploration.
A generation has now gone by since the agency set a course for the second planet from the Sun, and with this latest mission opportunity lost, the earliest an expedition there might launch (from some future selection process) would be 2027—nearly 40 years since our last visit.
For centuries, it would have been inconceivable that Venus would be in such a predicament. In the 18th century, Venus was the organizing force in international science. When humanity was finally able to stretch its arms toward the solar system, the first place it reached for was Venus. It was our first successful planetary encounter beyond Earth, and was the first planet on which humans crashed. It would later would host our first graceful landing.
Venus and Earth are practically twins. They’re alike in size, density, gravity, and physical makeup. They are both in our star’s habitable zone. Scientists have discovered no other adjacent planets in the entire galaxy that share such similarities. And yet somewhere along the way, Earth became a cosmic paradise for life as we know it, and Venus became a blistering hellscape. Beneath its sienna clouds of sulfuric acid is the greenhouse effect gone apocalyptic. At 850 degrees Fahrenheit, its surface is hotter than Mercury, though the planet itself is much farther from the Sun. A block of lead would melt on the surface of Venus the way a block of ice melts on Earth.