A UK-based mission is seeking to definitively determine whether life exists on Venus by sending a probe to the planet to search for microbial life in the Venusian clouds, rather than on the surface.

Over the past five years, scientists have identified phosphine and ammonia, two potential indicators of biological activity, in Venus’s clouds. On Earth, these gases are only produced through biological processes and industrial activities, and their origin on Venus remains unknown.

Given the planet’s dense, toxic atmosphere, extreme surface temperatures, and crushing surface pressure, the presence of a thriving industrial economy is highly unlikely. However, microbes, which can thrive in even the most extreme environments on Earth, may be able to survive on Venus and produce these gases, according to researchers.

“Our latest data has revealed additional evidence of ammonia on Venus, with the potential for it to exist in the habitable regions of the planet’s clouds,” said Jane Greaves, an astronomer at the University of Cardiff, in a statement. “There are no known chemical processes that can produce either ammonia or phosphine, so the only way to determine their source with certainty is to send a probe to the planet.”

This year, at the Royal Astronomical Society National Astronomy Meeting, researchers from the University of Cardiff presented their plan to search for and map phosphine, ammonia, and other hydrogen-rich gases that could indicate the presence of microbial life on Earth’s twin planet.

The mission, dubbed the Venus Explorer for Reduced Vapours in the Environment (VERVE), will launch a CubeSat-sized probe aboard the European Space Agency’s EnVision mission, a larger mission aimed at exploring Venus’s surface and interior, scheduled for launch in 2031. Once it arrives, the VERVE probe will detach and conduct an independent atmospheric survey.

In 2020, researchers first detected phosphine in Venus’s clouds, but the finding was met with controversy as follow-up studies failed to replicate the results.

However, a subsequent project, JCMT–Venus, which utilized the James Clerk Maxwell Telescope in Hawaii to study the molecular composition of Venus’s atmosphere, offered a possible explanation for these disparate findings. Researchers tracked the phosphine signature over time and discovered that it could only be detected at night, as it was destroyed by sunlight, and that the amount of gas in Venus’s atmosphere varied over time.

Last year, at the National Astronomy Meeting, researchers also reported the detection of ammonia in Venus’s atmosphere.

Although surface temperatures on Venus reach around 450 degrees Celsius, conditions become more reasonable approximately 31 miles above the surface, where temperatures range from 30 degrees Celsius to 70 degrees Celsius. Researchers believe that extremophiles, such as those found in Earth’s hydrothermal vents and deep-sea trenches, may be able to survive in these conditions.