NASA administrator Jim Bridenstine described the planet Venus as “one stop in our search for life.”

“Today, we are on the cusp of amazing discoveries that could tell us more about the possibility of life off the Earth,” he said, in a statement. Astrobiology, which includes the search for life elsewhere, is a key priority at NASA, Bridenstine explained.

Bridenstine cited new research from an international team of astronomers that revealed the discovery of a rare molecule, phosphine, in the clouds of Venus.

The scientists noted that, on Earth, the gas is only made industrially or by microbes that thrive in oxygen-free environments.

The research, led by Professor Jane Greaves of Cardiff University in the UK, was announced by the Royal Astronomical Society and published in the journal Nature Astronomy.

Bridenstine described the discovery as “intriguing,” noting that it could point toward biosignatures. “As is normal in science, the more we learn, the more questions we have,” he said. “This is the virtuous cycle of discovery, including the discovery of potential biosignatures on other worlds.”

The NASA chief explained that four missions are being considered for up to two Discovery missions that will be selected in 2021. “Among them are an astrobiology mission to Neptune’s moon Triton and a geological mission to the most volcanically active planetary body in the solar system, Jupiter’s moon Io,” he said. “The other two missions being considered have proposed missions to Venus. One is focused on understanding its atmosphere and the other is focused on understanding Venus’ geological history.”

NASA is also partnering with Europe on another proposed Venus mission called EnVision, according to Bridenstine.