A new privately-funded mission will see scientists send a probe to explore Earth's neighboring planet, Venus, to see if it is home to life.
Dubbed the Venus Life Finder Missions, the series of projects is led by researchers from the Massachusetts Institute of Technology (MIT). Sponsored by the Breakthrough Foundation, its principal investigator behind is Jewish-American scientist Sara Seager.
“We hope this is the start of a new paradigm where you go cheaply, more often, and in a more focused way,” Seager said in a statement. “This is a newer, nimbler, faster way to do space science. It’s very MIT.”
Venus is one of Earth's closest neighbors. It's so similar in size that NASA has noted its nickname as "Earth's twin." However, its overall climate and atmosphere are radically different from ours.
The planet is mysterious, with NASA noting it as characterized by "a thick, toxic atmosphere filled with carbon dioxide – and it’s perpetually shrouded in thick, yellowish clouds of sulfuric acid that trap heat, causing a runaway greenhouse effect." The air pressure on the planet is intense, being 90 times greater than what can be experienced on the surface of the Earth - in fact, it is more comparable to the pressure found a mile under the ocean. It is also the hottest planet in the solar system, with surface temperatures estimated by NASA to be at about 475 degrees Celsius (900 degrees Fahrenheit), which can even melt lead.
Space agencies have sent probes to the planet in the past, being first scanned by a NASA probe in 1962 and later explored by others. Some of these continued recently, such as NASA's Parker Solar Probe, which has made multiple flybys of Venus in recent years. But landing missions are another story. Both the US and USSR attempted to land probes on the planet in the past, but they never lasted long, with a NASA probe landing in 1978 lasting just an hour in the intense conditions.
Despite this, many scientists see considerable value in the planet, and some even claim that microscopic life may exist in the atmosphere.
In September 2020, a team of scientists, including Seager, detected phosphine gases in Venus's clouds. This is not, in itself, a life form, as it is just a gas. However, phosphine is typically produced by anaerobic bacteria that live in oxygen-starved environments.
Many became excited at the time that it was evidence that life, albeit bacterial life, existed on another planet.
“The surface of Venus is uninhabitable, but the cloud deck – about 50 km above the surface – is similar enough to Earth’s lower atmosphere, and could theoretically support some microbial life,” Israeli-American astrophysicist Avi Loeb of Harvard University, a leading voice in the mainstream scientific community advocating for the search for extraterrestrial life, explained in February 2021.
However, there is still skepticism, as re-examining the data caused some to believe it was misinterpreted, and the molecules could actually be sulfur dioxide, which is common in Venus.
In order to find out, Loeb said, we would need to send a probe to collect samples from the cloud deck. This is not something that can be accomplished on an interstellar scale, but in the case of Venus, which is so close to Earth, it is very much feasible.
And this is what the Venus Life Finder Missions is going to do.
Their first mission is currently slated to launch in 2023 on an Electron rocket provided by the California-based Rocket Lab. This rocket will send a probe on a five-month trip for what will end up being just three minutes through the clouds.
But the probe will come equipped with a specially-designed laser instrument, with which it can detect complex chemistry inside the clouds. If any impurities or fluorescence are found, it could indicate that there's more to the Venusian atmosphere than meets the eye.
And there are already many mysteries about those clouds, anomalies regarding the chemicals and elements present and some particles of unknown composition.
If there is life on Venus, it is almost certainly microbial, as the clouds are essentially the only part of the planet even remotely potentially habitable, compared to the rest of the planet. And that's even after taking into account the many challenges still present on these clouds, such as the sheer concentration of sulfuric acid that dwarfs any concentration of sulfuric acid on Earth billions of times over.
But with these challenges, how could the clouds possibly host life?
According to Seager, there are a few ways. For example, these bacteria could produce ammonia to neutralize the sulfuric acid. But it is also entirely possible that life could exist in a way completely alien to us, with biochemistry that can tolerate sulfuric acid.
And this is something that other scientists have considered.
"What defines life? Nobody knows," noted Pete Worden, executive director of the Breakthrough Initiatives, a program founded by Russian-Israeli billionaire Yuri Milner that has helped fund Seager's research.
The findings of the 2023 mission could shed light on the many mysteries in the Venusian clouds. But regardless of its findings, a follow-up mission is already being declared for 2026. This time, a larger probe will be sent that could stay in the clouds for longer periods of time and gather more data. And all of that will lead up to the ultimate culmination of the entire project: Bringing back a sample of the Venus atmosphere.
“We think it’s disruptive,” Seager said. “And that’s the MIT style. We operate right on that line between mainstream and crazy.”