The search for life on Venus has a fascinating history. Carl Sagan famously and sarcastically said there were obviously dinosaurs there since a thick haze we couldn’t see through covered the surface. More recently, evidence has pointed to a more nuanced idea of how life might exist on our sister planet. A recent announcement of phosphine in the Venusian atmosphere caused quite a stir in the research community and numerous denials from other research groups. But science moves on, and now some of the researchers involved in the phosphine finding have come up with a series of small missions that will help settle the question more thoroughly – by directly sampling Venus’ atmosphere for the first time in almost 40 years.

Several interesting findings, and important questions, have cropped up in the absence of any current data. Venus is commonly depicted as a hellscape of sulfuric acid where any living thing would be instantly melted, either by the acid itself or by the extremely high temperatures and pressures present on the planet’s surface. But parts of its atmosphere have temperatures and pressures similar to Earth.  

That is not to say that life would thrive there as we traditionally know it. Those atmospheric parts are extraordinarily arid – about 50 times drier than the Atacama desert, the driest place on Earth. And they have an abundance of sulfuric acid, which most life has a hard time dealing with.

Graphic depicting the various zone of Venus’ atmosphere.
Credit – Seager et al.

Still, there have been intriguing findings from various sources that hint at the many unknowns of the Venusian atmosphere. Both Vega and Venera, two missions that sampled the atmosphere decades ago, found non-volatile chemicals that life needs to exist present in the cloud layer. Also, there is an unknown “UV absorber” in the atmosphere that somehow captures about 50% of the solar energy that is hitting the planet.

A novel type of particle could explain that UV absorption. Known as “Mode 3” in scientific circles, it was found in the lower reaches of the atmosphere. While not much is known about these particles, they were not spherical and not comprised of any liquid. Certain types of bacteria and organic compounds have the same absorption pattern found in the absorption of UV light. There is still a lot we have to learn about the processes of the Venusian atmosphere – primarily due to a lack of data.

With such limited data to go off, scientists have also turned to models to find if there was some pattern of life that could exist in the Venusian cloud layers. The answer was a resounding yes, with one of three options available for dealing with the incredible amount of sulfuric acid.  

UT video discussing the prospect of exploring Venus again.

A completely novel type of life could use sulfuric acid as a solvent, similar to how Earth-based life uses water. Alternatively, water-based life could protect itself with a protective shell. Some researchers were already able to encourage Earth-based life to develop a protective lipid layer that would insulate it from the sulfuric acid. Finally, life could have evolved to emit a neutralizing compound such as NH3 to eliminate the local effects of the sulfuric acid around it.

All these theories are fascinating, and all would be disprovable with more data on the atmosphere, which is where the Venus Life Finder (VLF) mission comes in. Rapid advancements in satellite technology have enabled the development of CubeSats – relatively inexpensive, easy to build (and reproduce) incredibly light satellites, and therefore easy to launch into space. Though their payload capacity is limited, they can hold one, or sometimes two, instruments to study a specific phenomenon. Since they are so inexpensive, it is possible to launch multiple missions with different instrumentation and mission objectives.

Graphic showing the orbit of the orbit and prove for the VLF mission.
Credit – Seager et al.

That is the path this new mission is going. Even more intriguingly, it is not sponsored by any state-funded space agency but by the Breakthrough Initiatives program, a non-profit research organization founded by billionaire Yuri Milner.  

The first of these missions would launch a 50 lb probe with a laser 38 million miles to ride through Venus’ atmosphere for three minutes. During those three minutes, it will use an instrument called an autofluorescing
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