Balloon bots might help uncover Venus’ hazy secrets

Floating above the skies could be the trick to surviving and studying the planet's hellish landscape.
a silver balloon is inflating in a desert as the sun rises
A prototype aerial robotic balloon, or aerobot, is readied for a sunrise test flight at Black Rock Desert, Nevada, in July 2022, by team members from JPL and Near Space Corporation. This aerobot might one day venture to Venus. NASA/JPL-Caltech

After years of being bypassed in favor of exploring other far-distant locales in the solar system, Venus is on its way to experiencing a renewed wave of interest among researchers. 

A new mission concept out of NASA’s Jet Propulsion Laboratory could allow scientists to explore Venus like never before, all without ever touching the ground. Instead, it will soar high above the skies by balloon. While the NASA mission is still in its experimental stages, the concept involves pairing a small orbiter with an aerial robotic (or aerobot) balloon, about 40 feet in diameter. Though Venus has often been called Earth’s twin due to their similarities in size and structure, the two couldn’t be more different. Earth is a world teeming with life, while Venus is a primordial soup that might have burned away any chance it had of living organisms. Clearly they’re fraternal, not identical. 

Staying aloft in the upper levels of Venus’ atmosphere, the orbiter would use the planet’s powerful winds to circumnavigate the globe, all the while improving our knowledge of Earth’s sibling by taking scientific measurements of the planet. These experiments would range from analyzing the chemical compositions of its clouds, to monitoring the atmosphere for acoustic waves that could tell scientists more about Venus-quakes.  

A balloon might just be the key to traversing Venus’ challenging environment, says Paul Byrne, an associate professor at Washington University in St. Louis and a long-time science collaborator on the concept. “You really can’t get in other places as hospitable in the solar system as just above the cloud layer and Venus, which is pretty special,” he explains. 

[Related: These scientists spent decades pushing NASA to go back to Venus. Now they’re on a hot streak.]

Perpetually cloaked by a thick haze of carbon dioxide clouds, the second planet from the sun is home to some of the most scorching temperatures in our solar system. The planet is so hot, every spacecraft humanity has ever sent to its surface has essentially been melted down and crushed. To survive the hellish landscape, any spacecraft that plans to visit Venus (and live to tell the tale) would have to be made of materials able to withstand crushing air pressures—more similar to pressures a mile below sea level on Earth—and endure sulfuric acid rain. These falling droplets in the atmosphere are so highly concentrated, that they could easily burn a hole through a person’s skin. 

In floating miles overhead Venus’ surface, Byrne says that a balloon orbiter could potentially operate for several Earth months; a huge leap from other attempts to explore our closest neighbor. As the orbiter drifts across the Venusian sky, the craft will move higher as it is carried northward by the planet’s prevailing winds, “which means not only will we cover a huge amount of real estate, we will also be able to understand what the atmosphere is like at different times [of the] day,” says Byrne. Collecting data at different timestamps would be helpful in creating a more detailed picture of the planet’s atmosphere. Scientists might also be able to answer other mysterious characteristics of the planet, such as the lack of an intrinsic magnetic field

While using balloon-technology may seem like a novel alternative to conventional  spacecraft the US has deployed in the past, like landers and rovers, another space superpower used these buoyant devices to explore Venus decades earlier. In the 1980s, the Soviet’s unveiled the wildly successful Vega program, twin spacecraft that were designed to deliver payloads of advanced landers and balloons to the surface. The data Vega sent back allowed scientists to flesh out intricacies of the planet’s complex weather system. 

But now, more than 35 years later, the team at JPL and the Near Space Corporation recently completed two successful flight tests of a concept prototype in Nevada. The model is about one-third the size of what the craft would be if the idea is turned into a true mission. 

[Related: We finally know why Venus is absolutely radiant]

“The goal of this flight was to measure the flight dynamics of the balloon,” says Jacob Izraelevitz, a robotics technologist at JPL. One of the reasons they chose Nevada, Izraelevitz said, is because of its home to the biggest dry lake bed In the continental US. The vast, open landscape would make it easier to recover the craft and avoid any crashes into obstacles, like buildings or towers. 

The flights also revealed lots of practical information, the team noted. Based on the current estimate of the aerobot’s capabilities, they found that the balloon could carry about 100 kilograms of payload. This would be enough to pack solar panels, as well as communications technology needed for transmitting data back to Earth. And though the mission isn’t meant to be a life detection mission, learning more about the kinds of conditions that makes Venus uninhabitable may go a long way in understanding planetary environments that could support life. 

Caleb Turner, an aerospace project engineer at Near Space Corporation, says that the technology performed even better than expected. “These flight tests exposed the aerobot to its most extreme conditions yet, albeit nothing compared to the harsh Venus atmosphere, and it demonstrated a resilience that was beyond expectations,” he told Popular Science in an email. The aerobot was able to withstand balloon inflation, launch, flight to multiple altitude levels, and landing—important benchmarks that the prototype passed without a hitch. But Turner says they were able to do a second test merely a day later. The ease of repetition is a notable feat that “gives all involved a boost of confidence that this work is positioning itself to be ready for a Venus mission.”

Though it could be years before NASA sends this aerobot mission to the stars, the agency has already promised to head back to Venus with the upcoming VERITAS and Davinci+ missions, both slated for no earlier than 2028. As we continue to stretch past our own world to get a better view of others in the search for Earth-like planets, such a blistering destination is worth exploring again.