A Balloon Mission That Could Explore Venus Indefinitely
Published on January 30, 2025 by Andy Tomaswick
Sometimes, the best innovative ideas come from synthesizing two previous ones. We’ve previously reported on the concept of having a balloon explore the atmosphere of Venus, and we have closely followed the progress of the Mars Oxygen ISRU Experiment (MOXIE) as part of the Perseverance rover on Mars. Combining these two ideas provides solutions to the challenges facing balloon exploration of Venus' upper atmosphere—recognized as one of the most habitable places in the solar system apart from Earth. This is the plan outlined by Dr. Michael Hecht, the principal investigator of the MOXIE system and a professor at MIT, along with his team for the Exploring Venus with Electrolysis (EVE) project. Recently, EVE was awarded Phase I funding from the NASA Institute for Advanced Concepts (NIAC) as part of their 2025 grant allocations.
Challenges of Current Balloon Missions to Venus
Current proposals for balloon missions to Venus encounter two significant challenges.
- Leaks in Buoyant Gases: The buoyant gases that keep the balloons afloat tend to leak over time, which limits the duration of missions.
- Dependence on Heavy Batteries: To endure Venus' 50-hour night cycle, these balloons must carry substantial battery supplies to power their electronics and systems necessary for maintaining internal temperatures.
Using the MOXIE System to Improve Viability
The EVE project aims to address these issues through a system similar to MOXIE, which famously produced oxygen on Mars by applying solid oxide electrolysis (SOE) to separate carbon dioxide into carbon monoxide and oxygen. While the MOXIE project has concluded, it has proven that producing oxygen is feasible in environments composed predominantly of carbon dioxide.
The Benefits of SOE in the Venusian Atmosphere
The upper atmosphere of Venus is rich in carbon dioxide, its primary atmospheric component. Both the oxygen and carbon monoxide produced through the SOE process are lighter than carbon dioxide, providing natural buoyancy that can keep the balloon afloat.
Moreover, Dr. Hecht notes another significant advantage of implementing the SOE system:
“When people ask me how MOXIE works, I always describe it as a fuel cell running backwards,” he explains. Additionally, during the night on Venus, “you could take a fraction, maybe 10%, of the carbon monoxide and oxygen that you made during the daytime and run it through the instrument backwards to generate power at night.”
This feature not only supplies an unlimited source of buoyant gases but also generates unlimited electricity—eliminating the need for heavy batteries. Additionally, carbon monoxide could be employed as a propellant for powered aircraft, which the balloon might support as a base station. The use-case scenarios for this innovative platform are vast.
Technological Developments for EVE
Conducting the SOE process in the Venusian atmosphere has distinct advantages. Due to the thickness of Venus's atmosphere, the SOE system requires only a fan, unlike the miniaturized compressive pump needed for the MOXIE system on Mars. Furthermore, Venus benefits from its proximity to the Sun, granting abundant solar power that can significantly aid system operations. In contrast, the Perseverance rover on Mars utilized a radioisotope thermal generator.
Concerns and Considerations
However, Venus presents unique challenges—for example, the presence of sulfuric acid in its atmosphere requires the EVE system components to be treated with protective coatings such as Teflon. Dr. Hecht remains unconcerned about weight limitations, humorously responding:
“How much mass is in your nonstick pan due to the Teflon coating?”
Efficiency and Design Balance
A delicate balance must be achieved within the SOE process. Dr. Hecht states that the design aims for a 75% conversion efficiency from CO2 to oxygen and CO. In cases where efficiency exceeds this target, excess CO can cause clogging as pure carbon (soot) accumulates in the apparatus:
| Target Efficiency | Resulting Output |
|---|---|
| 75% | Balanced output: equal buoyancy from oxygen and CO |
| >75% | Clogging due to excessive carbon buildup |
In summary, this presents a pragmatic solution to the longstanding challenge in the pursuit of Venus exploration. But the exploration ambitions do not end there. As Dr. Hecht mentioned, the SOE system could potentially be adapted for use on Titan and other planetary bodies with thick atmospheres.
The Future of EVE
As EVE progresses through the NIAC phases and the team initiates in-depth technical work, humanity edges closer to revolutionary technology aimed at exploring our nearest planetary neighbor.
Learn More
NASA / Michael Hecht - Exploring Venus with Electrolysis (EVE)
UT - Perseverance Successfully Extracts Oxygen From the Martian Atmosphere. About 10 Minutes of Breathing Time for an Astronaut
UT - A Balloon Mission that Could Try to Confirm Life On Venus
UT - The Best Way to Learn About Venus Could Be With a Fleet of Balloons
Lead Image:
Credit - NASA/Michael Hecht
