The best way to learn about Venus could be with a fleet of balloons

Interest in the exploration of Venus has exploded recently, especially after a disputed recent discovery of phosphine, a potential biosignature, in the planet’s atmosphere. Numerous missions to Venus have been proposed, and NASA and ESA have recently funded a number of them. However, they are mainly orbiters that try to look into the interior of the planet from above. But they are challenged by having to see through tens of kilometers of an atmosphere of sulfuric acid.

That same atmosphere is a challenge for ground missions. While some of the recently funded missions include a ground-based component, they miss an opportunity not offered on many other planets in the solar system: riding in the atmosphere. Technologists have proposed everything from simple balloons to entire floating cities – we’ve even heard of a plan to enclose all of Venus in a shell and live on the surface of that shell.

But for now, balloons seem like a simpler answer. That’s the mission modality proposed by a team of researchers at NASA’s Jet Propulsion Laboratory to discover more about something only confirmed to exist on Venus this past week: volcanism.

Scientists have long believed that there are active volcanoes on Venus. Some older probes collected data that indicated it, but it wasn’t until a recent study that analyzed data from Magellan that we knew volcanoes on Venus were still active. At this point, anyone can guess what that means for the study of seismology, evolution, and even the geophysiology of the planet. But the proposed JPL balloon mission could shed some light on it.

Their mission design, detailed in a paper published for free on one of the author’s personal websites, involves using a finely meshed network of balloons and an orbiting satellite to detect and track active volcanic events. travel and collect as much data as possible about it. That may sound difficult, especially without people being “in the loop” controlling where the balloons go, but it certainly beats letting them go wherever the wind takes them.

It’s much better — 63% better at achieving close-up observations of active or recently active volcanoes, according to the team’s simulations. But how they arrived at that number could use a little more explanation. First, how can you tell when a volcano is erupting on a planet completely shrouded in outside view?

They suggested using a technology called infrasound microbarometers — basically, these tiny tools detect pressure differences in the atmosphere caused by volcanic explosions. If you’re looking for a volcanic eruption, analyzing data from one of these instruments can at least point you in the direction of the pressure wave they create. Even pointing in the right direction, how can a balloon without its own active propulsion system get close enough to start collecting data?

According to the newspaper, they can simply ride on the wind. The atmosphere of Venus is complex and different layers can have different wind directions with different speeds. A balloon can raise or lower itself in the right wind current and thus drive in the direction of the eruption. Sounds pretty nifty, but one balloon alone wouldn’t necessarily be able to detect wind currents beyond its immediate vicinity, making it difficult, if not impossible, to plan a path to the volcano. That’s where the meshing comes in.

Orbiting above the planet and looking down through the atmosphere has one advantage: it allows the orbiter to see different wind currents that can be used to steer balloons in the right direction. In fact, if a balloon detects an interesting pressure change but can’t find a way there because of the local wind condition, the orbiter can relay that information directly to one of the other balloons in the group, which has a higher chance of getting there because of its own locale. wind patterns.

So it can act not only as a navigator for an individual balloon, but also as a relay and coordinator for an entire fleet.

Humans can still be useful, resulting in a longer time near potential points of interest if they were involved in the balloon system’s path. But humans also need to eat, sleep and do things other than watching distant robotic probes, so their response times can sometimes lead to a lag that prevents them from taking advantage of the current wind conditions. Therefore, an automated system around the planet could serve as the best and fastest way to find the way from the sensor to these spectacular events.

Once a balloon gets to one, they may even be able to drop a payload directly into the volcano’s caldera, gathering valuable information no matter how short the mission. Get enough chances for that, and the breakthrough of finding a single volcano on Venus will pass into scientific history as we begin to understand what made and propels our twin planet.