Cloud cities. On Venus. No, this is not the pitch for a potentially awesome science fiction story — this is a real-life proposal currently being considered by NASA.
Though Venus’s surface is far too volatile for us to visit anytime soon, scientists believe there’s a “sweet spot” in the Venusian atmosphere that would be the perfect place to fly some exploratory air ships and eventually establish a legit cloud city. Even better? They think it could be a whole lot easier than going to Mars. Well, kinda.
At approximately 31 miles above the planet’s surface, you’ll find one atmosphere of pressure and gravity just a tad lower than that of Earth. The average temperature, though admittedly hot, is just 17 degrees (Celsius) above the average Earth temperature. Hot, sure, but not unmanageable. Compare that to the wasteland of Mars, and it doesn't sound too bad. Plus, since Venus is closer to the sun than Earth, that height is the perfect spot to tap into solar power — which could keep the ships (and cities?) running forever.
The Space Mission Analysis Branch of NASA's Systems Analysis and Concepts Directorate at Langley Research Center is working on a proposal to send a robotic probe followed by manned air ships to the planet, leading to a permanent settlement. The five phases would include robotic exploration, a crewed mission to orbit on a 30-day mission, a crewed mission to the atmosphere on a 30-day mission, a crewed mission to the atmosphere for one year and finally a permanent human presence.
So, why might this be easier (in some ways) than a mission to Mars? The distance involved. A round-trip jaunt to Venus (440 days) would take almost half the travel time as a mission to Mars (650-900 days). But that doesn’t mean every aspect is easier. As IEEE Spectrum’s Evan Ackerman noted in a report that quotes NASA scientist Dale Arney, putting all the pieces together in motion above an alien planet wouldn’t be for the faint of heart:
The crewed mission would involve a Venus orbit rendezvous, where the airship itself (folded up inside a spacecraft) would be sent to Venus ahead of time. Humans would follow in a transit vehicle (based on NASA's Deep Space Habitat), linking up with the airship in Venus orbit.
Since there's no surface to land on, the "landing" would be extreme, to say the least. "Traditionally, say if you're going to Mars, you talk about 'entry, descent, and landing,' or EDL," explains Arney. "Obviously, in our case, 'landing' would represent a significant failure of the mission, so instead we have 'entry, descent, and inflation,' or EDI." The airship would enter the Venusian atmosphere inside an aeroshell at 7,200 meters per second. Over the next seven minutes, the aeroshell would decelerate to 450 m/s, and it would deploy a parachute to slow itself down further. At this point, things get crazy. The aeroshell would drop away, and the airship would begin to unfurl and inflate itself, while still dropping through the atmosphere at 100 m/s. As the airship got larger, its lift and drag would both increase to the point where the parachute became redundant. The parachute would be jettisoned, the airship would fully inflate, and (if everything had gone as it's supposed to), it would gently float to a stop at 50 km above Venus's surface.
Considering the whole world is focused on Mars these days, even the team behind the proposal notes it's unlikely for the focus to shift anytime soon. But the project is still a fascinating pitch. Seriously, can you even imagine a real-life Cloud City? Lando would be proud.