IEEE Spectrum has an interesting article, NASA Study Proposes Airships, Cloud Cities for Venus Exploration. I love airships, so I love this idea.
The surface of Venus isn’t going to work for humans, but what if we ignore the surface and stick to the clouds? Dale Arney and Chris Jones, from the Space Mission Analysis Branch of NASA’s Systems Analysis and Concepts Directorate at Langley Research Center, in Virginia, have been exploring that idea. Perhaps humans could ride through the upper atmosphere of Venus in a solar-powered airship. Arney and Jones propose that it may make sense to go to Venus before we ever send humans to Mars.
To put NASA’s High Altitude Venus Operational Concept (HAVOC) mission in context, it helps to start thinking about exploring the atmosphere of Venus instead of exploring the surface. “The vast majority of people, when they hear the idea of going to Venus and exploring, think of the surface, where it’s hot enough to melt lead and the pressure is the same as if you were almost a mile underneath the ocean,” Jones says. “I think that not many people have gone and looked at the relatively much more hospitable atmosphere and how you might tackle operating there for a while.”
Winds around the equator of Venus would carry an airship around the planet in 110 hours.
At 50 kilometers above its surface, Venus offers one atmosphere of pressure and only slightly lower gravity than Earth. Mars, in comparison, has a “sea level” atmospheric pressure of less than a hundredth of Earth’s, and gravity just over a third Earth normal. The temperature at 50 km on Venus is around 75 °C, which is a mere 17 degrees hotter than the highest temperature recorded on Earth. It averages -63 °C on Mars, and while neither extreme would be pleasant for an unprotected human, both are manageable.
What’s more important, especially relative to Mars, is the amount of solar power available on Venus and the amount of protection that Venus has from radiation. The amount of radiation an astronaut would be exposed to in Venus’s atmosphere would be “about the same as if you were in Canada,” says Arney. On Mars, unshielded astronauts would be exposed to about 0.67 millisieverts per day, which is 40 times as much as on Earth, and they’d likely need to bury their habitats several meters beneath the surface to minimize exposure. As for solar power, proximity to the sun gets Venus 40 percent more than we get here on Earth, and 240 percent more than we’d see on Mars. Put all of these numbers together and as long as you don’t worry about having something under your feet, Jones points out, the upper atmosphere of Venus is “probably the most Earth-like environment that’s out there.”