While Mars may be all the rage right now, a team of NASA scientists has dreamed up an innovative concept that could eventually see humans permanently occupying Venus’ atmosphere, in a floating cloud city.

Everybody is keen to get humans to Mars; it’s been seen as the next logical step for some time now, mostly because of its Earth-like qualities. Our atmospheric chemistry is closest to Mars out of all the planets in the solar system, and its average temperature isn’t unreasonably cold (-63oC) either. Furthermore, both Earth and Mars have large polar caps that are believed to be predominantly composed of water ice.

But what about Venus, our closest neighbor? Venus is actually remarkably similar to Earth. So much so that it’s often described as Earth’s twin, albeit an evil or fiery one. The two planets are similar in size, mass, density, gravity and composition. So why aren’t we trying to get humans there instead? Well, it’s probably to do with the fact that it’s hellish.

It’s the hottest planet in the solar system, with surface temperatures reaching 465oC (870oF)—plenty hot enough to melt lead. It’s also shrouded in a very dense atmosphere with clouds of toxic sulphuric acid, and its crushing surface pressure is around 90 times that of ours.

So, Venus’ surface is pretty much a no-go zone. But what about taking up residence in its atmosphere? That’s NASA’s thinking anyway, and its Langley Research Center has already started to put forward some interesting ideas for a potential future mission, or five.

Named the High Altitude Venus Operational Concept (HAVOC), the evolutionary program comprises a series of ventures that would kick off by sending a robot into the atmosphere to test the waters, followed by a 30 day crewed, orbital mission. If successful, the next mission would be a crewed, 30-day venture in Venus’ atmosphere, ultimately leading up to humans spending a year in the atmosphere, or maybe even the establishment of a permanent presence in a floating “city.”

What sets this apart from other space missions is the crafts that NASA has dreamed up; helium-filled, solar-powered airships. As described by IEEE, the robotic version would be 31 meters long, whereas the crewed vehicle would be almost 130 meters in length. The top would be decorated with solar panels, a gondola would be built underneath for instruments and, in the manned vehicle, there would be a habitat for humans and an ascent robot that astronauts would use to both enter Venus’ orbit and return to Earth.

The ships would float 50 kilometers (31 miles) above the planet’s surface. Here, there would be only one atmosphere of pressure, and the temperature would be a reasonable 75oC. There would also be ample solar energy to power the crafts, much more than on Mars, and radiation exposure would be around the same as if you were in Canada.

This all sounds great on paper, but there are some serious hurdles that need to be overcome. They need to work out how to deploy the ships, which would have to unravel and fill themselves with gas. They also need to come up with a feasible way to safely get humans to the crafts, and home again. Much more thinking needs to be done, but it’s an exciting idea nonetheless.

[Via NASA, IEEE, Extreme Tech, Phys.org and io9]