Mining in Hell: The Problem of Venusian Metals

Post by Nic Quattromani:

In the space colonization crowd there are a few contrarian fellows who see the ever-popular Mars as a cold, irradiated waste of time, and look instead to the sunny real estate just two planets over on Venus. While steamy Venusian jungles and lizard men were long ago replaced by a scorching hot, acidic pressure cooker that ate Russian space probes for breakfast, there is some merit to the idea of putting your colony in the clement band of atmosphere some fifty kilometers above the surface, a wonderland where liquid water can exist, the ambient pressure is one bar, and Earth-normal air is a perfectly valid thing to fill a balloon with. Any colonist there could just hop outside in his oxygen mask, and from the balcony look out over kilometers upon kilometers of (deadly) sulfuric acid clouds. Compared to the hazards on Mars, with radiation, deadly cold, near-vacuum, and perchlorate soil added to the mix (but no acid, thank goodness), it really is a tempting prospect, and the Venus advocates have a strong business pitch. There’s only one (main) catch: how do you make a cloud civilization self-sufficient?

The problem, as I see it, comes down to materials. Energy requirements are a non-issue, since the planet is bathed in sunlight, and oxygen can be extracted (not necessarily easily) from atmospheric gases like carbon dioxide and carbon monoxide. With water (present as vapor, in modest amounts) you could even get some plants growing to make food and some building materials. A Venus colony could manufacture plastics, too, since all the elements are there, but I don’t know how easy that would be from a chemical perspective. Anything else would have to come either from imports, or from a trek down to the deadly surface fifty kilometers below. Supplying the planet’s industries with offworld machinery, metals, and electronics could be economical, given a well-developed asteroid belt infrastructure as well as a flexible definition of “economical,” but that is not self-sufficiency by any means, and in this post I’d like to explore the notion of a well-rounded Venusian civilization. To do that inevitably requires some way of extracting the mineral riches of the Solar System’s most hostile environment.

Now, this would not by any means be a task for humans, for space miners with their trusty space pickaxes. I shudder when I try to imagine what a Venus-rated EVA suit would look like. No, this is a perfect example of an environment suited to robots—and in this case they need not operate autonomously, not with a cloud city of Venusians floating overhead. I’m thinking that mining would involve several remote-controlled outposts scattered across the surface, each populated by robots which would extract minerals and ship them by elevator to a processing facility above the clouds. Most refinement of ores would probably be done by airborne industry, rather than surface plants, because machinery there would be vastly easier to operate, maintain, and protect from the environment. Only absolute essentials should be placed on the ground. Even electricity for rovers and rock-grinders might be delivered from above, via direct power lines or perhaps maser beams.

Probably the toughest challenge would be keeping electronics safe. The Soviet Venera 13 lasted just 127 minutes against the heat, and extra cooling systems will only prolong the time it takes  for a robot’s control systems to heat to the ambient temperature. Therefore a long-term Venus craft must operate at the ambient temperature. NASA has done some research into this (https://www.universetoday.com/137803/building-electronics-can-work-venus/), producing working silicon carbide semiconductors at the Glenn Research Center, and there have been other proposals for what amounts to a clockwork Venus rover, sidestepping the semiconductor problem entirely. To this list I’d like to add a hybrid method: keeping structural elements, motors, and basic electronics on the ground, while putting most computing power in a balloon kilometers up. Every motor and sensor would have its own radio link, with which to receive orders directly from the airborne control hub.

The mining robots will have to be extremely rugged in design, with multiple redundancies, few maintenance requirements, and, at least at first, simple components that can be manufactured in a frontier outpost. Sensors will be more delicate, perhaps requiring periodic replacement. Each robot in general might only have a few years of operation before it breaks down simply from heat stress and corrosion. The surface operation, then, would have to weigh metals extracted against metals re-invested back into new equipment. If the robots cannot extract enough material to both replace themselves and supply the colonies overhead, importing from the asteroid belt will be the only option. Exporting Venusian metals all the way to Earth and other planets will never be economical.

One major question I haven’t discussed yet is what metals can actually be found on Venus, and frankly I can’t find a lot of sources on it. The basaltic surface might provide silicon, iron, and other materials, though none of them will be concentrated. Venus does have some volcanoes as well as local tectonic activity, implying that geological processes may have concentrated some veins of ore, but other factors that concentrate metals here on Earth—plate tectonics and water—are absent. Also of note is the curious phenomenon of metallic snow. At high altitudes, Venus has snowcaps composed of lead sulfide and bismuth sulfide, which could be mined with relative ease (since we’re talking about soft substances above ground).

I imagine that the architecture of a Venus mine would be centered around a single hub, containing maintenance facilities, raw material stores, and an elevator to transport machinery in and minerals out. Buildings would be low, prosaic affairs, perhaps constructed from basalt slabs or bricks as well as metals. Basic roadways would connect them. It’d be a tidy, well-organized base, populated by machines rather than fallible humans, and broken equipment (there would be a lot of it, Venusian conditions being what they are) might be put in a graveyard, of sorts, off to the side, where it would await recycling for the next generation of mining robots.

Crawlers would sortie out from this depot to nearby mining zones. They’d have treads to negotiate often uneven terrain, modular frames to allow for easy replacement of components, and various drills and cutters equipped depending on the target (surface basalt, on most occasions, but I think there could be some tunneling in more volcanic areas). With the expansion of the mine the primary outpost would be supplemented by a ring of secondaries and support facilities. Habitats on the Venusian surface will never be viable before terraforming begins, far into the future, but until then there may yet be room for industrial development there.

Mining Venus will be expensive and technically demanding, there is no doubt about that. But I believe it can be done. With access to metals, then, a cloud civilization will have few barriers to its growth, as it can produce organics from the atmosphere and machinery from the surface. Can you imagine it? Fleets of solar-powered cloud cities soaring above the nearest planet, airships plying the skies between them, millions of people residing in pockets of breathable air filled with trees, glimmering buildings, and all the products of material abundance… that world does not have to remain a hellhole, not if we apply some good old human ingenuity. I’ll still defend Mars missions as much as the next space nerd, but the more I think about it, the better Venus is starting to sound.

What do you folks think? If anyone wants to start another round of the Mars versus Venus fight, the comments below are a perfect place to do it.

Sources:

https://www.universetoday.com/137803/building-electronics-can-work-venus/

https://en.wikipedia.org/wiki/Venus

Click to access 20030022668.pdf

https://en.wikipedia.org/wiki/Venus_snow

Images are public domain.