Will solar system colonization be feasible/worth the cost in the foreseeable future?

Great Debates
141

The structure isn’t allowed to just form into a natural shape (which wouldn’t just be an oblate spheroid; without constraint the material would all migrate to the middle where centrifugal acceleration is highest to form a ring) but is constrained by the outer reinforcing overwrap, which keeps the outer surface of the shell under compression. The resulting acceleration from the initial slow rate of rotation is just enough to get the ice-silicate slurry to “stick” to the surface evently but not enough to cause it to migrate inward, and the spin rate is increased only when there is sufficient thickness to accept compression along the long axis tangent direction. The resulting shape is something like a truncated catenary, in which internal compressive forces balance the tension from rotation, which helps stiffen the structure (which is part of the reason we don’t want to make it too long or thin). Because the base of the seabed will always have a mild slope near the ends, it will probably need some kind of internal reefs to keep material from migrating, though you want a certain amount of material to be able to migrate in order to provide replacement (as material is ablated or sublimated from the outside, the material in the seabed will slowly freeze and become part of the shell) or allow for expansion of the structure, so an acute helical reef system to control the flow of material from the ends to the middle is probably desirable.

Note that the structure is not assumed to be free of maintenance or not requiring outside resources; while it should be robust and self-repairing against normal damage or punctures, in the long term it requires active maintenance and an occasional influx of raw materials (water, silicates, et cetera). However, it also allows for ready expansion and transformation, which is much more difficult to do with a manufactured structure such as a Stanford torus.

Stranger

142

I need to correct and expand on the previous post: the overwrap applies a radial compressive load (which opposes the outward pressure of the internal “sea”) pulling the outer surface inward and shifting the neutral ‘plane’ of the shell outward, but in the tangent directions (both about the spin axis and cross axis) the outer surface is still in tension, albeit substantially less than a purely tensile-supported spinning structure. So, the loading condition is somewhat critical in that the stress in the outer shell has to be low enough that it doesn’t constantly flow (which the short fibers help resist) but high enough that the structure is self-repairing against puncture or evaporation. The larger the structure is (and the greater the corresponding wall thickness) the less sensitive it is to variations in thickness and loading, and the more robust against damage, up to the point at which tensile stress exceeds limits of the overwrap or the compressive pressures are too great for the ice-silicate composite to remain solid.

Stranger

143

Reading this made me think of the really important need for artificial gravity, but once we get that, faster than light, and terra-forming technology, space colonization becomes much more feasible as instead of being stations, we can just live on the planet. I expect this not to come about until a 100 years maybe more. But the first “colonization” of space with without a doubt be in earth’s orbit.

144

I’m 55. I seriously doubt I’ll see anything other than very small parties living in space, in my lifetime; the most likely being asteroid mining of some sort.

Long term, though, as difficult to imagine it being (in reality vs. sci fi), interstellar colonization will be the only solution to what I suspect would otherwise be a relatively short lifespan for the human race. I think it’s far more likely we’ll destroy ourselves if we don’t decentralize.

Once we decentralize, the vastness of interstellar space, and more importantly, the vast time spans between colonies, will avoid most sources of conflict between colonies. If there are enough, then they won’t all go ballistic at close enough to the same time, and humanity just might last a long time.

145

I’m (almost) 51. I don’t expect to even see that.

More visitors to the ISS is the only other human space exploration I can see in my future. China may send men to the moon, just because, but that’s it.

146

I’m hoping that by the time we decentralize we won’t be human as-we-know-it any more.

In a century or two we may understand the human genome to the point where we can remove impulses that were useful in our evolutionary past but simply threaten our very survival now, and know full well all the implications.

This may seem a scary future to some, but it’s less scary to me than keeping our “stone age” minds forever.

147

I’d recommend keeping at least a few ‘stone-age minds’ around, just because they have been successful at surviving for over a hundred thousand years. Any new minds we create might be less well adapted to long term survival.

148

That’s scary to me, because bacon and ice cream just won’t taste as good! :-o

149

Apologies for the hijack.

Well I wasn’t suggesting binning the existing organ and starting from scratch.

Our minds, as they are, are increasingly poorly-adapted to the world we’re in. We still think tribally, and in a short-term way.
This is what makes most of the modern day problems humanity faces possible, as well as the possibility of nuclear armageddon.

If we understand brains well enough to manipulate them, we would probably be able to make our experiences more enjoyable and more vivid.

I’m certainly not of the “Vulcan” position that making humans better means removing all emotion, instinct, craving sensations etc. Because, in that scenario, what ever motivates us to do anything? Why would building a starship be better than lying in a ditch until we starve to death?

150

Why build colonies in orbit when you can build them on the moon? In orbit, all your mass has to come up from gravity wells. You have to rotate your colony to get gravity, which dramatically raises the mass requirements. The moon has gravity, and it has water. Lots of it. It has regolith which can be used as an engineering material. And, it may have giant habitats - lava tubes.

The Lunar Rilles you can see from Earth are collapsed lava tubes. It is almost certain that there are many such tubes which have not collapsed. These tubes are underground, protected from cosmic rays and micrometeorites, they are stable since there is no longer any lunar seismological activity, and they may be huge.

Here’s a picture of a lava tube on earth. These things can be miles long and 50 ft wide - on Earth. On the moon, where the gravity is lower and seismic activity nonexistent, there could be gigantic ones - an order of magnitude greater. As in, many kilometers long, and perhaps hundreds of meters wide. A single lava tube could house thousands of people.

Imagine coming up with an engineering method for sealing the walls of these tubes, and closing the entrances with air locks. Mine water, create oxygen, extract nitrogen from the regolith, and pressurize it. Thermonuclear power generation can provide heat and light, although like on earth, deep underground lava tubes are expected to have relatively mild, stable temperatures. And since lava tubes come in all sizes, we can start small and prove out techniques in tubes dozens of meters long and a few meters in diameter, then move to larger ones as we figure out how to do it.

Here’s a picture of a probable lava tube entrance on the moon. That thing is 427 feet in diameter. It’s possibly a ready-made space habitat.

There are already scientific uses for the moon. Radio astronomy and large optical astronomy could be done from there, among other things. But mostly it would be an excellent environment to prove out airless engineering techniques and perhaps be a way to provide mass to orbiting stations. Water shipped from the moon to something like ISS might be a lot cheaper than water shipped from Earth. If asteroid mining ever does get underway, the moon might be an excellent place to collect the material and process it.

In many ways, the moon is perhaps the most hospitable place for humans in the solar system other than Earth. Mars’s atmosphere will mainly drive dust into everything and act as a conductor of heat. Planet-wide sandstorms would not be fun. The atmosphere is so thin and the temperature so cold that you’re going to be wearing a space suit anyway, so what’s the point of going that far to build a colony when we have a nice stable airless world in our back yard?

Mars will one day be explored scientifically - there is plenty of science waiting to be done there. But it’s going to be the Antarctica of the spacefaring future - a distant place where a handful of people may be at any given time, and always for a tightly defined and short-term purpose. As Elton John said, Mars ain’t the kind of place to raise your kids. In fact, it’s cold as hell.

I could see the moon being a place for tourism, engineering, mining, and research. I don’t think we’ll ‘colonize’ it, but we could support large installations there to the tune of hundreds or thousands of people.

As for NASA, I think it’s a 20th century institution whose time has passed in terms of large ambitious manned space programs. Companies like SpaceX are rapidly developing capabilities that outstrip what NASA can do.

SpaceX’s Falcon Heavy will be the largest rocket to fly since the Saturn 5, and it will put mass into orbit for 1/6 the price of NASA’s best attempts. SpaceX is already working on an even larger generation of heavy lifters, rockets that can fly their booster stages back to the launching pad and soft-land them, and advanced space manoevering. Their ‘escape system’ is capable of being used for landing on other bodies and stays with the spacecraft instead of being jettisoned. The redundancy and safety they’ve built into their launch vehicles is very cool. They already have orbital capability and can dock with ISS, and their Dragon capsule will be man-rated shortly and has already flown a simulated manned mission into orbit and returned safely.

And SpaceX isn’t the only game in town. Bigelow Aerospace has already flown two inflatable habitats into orbit. They are currently testing a module that is 22 ft in diameter and 30 ft long inside - it dwarfs the individual modules of the ISS. They have plans to build their own station with these modules that will have as much interior volume as ISS.

There are already commercial applications being developed. A company called Planetary Resources plans to launch an array of small telescopes into orbit on which time can be rented by earth Astronomers. They want to use this to bootstrap a program of eventual asteroid mining. It’s easy to dismiss this as pie-in-the-sky until you look at the list of engineers and investors they have on board - they’ve assembled an A-team of engineering talent and financial capability.

If we are really going to move into space in a big way, it’s not going to happen through big government programs and centrally planned standalone missions. Instead, it’s going to emerge out of incremental improvements, economies of scale, and the creativity and competition of a large marketplace. Given enough demand for launchers, there will be robust markets in parts for launchers. There will be competition to drive down costs. There will be companies specializing in things like lunar lander systems or sub-components of rocket engines. In fact, there already are.

Space needs to develop like other markets have developed. Let the early adopters take the big risks and invest their fortunes. Some will fail spectacularly, but they will leave a trail of technological advancement behind them. Some will succeed, and when they start generating a profit it will attract more investment and more brains. New applications no one has thought of will be developed. New technologies will emerge out of the churn of the marketplace and open up still further applications, and the market will grow. Economies of scale will drive down the unit prices of specialized hardware.

We don’t know for sure if this will happen - markets are not predictable. It may turn out that demand is just too low and space access too expensive for any kind of rapid expansion of capital into that market. But it’s really our only hope. Governments have neither the money nor the will to do it - nor should they.

The market is already surprisingly large. Here is SpaceX’s manifest for upcoming flights - 40 launches before 2017. And only 7 of them are NASA contracts - all the rest are contracts to private companies. And Falcon heavy is supposed to fly next year. In 2015 SpaceX plans to launch its own manned orbital mission with its own astronauts.

Things are happening awfully quickly in the private spaceflight arena.

I see people betting that the Chinese will beat the U.S. to the moon, or to Mars. I don’t think so. If I had to bet on any single entity making it to Mars first, I’d bet on a joint venture between the likes of SpaceX, Bigelow and others, or their future equivalents. If it happens at all, it won’t be for decades. I may not live to see it.

The moon, however, is another question. I think we could see breakthroughs and engineering improvements that could make it feasible that a private moon mission launches within ten to fifteen years if the conditions are right.