Science & Logic of Settling Solar System

[Coyote]

In the midst of all the questions about athiesm and higher beings, etc... I prefer to ask about something that I've been pondering for some time now:

Let's propose that geo-political life on Earth continues on a fairly predictable course: nation states still continue to be the primary arbiters of life, liberty or lack thereof, of finances, secrets, and materiels. There will be wars but not the huge, continent or global scale wars like World War Two but mostly brushfire and regional conflicts, where things like Iraq are the biggest, loudest types.

Corporations will continue to hold influence and various NGOs will also make their prescence felt-- the UN, WTO, multi-national corps and so on continue to seek their goals. Nations across the world will continue to have their various leaders, ranging from exceptional and exemplary statesmen to stumbletyfuck misfits. In other words, major, catalcysmic socio-political upheaval is unlikely. USA, Europe, Asia, Russia, Middle East, etc-- they will continue to cycle up and down in their fortunes with only modest turns rather than revolutionary events. Wars will eventually end, to be replaced by others in time.

Now, we know that there is water on multiple bodies in the solar system-- Moon, Mars, Asteroids, various Moons of Jupiter and Saturn. Let's posit that we find a material or discovery, we'll call it "Discovery X", that is found to be fairly profitable, in the solar system. It is something that cannot be found or replicated on Earth.

"Discovery X" could be an industrial process, a cure, a mineral, even an energy or perhaps even a philosophical concept. It is not a earth-shattering breakthrough like nuclear fusion or cure for cancer-- no free lunches or universal band-aids. Just something really quite useful but modest in scope. It is just worth it to go out to the solar system and exploit it while facing the expected battery of hazards and costs-- like the earlies colonization of the New World.

How long would it realistically take for governments and/or corporations, working alone, or in concert, to realistically expand to fill the Solar System as we currently know it so that we have sizeable cities worthy of the name on the Moon and Mars; research bases on the Jovian Moons; orbital space stations where people actually live, work and play with their families long-term, and where inter-planet travel within the system is relatively commonplace and ordinary working-class people can realistically expect to buy a ticket for a vacation or honeymoon to such a place?

A hundred years? Fifty? Five hundred plus?

I'm not interested in a science-fiction thread, but hard science. No FTL travel, no wormholes, space warps, etc.

[GrandMasterTerwynn]

Now, we know that there is water on multiple bodies in the solar system-- Moon, Mars, Asteroids, various Moons of Jupiter and Saturn. Let's posit that we find a material or discovery, we'll call it "Discovery X", that is found to be fairly profitable, in the solar system. It is something that cannot be found or replicated on Earth.

"Discovery X" could be an industrial process, a cure, a mineral, even an energy or perhaps even a philosophical concept.

We already know what 'Discovery X' will likely be. We're requiring more and more increasingly rare metals to drive our technological machinery. Metals not commonly found on Earth, but likely to be found within asteroids. For that matter, more common metals are apt to become sufficiently rare that effort would go into developing them from asteroids.

The problem is one of cost. It costs something like 62 MJ/kilogram to get something into orbit, plus the energy cost to move it to your asteroid mine. This cost is applied to the trained labor, initial equipment and life-support. This can be quantified in terms of kilograms of rocket propellant or watts of electricity spent on a giant laser beam, or whatever.

Economically speaking, once the demand for this resource is sufficient to support sufficient sales volume to offset the costs (enough to deliver a profit to the company's shareholders) of setting up asteroid mines (including required technological development,) then asteroid mines will be built.

This is the same problem that will face the other likely "Discovery X," that likely being some manner of null-gravity manufacturing technique. You have to pay to send up the people, and bring back down the finished products. Provided a profit can be made, and the startup costs aren't likely to cause bankruptcy, then there will be a certain incentive for these space-based foundries to be built.

It is just worth it to go out to the solar system and exploit it while facing the expected battery of hazards and costs-- like the earlies colonization of the New World.

Once the initial costs come down enough that the investment can be recovered in reasonably profitable timescales, then it will be done. After all, colonies weren't founded out of the goodness of the hearts of the leaders of the colonial ventures. They went over expecting to create profitable ventures, and expected the costs of acquiring, crewing, and provisioning a ship to be recoverable by rum/spice/cotton/tobacco trade. The thing that will slow initial progress is the extremely steep startup costs.

How long would it realistically take for governments and/or corporations, working alone, or in concert, to realistically expand to fill the Solar System as we currently know it

It'll be a number between several centuries and never. Technology has only now advanced far enough that private companies are developing sub-orbital space-tourism, and are exploring ways of having permanent low-Earth orbit presences. Governments in concert are just now finally talking about permanent manned lunar presence, on a timetable of 2020 or beyond. A tentative manned Mars landing is, increasingly, looking like something we won't get to until half the century is gone. You might see some tentative steps out into the near-Earth asteroids, and increasingly firm steps towards Mars in the second half of the century, but nothing that could really be defined as a robust permanent human presence, at least one robust enough to withstand the trials and tribulations of Earthly politics.

This progress will be hampered by the need to address global warming, to address the impending end of the cheap energy era, global overcrowding, and the increasing scarcity of natural resources. Some of these problems will require solutions that might be contrary to developing a burgeoning space presence, and the solutions to some of the other problems, especially the one about dwindling supplies of metals, can only be addressed with a strong space presence.

It really is going to be something of a race between developing robust space-based capabilities, and being crippled (or at least severely hamstrung) by Earthly problems. Winning the race means survival, losing it (pessimistically speaking) will eventually condemn us to being permanently trapped on Earth.

so that we have sizeable cities worthy of the name on the Moon and Mars;

At least a couple of centuries. Likely more. Gravity wells are expensive to climb in and out of. The lion's share of space development will probably be aimed towards lunar development and the near-Earth asteroids.

research bases on the Jovian Moons;

We'll have unmanned long-term robotic research going on on the largest moons of Jupiter before the century is out. However, the most interesting moons are the most challenging to get to, since they sit smack-dab in the middle of Jupiter's Van Allen belts. A permanent manned presence on the Jovian or Saturnian moons will probably wait until well into the 2100s or 2200s, since Jupiter and Saturn are much further out and take much longer to get to.

orbital space stations where people actually live, work and play with their families long-term,

If Bigelowe and others have their way, this will probably become the case by the end of this century.

and where inter-planet travel within the system is relatively commonplace and ordinary working-class people can realistically expect to buy a ticket for a vacation or honeymoon to such a place?

Define "inter-planet," if you mean between Earth and Mars and the closer asteroids . . . this is achievable before 2500. If you mean "a honeymoon on Pluto, affordable to a working-class stiff," it'll probably a millenium at the earliest. Space habitats are simply not going to be able to support the kind of explosive growth that Earth has. Mars might, but terraforming it to that point will take centuries at least. This means that expansion through the solar system is going to be fairly slow. Especially since there's a lot of desirable real-estate to exploit inside the orbit of Jupiter.

A hundred years? Fifty? Five hundred plus?

Try a thousand years plus. Depending on who you talk to, this would be either exceedingly optimistic, or excessively pessimistic. I tend to think that it's on the pessimistic side of 'reasonable.'

[Sikon]

A good step in future prediction is to first look at the past.

Presumably almost anyone reading this already knows the basics, like Sputnik in 1957, the Apollo manned lunar landings in 1969-1972, etc.

Let's look at a sample of a few past plans:

1967: NASA LESA lunar base plan with extended manned lunar surface missions to begin in 1970, over the 1970s reaching a permanent base.

1968: IMIS Mars mission study by Boeing for NASA, estimating full-scale development starting in 1976 would lead to a Mars landing in 1985-1986

1989: President George H.W. Bush proposes a Space Exploration Initiative with a Moon base and manned mission to Mars, leading to a plan with manned lunar landings starting in 2003-2004.

2004: President George W. Bush proposes a Space Exploration Program with a Moon base and manned mission to Mars, leading to a plan with manned lunar landings starting in 2015-2020.

Look at the above carefully, and one can see a historical trend...

More past Moon base and past Mars mission plans are described here and here respectively.

As most people are aware, back in the 1940s and 1950s, science-fiction predictions of the future commonly envisioned large-scale spaceflight by the year 2000, with huge spacestations, large moonbases, etc. Why didn't that happen? The following is a good illustration:

For the 1952 Von Braun Mars Expedition, imagining 37000 tons of spacecraft, Von Braun noted "the 5,320,000 tonnes of rocket propellant required for the entire enterprise* was only 10% of the amount delivered in the Berlin Airlift and would cost only 4 million dollars."

* (Fuel was primarily for launch from earth, assuming 297 sec vacuum-Isp and 69:1 T/W ratio engines, less than later obtained in real life).

Of course, nobody would expect total costs to be only the fuel costs of $4 million in 1948 to 1952 dollars, equivalent to $30 million or $0.03 billion in today's dollars, but it is worth noting just how much costs went up due to launch vehicles actually costing so many orders of magnitude above fuel costs.

The difference later on is illustrated by an October 1989 NASA Mars study in which the cost of a Mars mission was estimated as $258 billion in 1989 dollars, equivalent to $420 billion in today's dollars. Such involved 1300 tons in LEO, launched by the Shuttle Z, requiring about 30,000-tons of propellant to launch.

The expense was not from propellant to reach earth orbit, mostly liquid oxygen costing cents per pound, well below $0.001 billion per thousand-tons. Rather, average total cost relative to the 1300-tons originally in LEO amounted to $160,000 per pound. What Von Braun and others didn't predict in the 1940s and 1950s is that expenses would be so many orders of magnitude above fuel costs, then stay that way generation after generation, unique for any major transportation system in human history.

Rockets burn their fuel quickly enough to look a lot different from the energy consumption of an aircraft like a 747, and the payload to fuel ratio of a rocket is a few times lower. But launch costs are still a number of orders of magnitude beyond fuel costs.

The International Space Station's planned mass of about 400 metric tons at completion has an orbital kinetic energy (30 MJ/kg) of about 12 TJ. Allowing for a lot of inefficiencies, actually a total factor of around 17 as it turned out, I showed in a past thread how 5.6E7 kilowatt-hours of electricity would be more than enough to produce enough rocket propellant to launch that much mass. (Actually rocket propellant isn't electrically synthesized today, with kerosene, LH2, etc. most cheaply produced with oil, steam reforming, etc., but it doesn't matter for the point of the illustration). That number of kilowatt-hours of electricity would cost $0.003 billion at the common industrial rate of $0.06/kw-hr, with each kilowatt-hour being 3.6 MJ. Though about the size of a trailer, the ISS costs $100+ billion, as much as a giant fleet of ocean ships or a moderate-sized city on earth.

Energy expense is practically nothing compared to current costs, with the rocket propellant costs for the 62 MJ/kg that GrandMasterTerwynn mentions not the issue, rather economics like throwing away a 747 after one flight.*

* (The 62 MJ/kg is about the energy involved in reaching escape velocity before inefficiencies, neglecting losses, i.e. KE = 0.5 MV^2 with V = 11.19 km/s is 63 MJ/kg; LEO is a bit under 8 km/s, about 30 MJ/kg).

But such has been covered a lot before in past threads, particularly my first post here with the links to studies and the LEO On The Cheap online book.

In this context, one may see that the answer to the opening post question is determined primarily by when the status quo is broken. As long as equipment in space costs a number of times the cost of gold, there will never be space cities and solar system settlement.

The status quo could be broken in any decade if any one of the very few entities in the world with billions of dollars to spare funded a terrestrial mass driver and/or the right kinds of rockets like the Sea Dragon. If launch costs were reduced enough, using extraterrestrial materials could drop the cost of space equipment by further orders of magnitude. Yet that hasn't happened in the past few decades despite the technological basis having been available at least since the 1960s, so there is a simply an uncertain possibility of it happening in the future. The handful of people and entities in the entire world with the money, like Bill Gates, don't seem to overlap much with the miniscule portion of the total population having the right knowledge and motivation.

What about future technological advancements? Science-fiction depiction of low-cost space access usually relies on handwavium repulsor-like drives or the unobtanium of the classic space elevator concept. At least the latter is theoretically, scientifically possible, but the materials required for the popular full version may or may not be attained within any timeframe, even generations. A space elevator instead simply partially reducing the delta-v to orbit is possible with existing materials, as are other orbital tether concepts. Actually, such have been possible for decades.

Future technology may reduce the entry barrier for developing equipment that would break the status quo. For example, modern ultracapacitors can reduce the cost of constructing a terrestrial mass driver, i.e. one with projectiles in the metric-ton range best for passing through the atmosphere with several percent or less ablative mass losses. But such was still possible for no more than a few billion dollars even decades ago, yet never funded.

However, there is one main cause for hope. This decade is actually unique in regard to space tourism. SpaceShipOne won the $10 million Ansari X Prize in 2004 by completing two manned suborbital flights within a 2-week period, quickly refurbished between flights, after being developed for $0.025 billion. The creators of the X Prize correctly realized that a properly reusable rocket could lead to affordable spaceflight, with eventually launches only costing a few times fuel costs, like airline aircraft. With available development funds of a small fraction of a billion dollars, progress is taking a while.

However, over the coming decades, probably one or more of the new companies will send eventually thousands of people per year on suborbital space tourism flights. A little like early automobiles and early aircraft became more affordable over time, once there is enough expansion and competition, costs are likely to decrease until not many thousands of dollars per passenger at most.

Suborbital flight is not the same as orbital launches. However, particularly with the revenue stream from suborbital tourism, some companies would probably apply similar design and operating practices to orbital launch vehicles, e.g. a little like the Rocket a Day situation. For example, build one rocket like the Sea Dragon, and it launches more mass than the entire $100+ billion ISS on the very first launch, while being designed for simple manufacturing.

Due to the preceding scenario for the end result of suborbital tourism, there is more than a 50% chance of major orbital tourism sometime between 2020 and 2050, with large space hotels eventually. That would be about when the status quo is most likely to finally be broken, when even the public starts to realize that space does not have to be astronomically expensive due to fuel costs, and many investors start to see the opportunities in space. By then, launch costs could be below the long-awaited $300/lb figure, allowing major new commercial applications, like better competition with ground communication systems. Probably even Congress would finally become motivated to have NASA do more.

In that scenario, over subsequent decades, industrial capability in space expands, in a self-reinforcing cycle where more being done in space leads to more commercial interest and intelligent expenditures. Probably someone eventually builds a terrestrial mass driver to launch cargo towards orbit or to about escape velocity for as little as a few dollars a pound or less. Extraterrestrial materials are used. Satellites, exploration craft, etc. become manufactured in space. Solar power satellites may provide energy to earth.

From the infrastructure used to manufacture giant space hotels and perform other industry in space comes the first space habitats. Over the decades, thousands of temporary workers become eventually millions of permanent residents, along with their families. Space habitats have various advantages as Destructionator XIII mentioned.

Once the needed infrastructure is created, occupants manufacture more space habitats and industrial facilities. The marginal cost of new residential areas depends primarily upon the time required for the workers on one space habitat to manufacture another. Most terrestrial houses today cost the equivalent of multiple times the average worker's annual income, like someone making $40,000/year getting a $200,000 house, and the eventual space habitat situation could be no worse, or even better in the long-term. With vacuum vapor deposition construction taking advantage of plentiful energy in space, a handful of workers can create a structure to house many times their number. In the 1975 study, NASA estimated potentially "3 yr for the duplication of a habitat by a workforce equivalent to 12 percent of a habitat's population." There is enough material in the solar system to create millions of times earth's land area in artificial worlds, although obviously economic factors would mean starting small in comparison. There are practically unlimited resources: quadrillions of tons of cometary objects with ice and oil (kerogen), nickel-iron asteroids including precious metals, and much more.

When space exploration and tourism is easy, such becomes more prevalent. Each space habitat is like a self-contained city, so some don't mind spending months to years in transit. That is a lesser version of part of what people experience today on earth: Earth is voyaging through space, but people barely notice the travel as they continue with their normal lives even while traveling.

Fitting large, cheap solar reflectors on space habitats to concentrate sunlight converted to electricity for mass drivers allows some "spacestations" to be made into interplanetary transports, able to refuel at any asteroid. Mass driver equipment needed is almost trivial relative to habitat mass when they can take months in slow acceleration. Scientific outposts appear on multiple planets and moons, plus tourist centers, although the bulk of industry and population off-earth stays in space habitats.

I haven't really considered the "Discovery X" in the preceding. However, there are already aspects of space like the iridium, gold, and other heavy metals concentrated in some nickel-iron asteroids (which mainly sank to earth's core thousands of miles down after differentiation on earth, mostly unavailable in the lighter terrestrial crust).

Thousands of terawatts of power are possible to obtain with less than today's terrestrial aluminum production by building giant space solar reflectors as thin and cheap as garbage bags, far more lightweight than possible on earth, with no gravity, wind, or almost any other loading to disturb flimsy structures. That allows cheap and clean energy almost without limit. Space solar power would tend to be economically far superior to fusion reactors in most space industry even if fusion reactors were one day developed, if fusion reactor cost was comparable to existing fission reactors. Space solar power provides up to hundreds of megawatts or more per ton of aluminum reflector (assuming ~1 micron thickness or less), i.e. around a couple orders of magnitude above total terrestrial power generation with the first million tons of such reflectors.* There is more needed for electricity conversion, of course, but concentrated sunlight can be used directly for vapor deposition and melting nickel-iron asteroid metal.

* A ton of aluminum is 0.91 metric tons or about 910 kg, about 0.34 cubic meters at about 2650 kg/m^3 density. That is 340,000 / X square meters of reflector if average equivalent thickness is X microns. At 1 AU from the sun, i.e. around earth's orbit, there is 1400 W/m^2 in space, though it is a few times greater towards Mercury's orbit or about 3 times less farther out at 1.8 AU from the sun. Solar sail concepts often propose a fraction of a micron thickness, but more than 200 MW/ton is obtained for up to a couple micron foil thickness at 1 AU.

Baseline scenario:
Through the anticipated results of suborbital tourism, there is more than a 50% chance of all of the conditions of the opening post being fulfilled by around 2100, in about 100 years. That would be after the status quo was broken by 2050.

Optimistic scenario:
The status quo could be broken instead in merely the next 5 to 10 years (i.e. if a billionaire soon started funding development of a mass driver, Sea Dragon, Otrag, or other such launch system), with everything accomplished by 2030 to 2040, but such is unlikely since it never happened in the past several decades. The 100-year scenario driven by current suborbital space tourism progress is more likely.

Pessimistic scenario:
If suborbital space tourism and its expected indirect results fail to materialize, then it would be hard to say when, if ever, solar system settlement might occur. For example, perhaps the 2020 U.S. government plan would be to the 2004 plan what the 2004 plan was compared to the 1989 plan ... and such are only for a handful of people in space anyway, not focused on solving the launch cost problem. Over generations, fewer and fewer people would imagine an future in space, like expectations of the future dropped between 1950 and 2000.

Other possibilities:
Of course, for the preceding, I am not considering radical possibilities like if super-intelligent AI individuals get developed, in which case future prediction would be really hard. Indeed, if human civilization does fail to expand into space, there might still be a "second chance" for sapient intelligence if such realized how to accomplish it and did it.