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Small steps now in key technologies for sustainable space development can lead to space-based solar power and more technologies that enable long-term space settlement. (credit: NASA)

The future of space economics and settlement

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The Apollo Moon landings in the 1960s and ’70s have often been compared to the Lewis and Clark expedition into the then-unknown wilds of the Louisiana Purchase. The analogy is quite accurate in at least one respect. Lewis and Clark made a lot of camps, did a lot of observation, took a lot of notes, made maps, collected samples, and, having completed their exploratory efforts, returned whence they came. The Apollo astronauts did much the same, leaving behind six “campsites” but no long-term useful infrastructure except some laser reflectors.

The pattern of these past 40 years or so is that NASA can only afford to do one big human spaceflight project at a time while it works on the next one.

The US threw together a sizeable bureaucracy to accomplish the Moon landings. When public enthusiasm for brief lunar trips cooled to the point where their expense became politically unsustainable, this bureaucracy looked for something else to do that was sufficiently unlike the Moon landings but was affordable on NASA’s reduced rations and which could employ leftover Apollo hardware. That was Skylab, America’s first low Earth orbit (LEO) space station. When the legacy hardware ran low and political enthusiam for the project also waned, Skylab was allowed to fall into the Australian outback. It joined the abandoned lunar campsites on the list of America’s “space ghost towns.”

Other programs would follow in the same vein: the Space Shuttle, International Space Station, and Constellation, developed and later abandoned or threatened with abandonment. Now NASA is pursuing the Space Launch System (SLS) and Orion as centerpieces of the Journey to Mars, with history threatening to repeat itself.

The pattern of these past 40 years or so is that NASA can only afford to do one big human spaceflight project at a time while it works on the next one. In order to operate the new project, the previous project has to be abandoned as there is insufficient money in NASA’s long-term-shrinking budget to keep things going. The US human presence in space is one of periodic substitution, not one of growth. The NASA human spaceflight “program” is, in effect, one of creating serial space ghost towns.

Even NASA’s noisiest boosters, inside and outside the agency, implicitly recognize this. There are significant constituencies in the space enthusiast community who want nothing so much as a return to the Moon. There are others who insist with equal passion that NASA’s next marquee destination must be Mars. Many in both camps see the $3 billion annual ISS budget as the pot of gold they need to see their dreams to fruition. Thus, there is a considerable combined constituency for rendering ISS the next in America’s inglorious list of space ghost towns.

One notable problem with this view is that it fails to reckon with the long-term decline in NASA’s budget as a percentage of total federal outlays. NASA’s budget peaked at nearly 4.5 percent of the federal budget in 1966. A decade later it had fallen to 1 percent. During the Carter, Ford, and Reagan Administrations, NASA’s budget fell well below the one-percent mark, only getting back to that level during the presidency of George H.W. Bush as he chose space to demonstrate that he was not entirely lacking in that “vision thing,” as his detractors maintained. Beginning with the Clinton Administration, though, a steady, bipartisan decline began again down to the current level of approximately 0.5 percent of federal spending. Neil DeGrasse Tyson’s tub-thumping notwithstanding, the likelihood is for NASA’s budget to continue its longstanding trend of secular decline, not some sudden resurgence to the good old days of one-percent budgets.

The sad fact is that while NASA is still capable of creating a new space ghost town by shutting down and de-orbiting ISS, it seems finally to have run out of sufficient wherewithal to build the next future space ghost town.

SLS and Orion, combined, have a budget rougly equal to that of ISS. But their development schedules, particularly that of SLS, is such that they will not fly humans until well into the next decade.

SLS’s initial configurations will be notably inferior in lift capacity compared to both the long-dead Saturn V and the more recently cancelled Ares V. That makes SLS too puny to be a single-launch rocket even for Moon missions, never mind Mars. SLS’s production rate and planned launch cadence are such that any multiple-launch mission is pretty much a non-starter as well.

The so-called Block 2 version of SLS would be a somewhat better performer but not by enough to matter. The key component not present in the earlier versions is an advanced strap-on booster that NASA has already delayed indefinitely and for which no development money seems to be in the offing. Nor does the projected SLS-Orion development budget yet include any funds to develop landers or in-transit habitation modules needed for cislunar or deep space missions.

Even if the forces of NASA reform could somehow crush Congressional opposition, the victory would be largely pyrrhic.

So what is to be done? There are some who think a thorough overhaul of NASA would put things back on whatever they are inclined to regard as “track.” Suggestions include abandoning the cost-plus contracting that has become normative, selling off unneeded infrastructure, and closing some of the numerous NASA centers. But NASA business as usual is fiercely defended by many in Congress from both parties. NASA centers, in particular, will be defended with Stalingrad-like ferocity.

Even if the forces of NASA reform could somehow crush Congressional opposition, the victory would be largely pyrrhic. Following the commercial cargo and crew model for all NASa programs, consigning SLS and Orion to the Smithsonian, and closing whole centers would simply allow NASA a bit more room to maneuver within budget constraints that no political will exists to ease.

In the wake of even a sweeping victory by some putative “Rebel Alliance,” NASA would still find itself seriously hemmed in by budget realities. Some kind of presence in LEO could be preserved after ISS simply gets too old and decrepit, most probably as lessees for all or part of one of Bigelow Aerospace’s planned commercial space stations. Toeholds could also be re-established on the Moon and perhaps even on Mars, especially if NASA leaves the latter project mostly to SpaceX.

But NASA-sponsored human presence anywhere off-planet will be constrained by how much NASA can spend to keep a certain small number of personnel fed and otherwise supplied, even if the supplying and crew rotation chores are left entirely to SpaceX, Orbital ATK, Sierra Nevada, and others. The crew complements of off-world NASA outposts will not be large and ongoing budget limits will keep them small.

But the Moon and Mars are not the only places with constituencies, both inside and outside NASA, for establishment of human presence. Some wish to see space stations built at one or more of the Earth-Moon Lagrange points, like L1 and L2.

And, on both the Moon and Mars, there’s no consensus on where to go. On the Moon, many urge that any settlement be at one or the other of the lunar poles where the Moon’s riches of water ice are thought to be concentrated and where solar power can be nearly constantly obtained. Some would like to see both poles occupied. Others most favor an astronomical base in the center of lunar farside, cut off from the electromagnatic interference of nearby Earth. Others have spoken up for occupying one or more of the many apparent natural lava tubes that dot the lunar nearside so as to get the benefit of underground radiation protection without requiring extensive civil engineering. Mars, for its part, also has its own lava tube lobby, plus those who favor places near the Martian northern polar cap or one or more of its formidable volcanic mountains.

An alternative model

The one thing that is abundantly clear is that “all of the above” is not an option if the NASA budget is to be the primary or sole support of such efforts, even if all of NASA’s currently alleged faults are repaired. The NASA budget is an undersized blanket. Tug it in one direction to keep your shoulders warm and your feet are then exposed. Even a ferociously efficient future NASA would reach the limits of the human space activities it could realistically support on an ongoing basis very quickly. After that, any new “town” in space would require turning an existing outpost into another space ghost town.

So, what is to be done?

The obvious answer is to cease basing future plans on the ability of a decidedly finite NASA budget to support them and seek alternatives that promise to be, at the minimum, self-supporting or, better still, self-expanding. Non-profit, government-backed space initiatives, in short, must become the minor exceptions and profit-making business enterprises must become the norm for human presence and activity in space.

How do we do that? As a start, we can look at what a vigorous, growing space economy might look like once it is well past the initial bootstrapping phase. With this destination in our mind’s eye, we can then turn to the question of how we can, stepwise, get from where we are now to where we want to be.

The overarching theme of trade in such a future highly- and diversely-populated solar system will be simple: energy moves outbound and mass moves Sunward.

We should first note that the orbit of Mars marks a sort of border of some economic significance. The vast majority of the readily exploitable energy in the solar system lies inside it, in the sense that this is the region where solar energy collectors, whether thermal or photovoltaic, are most efficient and the solar particle and photonic fluxes are strongest.

Beyond Mars orbit, on the other hand, lies most of the readily exploitable mass in the solar system: the main asteroid belt, nearly all the planetary moons in the solar system, the rings of Saturn, the Kuiper Belt, and the Oort Cloud.

I believe humans will eventually live and work in all these places. The overarching theme of trade in such a future highly- and diversely-populated solar system will be simple: energy moves outbound and mass moves Sunward. The largest economic base for the inner Solar Sytem will be the collection and transmission of solar-derived energy. Some of this energy will be used locally in the inner solar system, but much will be directed outward to customers whose own economic base is the gathering, refining, and transport of industrial materials both within the outer solar system and Sunward, toward those who will transform them into more energy collection and transmission infrastructure.

In both the inner and outer solar system, significant quantities of gathered and transported mass will also be used for construction of human habitations. Some of these will be located on or under the surfaces of moons and planets. But most, in my view, will be located in free space, orbiting some planet or moon or the Sun itself.

Why would free space habs predominate? Quality of life. The human organism evolved in a one-g gravity field. One-g is natural to us and free space habs can be spun to produce one-g if they are built with sufficient diameters to render coriolis forces and differential g-forces over an occupant’s body negligible. We know that zero-g has deleterious effects on the human body. We don’t yet know what various levels of fractional gravity will do to us. We will eventually find out, but building one-g habs sidesteps the whole issue.

In similar fashion, the non-trivial problem of dust control on lunar and planetary surfaces is rendered mostly moot if the overwhelming majority of space-dwelling humans live in manufactured free space habitats.

Radiation shielding can be straightforwardly provided by use of glassified asteroidal material and/or water in conformal tankage. There is a fair amount of water to be obtained from many asteroids, and beyond that, there are cometary nuclei to be exploited and even the outer ring of Saturn, which the moon Enceladus conveniently keeps feeding.

We don’t yet have super-efficient, low-maintenance, closed-cycle life support systems, but these will be needed anywhere humans go in space, both free space and planetary or lunar surfaces alike. It is an item that must be addressed regardless of address, so to speak.

What will the spaceships of this future spacefaring human civilization look like? The ones that transport humans will most likely be rotating habs with engines. The ones that transport freight will be bins or tanks with engines. For people looking for the lowest-cost ride on well-traveled routes, these ships could operate as Aldrin cyclers. For others in a hurry or with uncertain itineraries, there would be ships that run their engines full-time.

What will those engines be? If “EM-drives” turn out to actually work, they’ll be EM-drives. Assuming no breakthrough physics, though, Sunward traffic will probably be driven by improved and enlarged versions of the ion thrusters in use today.

Asteroid mining need not be initially proved out on actual asteroids. There is, regrettably, plenty of junk already in orbit.

The favored reaction mass for such thrusters will, in my view, most probably be argon rather than the xenon used in most current applications. Xenon is comparatively rare and expensive. Argon, though, is roughly half a percent of Earth’s atmosphere and nearly a full percent of the Martian atmosphere. It is already produced in industrial quantities here on Earth as a by-product of air liquefaction. The same can apply on Mars.

Argon might turn out to be a comparatively rare case of a mass commodity moving outbound in regular commerce from the inner to the outer solar system. It could provide a long-term economic basis of support for Martian surface colonies as well, for those who want to brave low gravity and pervasive dust on a daily basis. It would also provide a long-term economic basis for both terrestrial and Martian launch service enterprises needed to lift argon into space. On Mars, this might be rockets powered by ISRU-produced liquid ozugen and methane or, eventually, it could be via a Martian space elevator.

Outbound traffic would more likely be powered by lightsails or by solar wind sails. Solar wind sails use a radial array of charged wires to create a field against which solar protons can usefully push. Solar wind sails and/or Aldrin cyclers would probably be the choice for outbound cargoes of argon from Earth and Mars. For human transport, the greatest speed might be possible using laser-boosted lightsails. The energy industry of the inner solar system will probably transmit a large percentage of its product to ships and “stationary” customers in the outer solar system via phased arrays of lasers. The rest will probably go via microwave or terrahertz radiofrequency beams formed by huge phased arrays.

Small steps for giant leaps

So how do we get there from here? Start small and work up.

Asteroid mining, for example, need not be initially proved out on actual asteroids. There is, regrettably, plenty of junk already in orbit. One proposal of how to deal with randomly tumbling space rocks is to enclose them in a sealable envelope into which a small amount of gas is then released, which eventually de-tumbles the rock. This approach could be tried out cheaply at small scale using a tumbling piece of space junk as a target.

Refining asteroids into useful materials might well be done by using electron beams to cut off material, and convert them into plasma. This would then be fed, via electromagnetic fields, into a device that is basically an oversized mass spectrometer that sorts out the pure elemental constituents.

Alternatively, lasers could slice asteroidal material into pieces that could individually be zone-refined into pure billets of whatever the dominant element present is. Emitted gases, such as vaporized water, could be captured. The impurities culled from the inital zone refining pass could be subjected to additional passes to produce more pure elemental materials in descending order of their presence in the source asteroid.

Again, these processes could be tried out inexpensively and at small scale on space junk targets of convenience. Once the processes prove out, an initial modest refining facility could begin commercial operation in Earth orbit. There is plenty of space junk to be chased down and processed. The most fruitful initial lode to attack would probably be the graveyard zone above geostationary orbit, where old comsats go to die.

There are obvious legal impediments to grabbing and recycling just any random piece of space junk, but the US could get the ball rolling by allowing salvage by bid of most of its own dead satellites and other space detritus to which clear US title can still be established. Perhaps the salvaging of dead US intelligence satellites would be limited to American firms only.

The Russians, who account for the majority of space junk currently extant, might well go along with such a regime. They’re hard up for cash these days; a condition which is likely to be true indefinitely. Letting Western space junk recyclers bid for salvage rights to their dead civilian satellites might just be appealing to them. Making a little found money is certainly preferable to being sued the next time some Soviet-era bit of space flotsam happens to take out another country’s operational satellite.

Lewis and Clark were followed by legions of settlers. The Apollo moonwalkers were not.

Space manufacturing and space solar power are also businesses that could start small and work up. A space factory could start as a tenant business in one of Bigelow’s planned LEO space stations. Initially it might not even manufacture very much. But just having someone in orbit who could assemble, check out, and launch a deep space probe designed by an academic institution or a prospector probe designed by an asteroid mining company that was shipped to space in pieces, would radically simplify the design process. No need for complex hinged components and troublesome motors and batteries whose sole job is automated deployment of a probe’s components and afterwards become just dead weight. Think about how much more likely, say, the James Webb Space Telescope would be to work if it didn’t depend critically on all sorts of “butterfly-escaping-chrysalis” steps that are expensively automated and have no failure margin.

I am struck by how many proposals are submitted every time NASA runs another of its competitions for science missions. The submissions typically number in the dozens and only one or two get picked. The competition is fierce not least because designing, building, and testing a complex probe is expensive, and NASA is the only source of funds for such projects that run in at least the hundeds of millions or dollars.

But what if there was an orbital workshop that could assemble a simpler design from a kit of parts cheaply and compactly launched as part of a routine, non-dedicated resupply launch and then, once assembled, send it on its way under solar-electric power? What if some of the bulkier, simpler structural stuff could even be fabricated on-orbit? How much would your project cost then? Eight figures maybe? Seven? It’s a lot easier to find a benefactor with a few million who likes your idea—especially if it includes naming rights—than it is to find one with hundeds of millions to burn.

Similarly, the first orbiting solar power satellite (SPS) could be a modest affair, at least compared to the kilometers-wide fantasy SPS’s of sci-fi. Build it as linkable modules on Earth, pack it tightly, then send it to our space factory for assembly, checkout, and deployment.

The first job of such a “micro-SPS” would be to provide beamed power for the engines of all manner of space tug vehicles, including prototype asteroid miners as they pursue dead satellites in Earth orbit as already outlined. Such powersats don’t have to be in GEO to do their jobs, but rather there just have to be enough of them in whatever orbit is chosen so that one is always in the line of sight to any vehicle needing their services.

Once again, the key to the human future in space is to start small, start cheap, and start close. There’s no point hunting asteroids to mine until all the orbital space junk is exhausted. Once it’s time to graduate to real asteroids, the closest, in terms of delta-v, should be visited first. That means the Earth-grazers and the inner solar system asteroids will be first in the crosshairs. There is no need to go clear out to the main belt until all the low-hanging asteroidal fruit is picked.

Lewis and Clark were followed by legions of settlers. The Apollo moonwalkers were not. The Moon is a far harsher environment than the American West and cannot be reached with a team of horses or yoke of oxen and a Studebaker or Conestoga wagon. The American West was a comparatively easy place for ordinary people to go seeking fortunes or merely a life better than the one they already had. Neither the Moon nor anywhere else in space is so accessible.

But we don’t have to start with the Moon. We can do useful things in LEO that will pave the way for going incrementally farther out and doing incrementally more. Seeding modest in-space businesses that can exhibit steady growth over time means that, when it is time to go in earnest back to the Moon and on to Mars, we will be able to do so en masse and in style, and not as tenuous remittance men, tethered to the politically fragile budget of a single government agency.