Milestones to Space Settlement: An NSS Roadmap (Part 2)


Part II: Milestones to All Destinations

L1 Waystation
“Fill ‘er up!” Four views of a cislunar way station at L1 with shielded crew modules and multiple standardized docking ports for propellant depots and re-usable lunar and Mars ferries. Art: [email protected].


At every stage, certain Barriers will be encountered.


For many, the pace of space development is frustratingly slow, especially when compared to the fast pace of computer revolutions. Government agencies and even the media tend to report and explain space activities in a boring manner, if not ignoring them altogether. Space development would be furthered by greater education of the public and by stimulating and sustaining public interest over long periods of time. In retrospect, it is amazing the extent to which space is now integrated into every aspect of our civilization without people even being much aware of it.


For alleged “safety” reasons, governments are tempted to limit the ability of private individuals to organize and undertake space ventures or to voluntarily accept the risks of travel into space. If there had been such societal restraints two hundred years ago, the frontier of the American West would not have been settled then. Space development requires the freedom to voluntarily take risks and, consequently, societal aversion to risk-taking is a barrier to be resisted and countered.


Space development requires long lead times, which means long-term funding. Economics, or at least perceived economics, will always be a Barrier, both to governmental and private efforts.

(1) Governments, unfortunately, have inherent pressure to think in the short-term and perhaps just to the next election. Even if they authorize long-term programs, they are unlikely to simultaneously provide long-term funding, even if long-term funding would also result in significant savings over the life of the program.

(2) In the private sector, investors also tend to look to immediate rather than long-term profits. To encourage private investment in space activities, governments need to provide an encouraging environment, for example, by reducing or eliminating unneeded regulations, by legislating limits to liability in the case of space-related accidents, by allowing space travelers to take voluntary risks, or by providing rewards for or tax relief from space ventures.

MILESTONE 1: Continuous Occupancy in Low Earth Orbit.

Construction of continuously occupied structures in Low Earth Orbit (LEO).

The attainment of this Milestone is ongoing now.

No permanent space settlement can be constructed without there first having been accumulated (i) the technical knowledge, industrial tools, unique materials and techniques necessary to create such a novel habitat, as well as (ii) biological data about the ability of terrestrial life to survive and thrive for long periods of time outside Earth’s atmosphere and gravity.

That knowledge and expertise has been and will be acquired by the launching or construction of large structures in Low Earth Orbit (LEO). LEO is the closest place in which research can occur and techniques can be practiced, and from which escape in an emergency is most feasible.

From the U.S. Skylab, to the Soviet Mir, to the International Space Station (ISS), such crewed structures have been placed in orbit, and space stations of other countries have been long anticipated. These space stations are essentially tools, rather than ends in themselves — laboratories in which we learn how to construct in space, live and work in space, gather biological data, avoid or survive space debris, and explore scientific principles and technologies that can be developed only in space. Over time, newer equipment will be added and critical new experiments will be conducted onboard, e.g., with a variable gravity centrifuge to determine the effects of living in lunar or Martian gravity, with space solar power transmitters and receivers, with Closed or Controlled Ecological Life Support Systems, or with new power systems.

The queue for workspace and experimental time aboard the ISS is a long one. The time any space station can remain in LEO is limited by atmospheric drag and by wear and tear, but every month in which a space station is in orbit provides a wealth of new data and experience.

The International Space Station will be followed in orbit by other human-occupied facilities, such as hotels, laboratories, factories and depots. These would support space tourism and recreation, scientific research, low-gravity manufacturing, space solar power infrastructure, and refueling and repair operations, and the like. The lessons learned will be applied to later space settlements.

Further Reading:

MILESTONE 2: Higher Commercial Launch Rates and Lower Cost to Orbit.

The emergence of a sufficiently large launch market, with more efficient and reliable vehicles with faster turnaround times, or technical and operational improvements such as re-usable vehicles, or both, significantly lowering the cost of access to space.  Both higher launch rates and lower vehicle and operational costs will be required.

This Milestone will be reached in several ways:

Flight Test Demonstrations

NASA and other government-funded space agencies continue their roles in developing space transportation technology specific to achieving operational cost reduction through flight test demonstrations of technology. Examples are such U.S. test vehicles as the X-34 and X-37. These activities create “on the shelf” technology for industrial/commercial uses. This government role has proven beneficial in the aviation industry and more recently in the private space industry.

Government Contracting Practices

Government contracting practices evolve to emulate more commercially reasonable practices, which will likely dramatically lower the cost of government-funded efforts. Such practices include continuing to move from direct responsibility for managing the development of launchers and other hardware to just purchasing hardware and launch services for crew and cargo from commercial sources. With the government as a stable customer, a market is expected to be created which will encourage competition among many enterprises, existing and new, which will inevitably further reduce the unit cost of each space flight.

Progress in Launch Technology

Launch rates alone cannot be counted on to reduce launch costs (for example, if labor costs for construction and launch are too high). Improvements will occur in methods used for the design and physical construction of boosters, testing and preparing them for launch, and operating them before and during launch, which will speed and automate operations and thereby reduce cost. One significant example is the use of reusable vehicles.

Space Tourism

Space tourism develops into an industry requiring numerous launches that will lower the cost of each launch to commercially sustainable levels. Hundreds, perhaps thousands, have already made deposits on private suborbital flights. These journeys will later extend into Earth orbit and then into orbits around the Moon and back.

Commercial Facilities in Orbit

With the development of reliable and affordable space transportation, private enterprises create commercially profitable orbital facilities, e.g., hotels and factories. These facilities will be large enough to allow travelers to enjoy the feel and unique opportunities of zero gravity for extended periods, but small enough to be able to move to avoid known space debris. It is likely that transportation and facilities will evolve together, in that the availability of one will serve as a commercially justifiable rationale for the other.

Space Solar Power

A different path to achieving high launch rates and lower costs to orbit might be forged by the world’s need for power. In this case, human travel to destinations in and beyond Earth orbit would be an incidental benefit rather than a primary goal,. If and when it becomes apparent to governments that all available conventional sources of power — e.g., coal, natural gas, wind, hydroelectric, geothermal, nuclear, and ground-based solar — will be either inadequate to meet the needs of their people or that the side-effects of their use are unacceptable, they inevitably will look more closely at space solar power, or SSP (sometimes referred to as space-based solar power, or SBSP, since it involves satellites in space transmitting the Sun’s energy down to Earth.)  The SSP systems that emerge could be built by private enterprises on their own or by governments, or by some sort of partnership. Either way, those systems require and therefore will result in the high frequency of launches that drives costs down.

Other Commercial Space Applications

Other potential commercial space applications may lead to increased launch rates and decreased costs. Examples are robust communication satellite architectures, orbital servicing infrastructures, or robust global surveillance constellations.

Governmental Policies

Whether or not governments believe in, or are willing to wait for, private enterprise to lead the way, they, as a national policy choice, may commit to the building of large space outposts in Earth orbit or on the Moon which will require a number of launchers over a sustained period large enough to reduce the per-launch cost to financially practicable levels. Such governmental initiatives may be created by a desire for prestige or not to be left behind by the space initiatives of other countries, by a concern for protection from asteroids and comets, by the need for a space-based solar power system to transmit solar power to Earth, or by government uses of space for security, environmental surveillance, improved communications, or many other uses, as well as by the traditional philosophical, political and economic policy rationales long articulated by NSS and others in the space community. Such initiatives will increase launch rates and reduce unit costs.

Further Reading:

MILESTONE 3: An Integrated Cislunar Space Transportation System.

In addition to Earth-to-orbit launch systems, the creation of transportation systems and infrastructure in “cislunar space,” i.e., the space between the Earth and the Moon, resulting in regular commerce in cislunar space.

Whether developed by government agencies or private entrepreneurs, either separately or in partnership, cislunar development will likely include:

  • Reusable space vehicles carrying people and cargo between Earth orbit and lunar orbit.
  • In-space way-stations in lunar orbit or at the gravitationally balanced Earth-Moon L-1 or L-2 LaGrange Points, or all three, that each include a depot to refuel spaceships bound to the Moon or Mars or back to Earth. It is likely that the way-stations will come to have attached habitats for crews either permanently based or as a temporary refuge while en route to other destinations.
  • Reusable space vehicles to ferry people and cargo from such way-stations to the lunar surface and back.

As with sustainable Earth-to-orbit launch costs, primary keys to the development of cislunar space will be both reducing the cost of cislunar transportation and infrastructure to affordable levels and having enough of a lunar presence — i.e., enough people and enough cargo traversing cislunar space to reasonably amortize or justify the costs. To be significant enough, that lunar presence will almost certainly involve surface operations and probably a permanent presence, but a regular supply of tourists and scientists journeying just to lunar orbit and back may be a sufficient catalyst.

Even if cislunar infrastructures were initially sponsored or run by governments, cislunar operations and on-board personnel increasingly will come from an ever more skilled private sector.

The transportation systems and infrastructure developed for cislunar operations, especially if integrated with each other, will prove applicable to other in-space operations anywhere in the solar system.

Further Reading:

MILESTONE 4: Legal Protection of Property Rights.

Legal protection of property rights to provide prospective off-Earth investors and settlers with the security to take financial risks.

Successful settlement of space would be impeded if the settlers are not permitted to own real property (i.e., interest in real estate) as well as personal property, and if business enterprises are not permitted to own and run the facilities necessary to operate their businesses in extraterrestrial locations. Private individuals and groups who are considering investing their own resources to settle and develop the space frontier will need to know in advance that, if they succeed, they will be rewarded by legally enforceable recognition and protection of their claims of private ownership.

Current treaties among the nations of Earth prohibit national claims of sovereignty over bodies in space (although some nations have claimed ownership of the portions of the geosynchronous orbit arc over their territories). Therefore, it may be that nations or other terrestrial entities cannot grant ownership of property in space. However, even in the absence of modifications to such treaties, it is possible to expect that a legal regime could be established wherein reasonable claims on extraterrestrial lands, based on beneficial occupancy and development, could be recognized by terrestrial governments.

Aspects of a legal regime for property rights in space include:

  • incorporating the usual protections for individuals, businesses, and the natural environment, while also ensuring fair competition for use or ownership of property. These protections include prevention of monopolistic ownership of scarce and valuable resources as well as sensible zoning.
  • striving for the creation of economic incentives for human expansion into space, access to space for all, and protection of settlers’ rights and space resources.
  • evolving gradually, so as not to strangle a young and growing off-world presence in over-bureaucratization and over-regulation.

Note that no individual or company currently has the power to issue “titles” to uninhabited extraterrestrial real estate. NSS regards any past and contemporary offers of “title” to such lands which are not clearly denoted as symbolic and unofficial, as being unethical and deceptive.

Further Reading:

MILESTONE 5: Land Grants or Other Economic Incentives.

Economic incentives, such as “land grants,” to encourage private investment in off-Earth settlements.

Claims of title to off-Earth land will be recognized on the basis of beneficial occupancy and development. Most likely they will also require that the occupancy be intended to be permanent.

Claims could plausibly be broadened to include additional tracts large enough to make feasible subdivision and resale. Such extraterrestrial “land grants,” akin to those granted as incentives to railroads by the U.S. after the Civil War, appear to be a likely way to foster privately funded space settlements. Such measures would increase the potential for private investment in affordable space transportation and facilities and could be the difference in making settlement economically feasible. To that end, governments and the space community will be likely to develop acceptable legal mechanisms and methods of offering such land grants as an incentive for developing permanent off-Earth settlements.

Further Reading:

MILESTONE 6: Technology for Adequate Self-Sufficiency.

People leaving Earth with the technology and tools needed to settle, survive and prosper without needing constant resupply from Earth.

For a community off Earth to thrive, it cannot be dependent upon a constant resupply from Earth of critical resources. Adequate self-sufficiency will be achieved by the development of technologies and techniques to enable the settlers

(a) to meet their basic needs for air, water, power, shelter, basic foodstuffs, and the like by using local materials — e.g., soil, metals, ice and other volatiles, sunlight, and, in the case of Mars, atmosphere — such methods collectively often referred to as “in situ resource utilization” or “ISRU,” and

(b) to maintain, repair, reuse, recycle and to some extent replicate the materials and tools that constitute the daily-living amenities that are the hallmarks of modern life, such as medicines, electronics and clothing.

In building towards that goal, off-Earth settlements will initially receive regular infusions of initial infrastructures and supplies (e.g., habitats, power generating equipment, medicines, tools and electronics) until a critical mass has been assembled. That initial assemblage will enable the community to achieve adequate self-sufficiency, with a need for only occasional imports of non-critical items for which the community has not yet been able to develop its own manufacturing base. At that stage regular two-way commerce, of both people and materials, will develop between the community and Earth and other off-Earth settlements. Such a development is often characterized as the essence of a “spacefaring civilization.” Much later, as the community matures it may achieve a level of complete self-sufficiency, which, if necessary, could allow it to survive without any further imports from Earth or any other world.

Achievement of this Milestone involves two basic and contemporaneous processes:

1. Enabling Technologies

Substantial investments in a broad spectrum of enabling technologies and techniques.

These include, among many others: materials (e.g., metals, ceramics, fabrics) and materials acquisition; structural design (e.g., using metals, soils, inflatables); manufacturing and miniaturization; nanotechnology; robotics; bioengineering; in-space food production; energy systems; recycling of air and organic materials (sometimes referred to as Controlled or Closed Ecological Life Support Systems, or “CELSS”); microgravity and in-vacuum manufacturing techniques.

2. Precursor Missions

Robotic precursor missions (followed by crewed missions) to land and test, among other things:

  • a wide variety of materials exposed to the off-Earth environment for long periods of time, just as the Earth-orbiting Long Duration Exposure Facility (LDEF) once tested the durability of such materials.
  • methods and equipment for digging to expose and retrieve various raw materials.
  • methods and equipment for converting such soil and other materials into useful structural elements.
  • mechanisms to convert local soil (or atmosphere) to water and rocket fuel.
  • transportation systems for surface operations.
  • methods of radiation shielding.
  • methods of dealing with the effects of dust and electrostatics on equipment.
  • various power sources (e.g., solar, nuclear).
  • communication techniques (both local and to Earth).
  • manufacturing processes in vacuum and near-vacuum.
  • manufacturing processes in microgravity and low-gravity conditions.
  • methods of agriculture and food production in microgravity and low-gravity conditions.

These missions will become increasingly complex, as initially promising technologies and techniques are tested on ever larger scales.

Further Reading:

Proceed to Part III: Utilization of Space Technology and Resources