NASA SP-509, overview
Space Resources
Mary Fae McKay, David S. McKay, and Michael B. Duke
Lyndon B. Johnson Space Center Houston, Texas
National Aeronautics and Space Administration Scientific and Technical Information Program 1992

Superintendent of Documents, Mail Stop: SSOP, Washington, DC 20402-9328


Space resources must be used to support life on the Moon and exploration of Mars. Just as the pioneers applied the tools they brought with them to resources they found along the way rather than trying to haul all their needs over a long supply line, so too must space travelers apply their high technology tools to local resources.

The pioneers refilled their water barrels at each river they forded; moonbase inhabitants may use chemical reactors to combine hydrogen brought from Earth with oxygen found in lunar soil to make their water. The pioneers sought temporary shelter under trees or in the lee of a cliff and built sod houses as their first homes on the new land; settlers of the Moon may seek out lava tubes for their shelter or cover space station modules with lunar regolith for radiation protection. The pioneers moved further west from their first settlements, using wagons they had built from local wood and pack animals they had raised; space explorers may use propellant made at a lunar bass to take them on to Mars.

The concept for this report was developed at a NASA-sponsored summer study in 1984. The program was held on the Scripps campus of the University of California at San Diego (UCSD), under the auspices of the American Society for Engineering Education (ASEE). It was jointly managed by the California Space Institute and the Lyndon B. Johnson Space Center, under the direction of the Office of Aeronautics and Space Technology (OAST) at NASA Headquarters. The study participants (listed in the addendum) included a group of 18 university teachers and researchers (faculty fellows) who were present for the entire 10-week period and a larger group of attendees from universities, Government, and industry who came for a series of four 1 - week workshops.
The organization of this report follows that of the summer study. Space Resources consists of a brief overview and four detailed technical volumes: (1) Scenarios; (2) Energy, Power, and Transport; (3) Materials; (4) Social Concerns. Although many of the included papers got their impetus from workshop discussions, most have been written since then, thus allowing the authors to base new applications on established information and tested technology. All these papers have been updated to include the authors' current work.

This overview, drafted by faculty fellow Jim Burke, describes the findings of the summer study, as participants explored the use of space resources in the development of future space activities and defined the necessary research and development that must precede the practical utilization of these resources. Space resources considered included lunar soil, oxygen derived from lunar soil, material retrieved from near-Earth asteroids, abundant sunlight, low gravity, and high vacuum. The study participants analyzed the direct use of these resources, the potential demand for products from them, the techniques for retrieving and processing space resources, the necessary infrastructure, and the economic tradeoffs.
This is certainly not the first report to urge the utilization of space resources in the development of space activities. In fact, Space Resources may be seen as the third of a trilogy of NASA Special Publications reporting such ideas arising from similar studies. It has been preceded by Space Settlements: A Design Study (NASA SP-413) and Space Resources and Space Settlements (NASA SP-428).
And other, contemporaneous reports have responded to the same themes. The National Commission on Space, led by Thomas Paine, in Pioneering the Space Frontier, and the NASA task force led by astronaut Sally Ride, in Leadership and America's Future in Space, also emphasize expansion of the space infrastructure; more detailed exploration of the Moon, Mars, and asteroids; an early start on the development of the technology necessary for using space resources; and systematic development of the skills necessary for long-term human presence in space.
Our report does not represent any Government-authorized view or official NASA policy. NASA's official response to these challenging opportunities must be found in the reports of its Office of Exploration, which was established in 1987. That office's report, released in November 1989, of a 90-day study of possible plans for human exploration of the Moon and Mars is NASA's response to the new initiative proposed by President Bush on July 20, 1989, the 20th anniversary of the Apollo 11 landing on the Moon: "First, for the coming decade, for the 1990s, Space Station Freedom, our critical next step in all our space endeavors. And next, for the new century, back to the Moon, back to the future, and this time, back to stay. And then a journey into tomorrow, a journey to another planet, a manned mission to Mars." This report, Space Resources, offers substantiation for NASA's bid to carry out that new initiative.


Future space activities may benefit from the use of natural resources found in space: energy from the Sun, certain properties of space environments and orbits, and materials of the Moon and near-Earth asteroids. To assess this prospect and to define preparations that could lead to realizing it, a study group convened for 10 weeks in the summer of 1984 at the California Space Institute at the University of California at San Diego. Papers written by this study group were edited and then recycled through most of the contributors for revision and updating to reflect current thinking and new data on these topics. This is a summary report of the group's findings.

The sponsors of the study-NASA and the California Space Institutecharged the study group with the task of defining possible space program objectives and scenarios up to the year 2010 and describing needed technologies and other precursor actions that could lead to the large-scale use of nonterrestrial resources. We examined program goals and options to see where, how, and when space resources could be of most use. We did not evaluate the longrange program options and do not recommend any of them in preference to others. Rather, we concentrated on those near-term actions that would enable intelligent choices among realistic program options in the future. Our central conclusion is that near-Earth resources can indeed foster the growth of human activities in space. Most uses of the resources are within the space program, the net product being capabilities and information useful to our nation both on and off the Earth.
The idea of using the energy, environments, and materials of space to support complex activities in space has been implicit in many proposals and actions both before and during the age of space flight. As illustrated in figure 1, the deep gravity well of the Earth makes it difficult and expensive to haul all material supplies, fuel, and energy sources into space from the surface of the Earth; it is clearly more efficient to make maximum use of space resources. Up to now, however, our ability to employ these resources has been limited by both technology and policy. Studies and laboratory work have failed to bring the subject much beyond the stage of speculations and proposals, primarily because until now there has been no serious intent to establish human communities in space.
With progress in the Soviet program of long-duration manned operations in Earth orbit and with the coming of an American space station initiative, the picture appears to be changing. The present study is one step in a process laying groundwork for the time when living off Earth, making
large-scale use of nonterrestrial resources, will be both technologically feasible and socially supported.

Findings of the Summer Study

The 18 faculty fellows who participated in the summer study organized themselves into four groups. The focus of each group corresponded with that of a 1-week workshop held in conjunction with the summer study and attended by 10 to 20 experts in the target field. The first working group generated the three scenarios that formed the basis of the subsequent discussions. The other three groups focused on these areas of inquiry:

In what follows, our findings are presented in the order of these topics, but they are offered as findings of the summer study as a whole. Integrated in these findings are the views of the faculty fellows and the workshop attendees.

Future Space Activities

Before we could evaluate the benefits and opportunities associated with the use of space resources, we had to consider what might be going on in space in the future. The target date defined for this study, 2010, is beyond the projection of present American space initiatives but not too far in the future for reasonable technological forecasting. The U. S. space program is now set on a course that can carry it to the end of this century, with increasing capabilities in low Earth orbit (LEO) and geosynchronous Earth orbit (GEO) and modest extensions into deeper space. At the present rate of progress, there would not be much new opportunity to exploit nonterrestrial resources before the year 2000.
A typical plan for space activities is illustrated in figure 2, which shows a sequence of milestones leading to human enterprises in LEO, in GEO, and on the Moon, plus automated probing of some near-Earth asteroids and of Mars. In this plan, most of the space activity before 2010 is concentrated in low Earth orbit, where the basic space station is expanded into a larger complex over a period of 20 years. In geosynchronous Earth orbit, an experimental platform is replaced in 2004 by an outpost to support manned visits leading to a permanently manned station by 2012. Until the year 2010 only unmanned missions are sent to the Moon. In that year, nearly 20 years after the establishment of the space station, a small lunar camp is established to support short visits by people. In this plan, the only American missions to Mars in the next 40 years are two unmanned visits: a sample return mission and a roving surveyor.
It is clear that, if the plan in figure 2 is followed, natural resources from the Moon, Mars, or other planetary bodies will not be used until at least 2016.
If we consider the plan in figure 2 to be our baseline, then figure 3 illustrates an alternative departing from that baseline in the direction of more and earlier use of nonterrestrial resources. In this plan, a growing lunar base has become a major goal after the space station. Lunar and asteroidal resources would be sought and exploited in support of this goal rather than for any external purpose. The establishment of a lunar camp is moved up 5 years to 2005 and advanced lunar base is in place by 2015.In this plan, lunar resources are used to support the construction and operation of this base and lunar-derived oxygen is used to support transportation to and from base. Asteroidal material from automated mining missions would also contribute to supporting these space operations after 2015

Figure 4 shows a different departure from the baseline. Here, the objectives are balanced among living off Earth, developing near-Earth resources for a variety of purposes, and further exploring the solar system with an eventual human landing on Mars. In this alternative scenario, a LEO space station, a small GEO outpost, and a small manned lunar station are all in operation by 2005, with a manned Mars visit and establishment of a camp by 2010, some 12 to 14 years earlier than in the previous plans. Automated asteroid mining and return starts by 2010. The focus of this program is longer term than that of the program diagramed in figure 3. By building up a balanced infrastructure at various locations, it invests more effort in activities whose benefits occur late in the next century and less in shorter range goals such as maximizing human presence on the Moon.

These three scenarios, the baseline and two alternates, have served as a basis for our discussion of the uses of nonterrestrial resources. None is a program recommended by the study group, since that was not our charter. They are merely illustrative examples of programs that, we believe, might materialize over the next two decades as a result of national or international trends in space. The two alternate scenarios assume some acceleration and focusing of American efforts in space, as happened during the Apollo era, while the baseline scenario assumes a straightforward extrapolation of our present program, with only modest budget growth and no particular concentration on the use of nonterrestrial resources.

Heavy Lift Vehicle
An unmanned heavy lift launch vehicle derived from the Space Shuttle to lower the cost of transporting material to Earth orbit would make it feasible to transport to orbit elements of a lunar base or a manned spacecraft destined for Mars. Its first stage would be powered by two solid rocket boosters, shown here after separation. Its second stage would be powered by an engine cluster at the aft end of the fuel tank that forms the central portion of the vehicle. All this pushes the payload module located at the forward end. This payload module can carry payloads up to 30 feet (9.1 meters) in diameter and 60 feet (18.3 meters) in length and up to 5 times as heavy as those carried by the Shuttle orbiter.
Artist-Dennis Davidson

Energy, Power and Transport

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