The Value of the Moon

by Paul D. Spudis

  Figure 9.3. Deep space staging node located at Earth-Moon L-1, about 60,000 kilometers above the center of the lunar near side. A staging node can serve as the jumping-off point for missions to the Moon and planets; it contains a habitat for temporary layovers and a propellant depot for the refueling of spacecraft. Future Orion spacecraft shown docked to the transport node. (Credit 9.3)

  In the lunar architecture described previously, I call for the building of a 30-ton-class reusable lunar lander (see figure 7.1). The purpose of this vehicle is to transport people to and from lunar orbit. By eliminating the need for extended life support, we can make this vehicle smaller than the proposed Altair lander called for by the Constellation architecture. Here, the issue of reusability largely revolves around engine performance and maintenance. A throttleable version of the venerable RL-10 cryogenic engine, used today in the Centaur upper stage, can perform multiple restarts and is a good engine on which to base the creation of a reusable lander. At some point, we will have to change out engines on the reusable vehicles, but they can be made part of a modular system serviceable by suited astronauts and teleoperated machines on the lunar surface. A reusable lander would spend about half of its time on the Moon and the other half in space, at the appropriate staging node, either in low lunar orbit or at one of the L-points. It would be designed to reach its space node with half of its fuel remaining. This permits the lander to make the next descent and landing and then refuel on the Moon with propellant made from lunar water.

  Passive, space-based assets require much less work to maintain. Staging nodes, where vehicles can meet and interact to transfer crew, collect cargo, refuel, and the like, will become part of the transportation system. These nodes are actually miniature space stations, complete with their own power, thermal, and attitude control systems. They are much less complex than the ISS, in that they are designed only for a single specialized use and are unoccupied most of the time. However, some maintenance will be needed to keep the nodes functioning correctly. This may include refueling the attitude thrusters and maintaining the electrical and thermal control systems. Transport nodes can be based in several localities, including LEO, an L-point, and in low lunar orbit. The nodes may or may not be associated with a fuel depot.

  An orbiting fuel depot is a new technology that can increase the size of payloads placed on the Moon and throughout cislunar space. However, we have much to learn about their construction and operation. The biggest difficulty is learning how to deal with the “boil-off” of extremely low temperature cryogenic liquids. Liquid oxygen boils at —183°C, and liquid hydrogen boils at —253°C. Although we can shield storage tanks from direct exposure to solar illumination with screens, passive thermal radiation from the depot itself will heat these liquids enough to cause evaporation. This problem must be solved to create a permanent space transportation system. Although we do not know how to mitigate this issue at the moment, the solution will probably involve capturing the boil-off gases and recondensing them into liquid.

  One way to minimize loss from boil-off is to keep the propellant in a more stable form until it is actually needed. We can transport propellant throughout cislunar space in the form of water, a substance that is easily stored and transferred, and then cracked into the cryogens just before a spacecraft is scheduled to arrive. This would require that the fuel depots of the future also contain a propellant processing system. Such a system would include large solar panels, cryogenic plants, and storage facilities. With this capability, the fuel depot becomes a more complex space station, but it also decentralizes operations throughout the entirety of cislunar space. Note that we will still need these cryogenic processing facilities on the lunar surface in order to refuel arriving spacecraft, along with their obvious importance to the crews who live there.

  A complete cislunar transportation system consists of an Earth to LEO transport, multiple staging nodes, fuel depots, transit spacecraft, landers, and the lunar outpost. Such a system permits routine access to the Moon and to all other locations within and throughout cislunar space. For the first time, we will be able to move people and cargo where they are needed, anywhere in cislunar space. Currently, communications satellites at GEO are inaccessible for visits by people. With the new system described here, we can travel to GEO to repair, maintain, or even build new distributed satellite systems of unprecedented power and capability. A communications satellite the size of the ISS could provide uninterrupted communications coverage over a hemisphere, rendering the entire terrestrial cell phone network obsolete in an instant. It could provide enough bandwidth to accommodate thousands of channels of high-definition video, Internet traffic, and personal messaging. Three such complexes would link the entire world with these capabilities; it would generate new wealth and provide endless possibilities for innovation and technology development. In addition, we will be better able to protect sensitive surveillance equipment and other strategic assets. Such capability will make the world safer, in that we would not be rendered blind in the event of aggression and we could better respond to crises, both natural and man-made, that may develop on Earth. The upgrading and enhancement of scientific sensors would also be possible, including such difficult tasks as the servicing of the soon-to-be-launched James Webb Space Telescope, to be located at the Sun-Earth L-2 point and inaccessible to servicing spacecraft with existing systems.

  I began this academic journey by explaining how we can use lunar material and energy resources to create a new spacefaring capability—the creation of a permanent transportation infrastructure in space. Such a capability can satisfy all of our requirements to maintain and enhance service satellites, and to open up the Moon (and indeed, the entire solar system) for exploration and development. The rest of the journey—the one that you may envision—is now possible.

  Exports from the Moon

  Until now, I have mainly focused on the development of lunar resources to obtain a foothold on the Moon, but is there anything on the Moon that has economic value elsewhere, other than at a lunar outpost? What lunar exports might become profitable in the future and how might such markets, be they private or government, be developed? Is there a “killer app” in lunar resources, a product or service that can create new wealth and actually give us a return on our investment in spaceflight and infrastructure? Many people and nations are keenly aware of the possibilities to realize a profit, and are considering ways to exploit an advantage.

  The most obvious lunar product of economic value is water. As previously described, water is an extremely useful substance in space: It can support human life, it serves as a medium for energy storage, and it can be used to make rocket propellant. Thus, for spacefaring nations and companies, by having the ability to purchase useable water already in space, it negates the requirement for them to bring water along from Earth. This option makes their space missions more productive, more routine, and more profitable. A space-based market for water will probably emerge first. Special importance will be given to the availability of propellant at the orbital fuel depots. A good policy would be to husband any surplus water at fuel depot-transport nodes for sale or barter with other spacefaring nations. Such fuel sales could be used to support the flights of other countries on their cislunar missions. It will also find use as fuel for attitude control-orbital maintenance thrusters. At the moment, such thrusters use storable propellant, but if a space-based source for cryogens became available, the satellite builders of the world would soon modify their systems to enable its use.

  The idea of generating electrical power in space for transmission back to Earth to be sold commercially has been a staple of lunar development schemes for some time. The Solar Power Satellite (SPS) concept has always faced a major stumbling block; the high cost of launch from Earth of the massive solar arrays make it financially infeasible.11 A permanent presence on the Moon changes that picture. Solar arrays can be manufactured from lunar surface materials and launched into cislunar space at lower cost, due to the lower gravity o
f the Moon.12 In fact, it is likely that if financially viable SPS systems ever become available, they will be made possible only through the use of lunar resources.

  An extreme variant of this idea proposes to make the solar arrays in place on the Moon. A small rover rolls along the ground, fabricating amorphous solar cells that are connected and wired together as the rover slowly moves across the lunar surface, manufacturing a solar array that can be tens to hundreds of square kilometers in extent. In the equatorial zones of the Moon, gigantic solar panels farms, with enormous gigawatt-level power output, can transmit to space or directly to Earth via lasers or microwaves. Receivers in either location can collect this power and offer it at commercially competitive rates. To receive constant solar illumination, this system would require the construction of two solar array farms on the equator on opposite sides of the Moon. Seemingly something from science fiction, if undertaken at the appropriate scale, such energy production on the Moon (which has been analyzed economically) is workable.13

  The possibility of extracting helium-3 from the lunar soil to power fusion reactors on Earth for commercial power generation may be possible within the next few decades, once a determination is made whether such a plan is technically viable or not.14 If so, helium-3 mining could be a competitor to large-scale solar power generation on the Moon. It would require a significant amount of surface infrastructure to produce commercially useful quantities of the fuel. One wild card in the helium-3 story is that we do not know how much of it might be contained in the polar cold trap volatiles. If these volatile substances are of cometary origin—and analysis of the LCROSS data suggests that they are—helium-3 might be present at roughly solar abundance.15 Thus, it could be easier and less costly to extract large amounts of helium-3 from polar ice, than from equatorial mare regolith. This is a missing piece of information that will be answered once we are able to send a properly instrumented rover into the polar dark areas on the Moon.

  Other lunar products may eventually become economically attractive. We are not imaginative enough to envision them all. The earliest product to have monetary value from export comes from the first product that we make on the Moon—water, in all of its forms. To move through space requires the expenditure of energy in the form of rocket firings. Thus, the freedom of space is energy change. Energy change is a rocket firing. Rocket firings require propellant. To make propellant, we need water. And water is available in large quantity from the polar cold traps of the Moon. Thus, water is the currency of spaceflight. By establishing a resource processing facility on the Moon, we position ourselves to participate in the world markets of the future.

  Learning to Live and Work on Another World

  Several skills must be mastered and many different technologies must be developed if humanity is to become a multiplanetary species. One recommendation of the 2009 Augustine Committee was to table the notion of selecting destinations in space such as the Moon or Mars and instead work on developing the technology to go anywhere.16 Then, when we have the technology necessary, we ramp up and go to the planets. This approach, called the “Flexible Path,” was quickly embraced by the administration that chartered the committee. Adoption of the Flexible Path was an attempt to distract national attention from the fact that our civil space program was going nowhere.

  The largest and most comprehensive expansion of space technology in history was the product of the Apollo program, the antithesis of a “no-destination” effort. The truth is, we get more technology development as a result of the need to solve specific problems, problems that arise when we try to do something or go to someplace in space. Confronted with specific issues and needs, technical solutions must be developed or we go nowhere, learn little, solve nothing, and become vulnerable. Historically, a pressing need for answers drives innovation much more quickly and efficiently, than does tinkering around in a hobby shop.

  We go to the Moon to learn how to use what it has to offer. One of those offerings is its virtue as a world on which to live and work. Humans have almost no experience with this. The Apollo missions fifty years ago allowed a few people to experience the Moon for a few tens of hours each. From that experience came a dream that has never faded: that a great adventure and future awaits the first people who attempt to make life in space an extended experience. The Moon is our first step. The struggles humans will face learning to survive in a hostile, foreign environment are difficulties we need to face and solve before we venture further into the solar system. Learning how to live and work on the Moon involves both humans and machines, together, coping with an environment of low gravity, vacuum, thermal extremes, and hard radiation. We can design equipment to use and to protect us for short durations, but we need to understand how well these instruments and machines work on timescales of months and years. Using the Moon as a natural laboratory will teach us how to arrive, survive, and thrive on other worlds.

  Besides survival, we also need to learn how to explore and study alien worlds. We have a vague idea that such an exploration template somehow involves both humans and robots, but how do they interact and work together and apart to yield the maximum benefit? As space destinations and objectives become more complex and dangerous, it makes good sense to use the Moon to learn how to properly conduct the serious business of exploration. Humans yearn to explore. By doing so, they acquire strategic knowledge that increases our odds for survival. Making new discoveries broadens the imagination and allows us to envision solutions to problems that might otherwise not have occurred to us. Practical experience on the Moon will serve us well as we begin humanity’s movement into the universe.

  10

  Where Do We Go From Here?

  Many of us working in or with NASA recognized that the 2004 Vision for Space Exploration (VSE) was a conceptual breakthrough. The goal of using off-planet resources to enable new capabilities in spaceflight was the fulcrum we needed to change our approach and direction to spaceflight. Making this change would open the door to a wide variety of previously unobtainable mission concepts and ideas.

  In this book, I have shared my perspective on why and how the VSE was conceived, executed, and eventually terminated—a cautionary tale, if you will, but I hope an instructive one. Lessons drawn from this history can keep us from repeating similar mistakes and help us create a better American space program, one that moves humanity into the solar system by creating new opportunities and expanding, rather than consuming, wealth.

  Because NASA’s response to the VSE was to focus on the first human mission to Mars, they devised an Apollo-style architecture, reverting to the only successful operational template for planetary exploration with which the agency was familiar. This decision effectively derailed the incremental and sustainable approach for the extension of human reach into space, intended by the VSE. An Apollo-style mission to Mars remains a bridge too far fiscally, technically, and politically. The interpretation of a human Mars mission as the central goal for the agency ignored the considered work of the VSE architects and those of us who had worked with NASA in the immediate years following its announcement. Certainly I was not interested in participating in a new “Mission to Mars” paper study that was doomed to failure from the beginning. Many of us had already experienced this during the years of the Space Exploration Initiative (1989–92), an earlier attempt to re-create the Apollo zeitgeist.

  The excitement that many of us felt at the beginning of the VSE came from the belief that those lessons about what did not work had been well learned and that a long-overdue change in the template of spaceflight was upon us. We soon became disabused of such a notion. Although many in the space community understood both the possibilities and the pitfalls of the new effort, the dominant culture in both the agency and industry was wedded (and remains wedded) to the old template. As NASA reverted to their comfort zone, both the impression and the reality that this was about “repeating” our previous experience with the Moon—to regain the glory of Apollo—was cemented in many minds. This mindless
calculus branded the lunar segment of the VSE with a “been there, done that” label, leading to the inevitable characterization that the Moon was both old hat and an unaffordable distraction.

  Given that NASA was handed a new and challenging mission to go to the Moon on two previous occasions, the SEI in 1989 and the VSE in 2004—and both times they dropped the ball on implementing it—one might imagine that a new entity is needed to conduct human spaceflight for the federal government. This concept has not gone unvoiced by the community; no less an authority than Harrison “Jack” Schmitt, Apollo 17 astronaut and the first (and for now, the last) scientist to explore the Moon, has proposed that NASA be abolished and that a new agency be established to implement a long-range, strategic plan for human spaceflight.1 Schmitt would reassign some NASA activities (aeronautics research, astronomy) to other agencies and retain within the new entity only the field centers critical to human spaceflight. The new space agency would take over existing infrastructure for these functions and maintain a minimal headquarters presence in Washington to preside over policy decisions.