The Lunar Anthropic Principle

One of the most remarkable books of the last 30 years is The Anthropic Cosmological Principle by John Barrow and Frank Tipler. The “principle” is really nothing more than a statement that the laws governing how the universe operates seem to be arranged so as to require our existence and participation. In other words, the human race is not some accidental byproduct of creation, but an essential component of the way the universe is put together. This philosophical gem came up recently during a wide-ranging discussion of ideas at a post-lecture dinner with media/journalism honors students and their advisors at the University of Texas at Tyler. Though we discussed many things, the anthropic principle came up during questions regarding lunar development. And as good conversation always does, it made me think deeper.

I hadn’t previously connected the Barrow-Tipler principle with a quote (in the same vein) that I use in my lunar development talks. This quote comes from Krafft Ehricke, a member of Wernher von Braun’s original rocket design team from Peenemunde. Ehricke spent a lifetime thinking about the broader, philosophical aspects of space travel and the colonization of other worlds. Ehricke remarked in 1984 that, “If God wanted man to become a spacefaring species, He would have given man a Moon.” Ehricke’s quote distills down to its essence the truth about the Moon’s utility—its singular value in developing new spaceflight capabilities and our ability to travel throughout space. I’m tempted to call Ehricke’s statement “the lunar anthropic principle.”

I’ve detailed in previous writings the Moon’s value. The Moon’s proximity to Earth and its material and energy resources make possible the construction of a permanent spaceflight transportation infrastructure, thereby giving us the means to live and work on another world for extended periods of time. Because the Moon is close (in orbit around the Earth, 400,000 km away) we can travel to and from the Moon at will—launch windows are continuously open. There is no other extraterrestrial body for which this is true.

Our closeness to the Moon (three-second round-trip light travel time) also permits near-real-time control from Earth of machines located on the lunar surface—an amazing advantage in that much of the hard, repetitive or difficult work on the Moon can be accomplished using teleoperated robots. This capability positions humans for more creative pursuits, such as surface exploration, while limiting our exposure to harsh environments, as we build up our knowledge about our new surroundings—valuable information for those planning to venture further out into space.

The Moon’s resources come in two forms: energy and materials. The energy actually comes from the Sun—the Moon provides a place on its surface to collect solar photons nearly continuously. This illumination can be converted into electrical power via solar arrays. The poles offer multiple locations where the Sun can be seen for more than 80-90 percent of the year. The periods of darkness are short, from a few hours to a few tens of hours. We can bridge these dark periods with fuel cells that combine hydrogen and oxygen to generate electrical power, producing water as a byproduct. When the Sun is visible, the power generated by solar arrays can be used to crack stored water into its component hydrogen and oxygen gases. Thus, water becomes a medium of energy storage and permits the continuous generation of power, an essential condition for human habitation and productive work off the Earth.

Fortunately, the other side of the resource coin offers us the feedstock for this power system. The latest round of robotic spacecraft mapping the Moon have found significant quantities of water ice at both poles. The exact amounts and physical state of this water is still uncertain (we need to send robotic landers down to the surface to characterize the deposits in detail), but there is no doubt that the quantities of water present are significant, as much as 10 billion tons of water at each pole.

Thus, there are two areas of the Moon where resources (water and sun) are placed side-by-side: the poles, where the Moon’s axial tilt creates just the right conditions for light (solar energy) and darkness (water ice-traps). Before humans return to the Moon, we must send numerous small robotic probes to the poles to map and survey potential prospects. Such strategic knowledge is critical to selecting the optimum site for a permanent outpost.

Considering all of these fortunate coincidences, Ehricke’s conjecture is not far off the mark. No other space destination brings together such enabling proximity and utility as does the Moon. So why is the idea of resource utilization on the Moon still met with resistance by some? Over my long career in lunar studies, I’ve learned that part of this resistance comes from the reluctance of some engineers to consider the use of extraterrestrial materials. We have used solar energy on spacecraft for almost 60 years—it is a proven and well-founded technology. Extracting materials from space-based sources and forming them into useful spaced-based products is another matter. Since this has never been done, it carries with it the undeserved suspicion of being excessively risky. In truth, processing lunar material requires technology no more advanced than 19th-century industrial chemistry. Melt the ice, fractionally distill it to remove impurities, crack it into its component hydrogen and oxygen, then cryogenically freeze those gases for use as rocket propellant.

The Moon is ideally placed and provisioned to provide us what we need to build a permanent transportation and habitation system in space. In that sense, it is a form of the anthropic principle, and it requires human ingenuity to take advantage of what the Moon has to offer. It is a body ideally placed for our use and benefit—a “stepping stone,” if you prefer to see it that way. Of course, all this is enabled by our ability to perceive and decipher the physical laws that make spaceflight possible, again circling back to the original cosmological anthropic principle—that how the universe operates seems to be arranged so as to require our existence and participation.

The ability to simply fly into space and back is somewhat miraculous in itself. What Don Pettit explains as the “Tyranny of the Rocket Equation,” describes how getting into orbit is not only extremely difficult, but barely possible—as most of the mass of a rocket is propellant (what he identifies as “dumb mass”), leaving only a small fraction (usually less than 10 percent) available for the deliverable (“smart mass”) payload. In fact, as Pettit explains, if the radius of the Earth were 50 percent greater, spaceflight would not be possible—there is simply not enough energy in the chemical bonds of known propellants to get a payload to orbit. Again, it appears that our universe is constructed in a way that allows us to venture off the planet, but only “just”—and even then, only with great difficulty.

We can break the Tyranny of the Rocket Equation once we learn how to use what we find in space—first on the Moon, using lunar resources to provision and fuel spacecraft and habitation systems. By utilizing the Moon and its assets over time, flights between Earth and Moon, and all points in between, will become affordable, profitable and routine. Through the development of this new system, we will finally move from an Earth-based to a space-based operational template, one holding huge economic and national security benefits. It’s as if the Moon was created for our use and benefit. To ignore its value and importance to our future would be extremely shortsighted.

Paul D. Spudis | READ MORE

Paul D. Spudis (1952-2018) was a senior staff scientist at the Lunar and Planetary Institute in Houston, Texas, and a prolific author on the subject of the moon. His books include The Value of the Moon: How to Explore, Live, and Prosper in Space Using the Moon's Resources.