Commentary | Why the Moon, and How
The case for the permanent manned return to the Moon — as a destination in its own right, and as a platform for the human and robotic exploration of the solar system — is clear.
Great societies and civilizations advance in evolutionary ways as well as revolutionary ways. Positive revolutionary progress can be categorized as social and technological. Social progress advances personal freedoms and opportunities. Technological progress advances the power of the individual and groups of individuals, and potentially also personal freedoms and opportunities, although such advances can also be used to repress and intimidate.
The Moon is our closest planetary body, roughly three days’ flying time, with almost instantaneous communication with Earth. The rival Mars, while essentially as hostile to human life as the Moon, requires about a year of travel time from Earth, with a significant communications delay. A strategic view of space exploration and settlement places the Moon and Mars in their proper order based on their proximity to Earth.
While space during the Apollo program of the 1960s was purely a government-led effort supported by American industrial might, today we see the beginnings of a transition to where commercial interests are staking claims to the space economic sector beyond the needs of the government. This is evident in the emerging space tourism market, commercial launch systems that service the government and private sectors, resource recovery plans via asteroid mining and sample return from the Moon, and privately financed space-based science.
Without a doubt, governments are still the largest customers. This will change as launch costs decrease, a space/lunar infrastructure is created, space resources become more valuable, and the space/lunar environment becomes critical for certain types of manufacturing and processing.
The Moon, far from being a barren wasteland, has a regolith composed of many of the elements needed to build an infrastructure for human activity. Hydrogen, oxygen, silicon, magnesium and, it is strongly believed, water in ice form are found in the lunar regolith. Solar power can be viable on the Moon with its two weeks of daylight per month, and the solar panels could be manufactured on site using local resource silicon. Ideas for vast solar farms embedded on the surface of the Moon have been suggested. Significant quantities of helium-3 can be tapped as nonradioactive nuclear fusion reactors become feasible as a source of power.
With the current revolution in 3-D manufacturing technologies, we can envision sending robots to the Moon, in advance of people, where they would begin to build fully functional structures for habitation and begin to mine the regolith for the above-mentioned elements. Even today such advanced manufacturing can create objects of significant complexity using multiple materials. In-situ resource utilization coupled with advanced robotic manufacturing capabilities implies that our lunar facilities will be almost autonomous with full self-repair capabilities.
The challenges and risks are significant, however. There are gaps in our knowledge of how to keep humans alive and robust in the space environment in general and on the Moon in particular. Engineering reliable hardware and software for long lives in the harsh space and lunar environments also requires the solution of a number of difficult technological problems.
But we need to keep in mind that the health and engineering issues on the day President John F. Kennedy gave his speech challenging the United States to send man to the Moon before the end of his decade were even more difficult than those we face. We did not know what many of the problems were, much less how to solve them. We had the faith, though, that with a sizable, sustained effort we would be able to match the challenges. And we did.
What did we get in return? We landed men on the Moon. On a political level, the nation demonstrated its engineering and scientific superpower status. To paraphrase Kennedy, the United States was able to marshal tremendous intellectual and material resources in a short period of time to solve a problem that only a few years before was deemed beyond humanity’s reach. The space race born of the Cold War gave birth to a very long list of technologies resulting in numerous industries that gave impetus to our economy, from which we benefit to this day. Included in this bounty are the medical sciences and technologies that we depend on, as well as the rarely mentioned ability to manage super-large projects of tremendous intricacies and logistical challenges.
What do we need in order to return people to the Moon with an eye toward permanence? We need to be able to send mass to the Moon, of course, but the strategic vision requires us to very quickly be able to use local lunar resources to cover most of our needs. In-situ resource utilization will allow us to use lunar materials to build structures, manufacture very large solar panels for energy, and extract valuable elements from the lunar regolith that can be used to create an industrial infrastructure. This and advanced manufacturing techniques, also known as 3-D printing technologies, are the keys to a viable manned exploration and settlement effort.
In order to advance the mission outlined above we will need the following: access to orbit; low Earth orbital operations; human-rated transportation to the Moon along with all the technologies for descent and landing on the Moon; lunar habitats; solar, battery and nuclear power systems; life-support and shielding systems to safeguard against radiation, micrometeorites, and zero and one-sixth gravity; the ability to perform surface missions; in-situ resource utilization in conjunction with necessary logistics and technologies; and fuel to ascend into lunar orbit with a return to Earth. We need to be able to ameliorate the adverse psychological effects of close quarters and isolation from Earth and family. Supporting human life requires a number of additional basic capabilities — in particular, plant growth in a closed and reduced gravity environment, waste processing and nutrient recovery, atmosphere revitalization and water management. Engineering challenges include propulsion, power, structures, optics, instrumentation, environmental controls, guidance and control, data management and storage, and communications.
These are all difficult challenges. Research and development will solve these problems and as a bonus lead to tremendous advances in engineering and medical sciences and technologies. It is not possible to predict all of these spinoffs to the Earth economies. But the history of Apollo, which contributed to the advancement of many sectors of the U.S. economy and gave birth to many more, gives us reasonable credibility when we say that we expect many advances that will feed into the Earth economy.
Clearly, the human settlement of the Moon implies the support of robots and automated systems. Research is progressing very fast in these disciplines, but even the most advanced robots today cannot autonomously explore and build on the Moon. They require human guidance and participation.
A lunar base will first be an engineering and medical laboratory for the study of extraterrestrial infrastructure development, and for the creation of a safe environment for human habitation. Access to lunar resources will drive industrial activity. Public interest in space travel will also develop as it has today for tours of low Earth orbit.
Second, it will be a site for the scientific study of the Moon and the solar system.
In conjunction with these, the Moon will become an economic nodal point that will support space transportation in cislunar space, and outward to Mars and the asteroids and outer planets.
Resources recovered on the Moon will be used to support the manufacture of items needed locally as well as of use beyond the Moon.
Culturally, humans will evolve in other ways as well. Some predict that in a matter of a few generations, the human species will bifurcate as a result of the change to the lunar environment.
We can be certain that there is no turning back from spacefaring, and the positive feedback to life on Earth.
Haym Benaroya is a professor of mechanical and aerospace engineering at Rutgers University.