The Value of the Moon

by Paul D. Spudis

  Despite the positive indications acquired from the Clementine and LP missions and subsequent studies of the presence of water ice and near-permanent sunlight near the poles of the Moon, NASA had no interest in conducting any follow-up investigations. Although these discoveries would permit long duration stays on the Moon and possible resources for additional spaceflight options, the lunar community could not get the funding to even study new missions that would have cost a small fraction of the JPL Mars program budget. Clearly, a policy decision had been made at some level that no large-scale human exploration program beyond LEO was possible: NASA’s robotic exploration budget was to be sequestered over the next couple of decades for various Mars missions. This policy was never formally written down, but as they say, money talks. Predominant in every submitted NASA budget for robotic science during the Clinton years were “green” spacecraft for Missions to Planet Earth and Mars orbiters and rovers. The former were the pet project of Vice President Al Gore, while the latter was the implementation of the wish lists of Dan Goldin, Carl Sagan, the Jet Propulsion Laboratory, and likeminded members of the Sagan-founded Planetary Society.

  However, the Mars exploration program started running into some serious technical problems. After the renowned Pathfinder mission in 1997, the first successful mission to Mars since Viking two decades before, the next two Mars missions failed. The Mars Climate Orbiter, a 1999 mission designed to characterize atmospheric phenomena and look for possible clues to the record and mechanisms of climate change on the planet, missed its orbital insertion and was lost. Post-mission analysis traced this failure to the use of English units of measurement in a command stream that required metric units. Appropriate derision of JPL and agency competence followed this jaw-dropping revelation. Next, the Mars Polar Lander stopped transmitting shortly before its entry into the martian atmosphere; the inference is that it had crashed on the martian surface. Serious soul-searching at the agency followed these failures, but only about the means, not about the ends. One great concern was with Goldin’s alleged devotion to FBC (although it is hard to ascribe both of these lost missions to this paradigm, since their combined cost was over $300 million in FY1999 dollars) and not with the idea of a continuing series of Mars missions designed to follow the water. Following these failures, the revamping of the program now assured that the means of future missions to the red planet would each cost an appropriately staggering amount of money, all in pursuit of the elusive ends: water and therefore possibly past life.

  The Human Space Program

  Human spaceflight efforts following the demise of President George H. W. Bush’s Space Exploration Initiative (SEI) in 1992 included the continuation of the space shuttle program, with its wide variety of satellite deliveries and life science experiments, as well as servicing missions to the Hubble Space Telescope. The goal of building a permanently occupied human space station had not been abandoned, but it had been reimagined. Space station Freedom, initially proposed by President Ronald Reagan in 1984, went through several design iterations, changes that delayed the start of its construction and increased the cost of the program. Despite program review after the Challenger accident and the grounding of the shuttle fleet by hydrogen leaks, NASA pressed on with station design and redesign. The fits and starts of the program led to exasperation in Congress, where it survived a 1993 vote in the House of Representatives by a margin of one. The human spaceflight program had reached a crisis of both confidence and capability.

  Despite the decline and termination of the SEI, debate continued over the future direction of human spaceflight, as outlined by the Paine, Ride, and Augustine 1990 reports. At this time, one of the biggest concerns of science and technology policy was the problem of nonproliferation. The Soviet Union had dissolved, and there were concerns in the West that Russian scientists might sell their services and capabilities to rogue nations to make the infamous “weapons of mass destruction” and cause the spread of nuclear capabilities. It was thought by some that a joint space project involving both the United States and Russia in collaboration would keep the Russian military industrial complex safely occupied and under the scrutiny of its Western partner nations. The Soviets had built a fairly large and capable space station in the 1980s called Mir. Soviet cosmonauts conducted routine, extended stays on Mir, arriving and returning on their Soyuz spacecraft. Announced in 1993, the logical, initial starting point for this new East-West spirit of cooperation, called Shuttle-Mir, had rotating crews taking the space shuttle to Mir, where crews would live together, showing that we could work together peacefully in space.9

  Between 1995 and 1998, there were eleven shuttle missions to Mir, where American astronauts spent close to a thousand days in orbit aboard the Russian space station. Joint operational and flight techniques were developed between the two countries. Despite some shaky moments (including a fire onboard the station requiring quick and decisive action by the crew), both parties considered this cooperative flight experience successful, leading to the final redesign of the U.S. space station as a new International Space Station (ISS).10 This new design would be based on some key components provided by Russia. The Zarya (Functional Cargo Block), launched in 1998, and the Zvezda habitat and laboratory, launched in 2000, would become the nucleus of the new modular space station. Over the course of the next decade, twenty-seven shuttle flights and six Russian Proton and Soyuz flights would be needed to assemble the ISS in orbit. Starting in 2001, the ISS has been continuously occupied by crew, including during the period of the thirty months that the shuttle was grounded after the Columbia accident of 2003. With the delivery and attachment of the Alpha Magnetic Spectrometer, assembly of the ISS was finally completed in May 2011.

  In the early years of the new millennium, as assembly of the ISS finally began, some in the agency considered the possible next steps for humans in space. Despite the failure of the SEI and the ongoing difficulties of the robotic Mars program, the obsession with human Mars missions was firmly entrenched within NASA. Most of the agency’s advanced planning people spent their time devising new architectures designed to achieve that elusive goal. A core group of engineers in the Exploration Program Office at the Johnson Space Center continued to evaluate the requirements and difficulties of a human Mars mission, as well as alternative concepts involving return to the Moon. The post-SEI analysis of the Houston engineers had determined that with the launch of a few large expendable rockets and a couple of shuttle flights, we could return humans to the Moon.11 Their analysis showed that the massive infrastructure creation outlined in the 90-Day Study was not strictly necessary, at least for the initial steps of human lunar return, especially if lunar resources (oxygen) were incorporated into the architecture. Such a mission would have limited stay time and capability, but at least it established a foothold on the lunar surface and could become a point from which the possibilities of extended presence could be investigated.

  Studies of these architectures and plans continued, including investigations of missions to destinations other than the Moon. An early study mission favorite of NASA was the Lagrangian-point (L-point) mission, a human mission to one of the gravitational balance points in the Earth-Moon system, a point at which Earth and Moon appear to be stationary in the sky. The problem with L-point missions is that there is nothing there, except for what we put there. In the future, L-points could become critically important as staging areas for missions to the planets, or to collect exported material such as water launched from Earth or from the Moon. Although there was some interest in human missions to near-Earth asteroids, they were thought to be of much less importance, something to be reconsidered in the future. At the time, little was known about most of these objects, and asteroids had most of the disadvantages of a Mars mission (months of travel time, poor abort capability, and so on) with few of the benefits—for instance, most of these objects are simple, relatively homogeneous rocks, offering little in the way of exploratory variety.

  As study of human Mars mission ar
chitectures continued, two things became increasingly clear. First, several technical developments, some of significant magnitude, were needed before human missions to the planet were feasible. Some of these involved “known unknowns,” things we know that we need but don’t yet have, like nuclear rocket propulsion or a solution to the dreaded entry, descent, and landing (EDL) problem,12 while others consisted of the “unknown unknowns,” problems of mission design or requirements that we don’t even know about, let alone have any idea how to solve. Given the state of our knowledge, these studies showed that a human Mars mission is not possible in the near future. Moreover, even at favorable opportunities, a Mars mission requires between one and two million pounds to low Earth orbit, most of which is propellant. It was estimated that to assemble in orbit a Mars spacecraft able to conduct a single human mission would require between eight and ten launches of a Saturn V-class heavy lift launch vehicle. The entire manned Apollo mission series of 1968–72 launched ten Saturn V rockets. This means that a single human Mars mission would cost several tens of billions of dollars, even if such a heavy lift vehicle existed. Other, more innovative approaches would have to be considered.

  A key step toward understanding how to conduct a human interplanetary mission came in 1990 when Robert Zubrin, an engineer from Martin-Marietta, published his Mars Direct architecture.13 Although this plan bypassed the Moon, its significance for lunar exploration derives from its reliance on in situ resource utilization (ISRU). By manufacturing propellant on Mars for Earth-return—processing the carbon dioxide (CO2) in the martian atmosphere into methane (CH4) for propellant for the return trip—significant mass savings are realized, thus greatly reducing the initial mass required in LEO. In addition, the Mars Direct architecture separated cargo and crew. A nuclear power plant and the processing equipment needed to make methane propellant from the atmosphere would be delivered to the martian surface two years before the crew arrived. This approach introduced a safety factor, in that, if the atmosphere processing was less efficacious than believed, the crew would not be trapped on the surface of Mars without the fuel to get home because they would launch from Earth only after the return trip fuel had already been manufactured and stored on Mars. Despite these benefits, engineers from both NASA and the aerospace industry were slow to accept even the minimal risk introduced by the ISRU scheme proposed by Mars Direct. This ingrained resistance to ISRU carried over to architectures for lunar return as well.

  Despite the innovative nature of some ideas in Mars Direct, a human Mars mission was still too high a fiscal and programmatic cliff to scale. Thus, for most of the 1990s, despite the presence of the alleged fossil forms in ALH84001 and Goldin’s lobbying, the Mars program remained a series of scientific robotic probes “following the water” while consuming more and more of the planetary exploration budget.

  The Loss of Shuttle Columbia and Its Aftermath

  In the years after Lunar Prospector, but before the Vision for Space Exploration (ca. 1998–2004), several attempts were made to restart lunar exploration, at least in terms of a series of robotic flights to address some of the new and exciting findings and unknowns about the poles. The vociferous debate over the presence and extent of polar ice continued and it was clear that more and higher quality data were needed to resolve the issue of water ice. Earth-based radio telescopes were barely able to see into parts of the permanently shadowed polar areas of the Moon. Both the eighty-meter Deep Space Network Goldstone and the huge, three-hundred-meter Arecibo radio dish mapped the south pole of the Moon, looking for evidence for the presence of ice. The data were inconclusive, since diffuse backscatter obtained solely from zero phase (monostatic) radar, in which the same antenna sends and receives the pulses, cannot uniquely distinguish between rock and ice. The bistatic technique, where the receiving antenna is different and separated by a known distance from the transmitter, can uniquely determine this, providing evidence that caused numerous scientists to support the interpretation that ice had been detected.14 As a believer in the polar ice hypothesis, I can attest to our desire to obtain new, high quality data from an orbiting radar experiment. The problem was finding a ride to the Moon. Japan has long harbored lunar dreams and had prepared a most ambitious orbiting mission, SELENE (later renamed Kaguya), a spacecraft the size of a school bus with a payload of almost every remote sensing instrument known to us.15 But SELENE kept getting delayed, then was grounded by a launch vehicle failure and a Japanese economy in recession. Europe kept studying lunar missions, including both orbiters and a south polar lander, but each time such a flight was proposed, it was deferred. After downsizing their lunar mission into a small, technology demonstration, Europe’s SMART-1 orbiter finally launched in late 2003, taking over a year to spiral out to the Moon using solar electric propulsion. The SMART-1 mission had limited instrumentation but it contributed to our knowledge of the poles by improving our mapping coverage and extending observation of polar lighting over a longer season.

  A project sponsored by the Defense Advanced Research Projects Agency (DARPA) in 2003 looked at the possible impact of using lunar material resources to create new capabilities in space. This effort was mostly a paper study, although its authors hoped to parlay that report into a series of small robotic missions designed to follow up on the polar discoveries. I was working at the Johns Hopkins University Applied Physics Laboratory (APL), a university-based research organization similar to NASA JPL, when they studied that effort. We outlined concepts for a fleet of small satellites, each less than 100 kilograms, that could be operated in tandem to create high-resolution data on lunar polar environments and materials. Such a mission series would yield definitive answers for some polar questions, allowing us to understand if developing lunar water was feasible and what leverage in spacefaring capabilities it would yield. Although this topic is potentially the kind of transforming, “far out” idea DARPA claims to seek, the study was not approved to the next level of development, dashing the hopes of lunar enthusiasts yet again.

  Despite its deferment, several positive results came from this effort. We understood how to configure a small mission that could get high quality data for the poles. A parametric study by a group at the Colorado School of Mines led by Mike Duke, former lunar sample curator and one of the masterminds of the 1980s lunar base movement, led us to understand the break points for lunar mining.16 For example, what concentration levels of water make the effort of lunar mining economically worthwhile? It turns out that water concentrations of at least 1 weight percent are needed to balance the estimated costs of extraction, including the transportation system. Fortunately, we already knew that the existence of such quantities was likely: LP hydrogen data indicated an average concentration of 1.5 weight percent for the entire polar region, suggesting the possibility of even larger amounts of water in the shadowed areas.

  On February 1, 2003, the space shuttle Columbia broke apart during reentry.17 All seven crewmembers were killed. Until the cause of the accident could be determined and a fix applied, the shuttle would remain grounded. As with the loss of Challenger, the previous shuttle disaster in 1986, this accident once again focused the nation’s attention on the meaning and purpose of our national human spaceflight program. But this time, it did more than that. Sean O’Keefe, the new NASA administrator who had succeeded Dan Goldin in 2001, had a reputation as a “green-eyeshade” guy. He had been recruited to solve the agency’s considerable budgetary and accounting problems with the International Space Station project, which he did during his tenure of office. Profoundly shaken by the shuttle accident, O’Keefe decided that if humans were going to continue to risk their lives by going into space, there must be some great and meaningful purpose of national import to the trip.18 O’Keefe was determined to find it.

  As most attention was directed to the Columbia accident investigation, a simultaneous and largely unnoticed parallel effort was undertaken to review the purpose and objectives of human spaceflight.19 It was recognized that future budgets for the
civil space program were likely to be tightly constrained, so any possible plans must be constructed for an austere fiscal environment. Given these limitations, was there a way to revitalize the human spaceflight program, or had we reached the end of the trail?

  Among those considering the next steps during this interruption in the human spaceflight program was Klaus Heiss, an economist who had conducted some of the early feasibility studies of the shuttle. He became convinced that a return to the Moon with the aim of learning how to establish permanence through the use of local resources could be achieved under current budgets, laying the groundwork for later, more ambitious space efforts. A friend of the Bush family, Klaus went directly to see the president with his idea, who passed it on to NASA for detailed technical study. At Headquarters, Associate Administrator for Human Spaceflight Bill Readdy and members his team undertook a feasibility study of Heiss’s plan for the establishment of a base on the Moon.20 The group continued to work on the problem of a return to the Moon for the next year and a half, coming up with an approach that was both affordable and technically robust.21 This “Gold Team” undertook an examination of the problem of trans-LEO human spaceflight, independent of previous advanced study work.