These remarks were given by John Marburger on March 15, 2006 during the Keynote Address of the 44th Robert H. Goddard Memorial Symposium in Greenbelt, Maryland.
The topicof this year's symposium, "Engineers, Scientists and the Vision," reflects thecombination of mental attitudes needed to accomplish great things in space, andI am pleased to add a few thoughts of my own this morning on these topics.
I am alwayspuzzled by debates over the Vision for Space Exploration because the choicesare so constrained by physical reality. We humans dwell in a vast universewhose chief features only became apparent during the 20th century. We haveknown for a long time that a huge gap separates the objects trapped by thegravity of our star, the Sun, and everything else. Information about phenomenabeyond that gap can come to us only through the rain of photons and otherelementary particles spewed out by the awesome processes of the cosmos. Ourobservations of that part of space began in prehistoric times and they continueto sustain the growth of science in our era. Phenomena on our side of theinterstellar gap, in what we call the solar system, are potentially amenable todirect investigation and manipulation through physical contact, and canreasonably be described as falling within humanity's economic sphere ofinfluence.
As I see it, questions about the vision boil down to whether we wantto incorporate the solar system in our economic sphere, or not. Our nationalpolicy, declared by President [George W.] Bush and endorsed by Congress lastDecember in the NASA authorization act, affirms that, "The fundamental goal ofthis vision is to advance U.S. scientific, security, and economic intereststhrough a robust space exploration program." So at least for now the questionhas been decided in the affirmative.
The wordingof this policy phrase is significant. It subordinates space exploration to theprimary goals of scientific, security and economic interests. Stated this way,the "fundamental goal" identifies the benefits against which the costs ofexploration can be weighed. This is extremely important for policy-makingbecause science, security and economic dimensions are shared by other federallyfunded activities. By linking costs to these common benefits it becomespossible, at least in principle, to weigh investments in space explorationagainst competing opportunities to achieve benefits of the same type.
I want tostress how very different this kind of thinking is from the arguments thatmotivated America's first great space vision, the Apollo program. President[John F.] Kennedy launched the Apollo program during an intense period in theCold War, four years after the Soviets launched the first Sputnik satellite. Inhis 1961 message to Congress, Kennedy said of sending a man to the Moon andreturning him safely that, "No single space project in this period will be moreimpressive to mankind, or more important in the long-range exploration ofspace; and none will be so difficult or expensive to accomplish. ..."
The tone ofthis message clearly conveys the intention to send a signal to the world that America will lead the way into space, and this spirit remains a vital factor in our abilityto accomplish great feats of engineering to get us there. The Apollo programwas what mathematicians call an "existence proof" -- a demonstration that aproblem does have a solution and that efforts to discover its details will notbe in vain. Like all firsts, it was unique. No subsequent space endeavor can bequite like it.
PresidentBush's vision also declares the will to lead in space, but it renders theultimate goal more explicit. And that goal is even grander. The ultimate goalis not to impress others, or merely to explore our planetary system, but to useaccessible space for the benefit of humankind. It is a goal that is notconfined to a decade or a century. Nor is it confined to a single nearbydestination, or to a fleeting dash to plant a flag. The idea is to beginpreparing now for a future in which the material trapped in the Sun's vicinityis available for incorporation into our way of life.
Given theexpense of climbing out of Earth's gravity well, the natural course of spacedevelopment begins with objects trapped in Earth orbit, including the Moon,followed by objects trapped in solar orbits near the Earth's, and thenextending opportunistically to other destinations.
The firststage of exploiting cislunar space is already well advanced, partly becauseapplications have been found that can be achieved with small payloads and yetwhose value to society exceeds the cost of launch. It is likely that thesenear-Earth applications will always dominate the use of space because Earth iswhere the people are, as well as the environment that sustains them. We mustnever forget that within our solar system the object most important forhumankind is Earth, and Earth-oriented space applications merit priority in abalanced portfolio of public investment.
The Moonhas unique significance for all space applications for a reason that to myamazement is hardly ever discussed in popular accounts of space policy. TheMoon is the closest source of material that lies far up Earth's gravity well.Anything that can be made from lunar material at costs comparable to Earthmanufacture has an enormous overall cost advantage compared with objects liftedfrom Earth's surface. The greatest value of the Moon lies neither in sciencenor in exploration, but in its material. And I am not talking about mininghelium-3 as fusion reactor fuel. I doubt that will ever be economicallyfeasible. I am talking about the possibility of extracting elements andminerals that can be processed into fuel or massive components of spaceapparatus. The production of oxygen in particular, the major component (bymass) of chemical rocket fuel, is potentially an important lunar industry.
What arethe preconditions for such an industry? That, it seems to me, must be a primaryconsideration of the long-range planning for the lunar agenda. Science studiesprovide the foundation for a materials-production roadmap. Clever ideas havebeen advanced for the phased construction of electrical power sources -- perhapsusing solar cells manufactured in situ from lunar soil. A not-unreasonablescenario is a phase of highly subsidized capital construction followed bymarket-driven industrial activity to provide lunar products such asoxygen-refueling services for commercially valuable Earth-orbiting apparatus.This is consistent with the space policy statement that the U.S. will "Develop the innovative technologies, knowledge and infrastructures both toexplore and to support decisions about the destinations for human exploration."
I watchedthe live video coverage of Neil Armstrong taking the first footsteps on theMoon, and I was tremendously excited by it. To actually do something productiveon the Moon would validate and justify the risk and expense of those earlyventures and create an entirely new level of excitement. The operations I havedescribed are intricate but many could be accomplished robotically. It isdifficult for me to imagine, however, that such a complex activity could besustained without human supervision and maintenance. This, in my view, is theprimary reason for developing the capacity for human spaceflight to the Moon.It is a pragmatic reason and more likely to be sustainable over the decadesnecessary for success than curiosity or even national prestige.
Where doesMars fit into this picture? At the present time, much commentary to thecontrary, we do not know how to send humans to Mars and return them safelywithin a reasonable cost envelope. The whole point of the vision, however, isto make the solar system accessible, and Mars and the asteroids whose orbitspenetrate Mars orbit are the nearest objects suitable for development beyondthe Moon (I am excepting Venus for its high-surface temperature). The currentvision policy document says the U.S. will "[e]xtend human presence across thesolar system, starting with a human return to the Moon by the year 2020, inpreparation for human exploration of Mars and other destinations." It does notpropose a date for a human Mars mission. The cost and safety of a human Marsmission are very scenario-dependent, and I hesitate to say anything more aboutit.
There is noquestion, however, that the expense of such a mission would be vastly reducedif the bulk of its fuel and massive components could be obtained from materials,and manufactured, outside Earth orbit. The Moon is a logical place to do this.As to the motivation for a human expedition to Mars, there is an obviousprestige value for a nation that leads the first human-to-Mars mission. A morepragmatic objective is to establish on Mars the same kind of industrialinfrastructure that I described for the Moon. What makes the Moon operationeconomically viable are the Earth-oriented markets. That is not likely to bethe case for a similar operation on Mars unless economically attractivematerials are found on Mars itself, or among the asteroids. Consequently, aMars operation complex enough to warrant human oversight will have to be fullysubsidized by governments during a long period of robotic exploration beyond Marsorbit.
It shouldbe obvious from these remarks that I believe the vision President Bush setforth on January 14, 2004, is not one for a few decades, but for a much longerperiod of space development. That is why the vision emphasizes the need to"[i]mplement a sustained and affordable human and robotic program to explorethe solar system and beyond."
To besustainable, the space exploration budget must grow at the same rate as thedomestic discretionary budget. To be affordable, its fraction of that budgetmust be small enough to be stable against competition from other parts of thebudget, and in particular those that are perceived to serve a wider variety ofsocietal needs. And yet it must be large enough to carry the project forwardand sustain the necessary community of technical people. I know there areconcerns that space science may suffer by competition with the perpetuallyexpanding space exploration theme. But science is one of those primaryobjectives that space exploration is supposed to accomplish and it has muchpopular support. I believe that in the long run space-science funding willremain at levels strong enough to support a healthy program.
JohnMarburger is director of the Office of Science and Technology Policy, ExecutiveOffice of the President.
NOTE: The views of this article are theauthor's and do not reflect the policies of the National Space Society.
Visit SPACE.com/Ad AstraOnline for more news, views and scientific inquiry from the National SpaceSociety.