The Moon is the key resource needed to open up the frontier of space

Last fall, after much anticipation, the Augustine Committee presented us with their assessment of the future of space exploration.  Its basic conclusion was that at currently envisioned budgets, the Program of Record (a.k.a. ESAS, Project Constellation) would not get us back to the Moon before many decades had passed, if then.  This meme has been picked up by many in the space community to the point where is it now cliché to claim that we don’t have enough money to do anything in space.  Hence, the direction proposed in the new budget takes NASA out of the space transportation business entirely, freeing up their budget to focus on technology development, and contracting with commercial providers to create access to low Earth orbit (LEO) and the International Space Station (ISS).

How are costs estimated for space systems?  The costing exercise for the Augustine Committee was done by The Aerospace Corporation, a non-profit science and engineering company run for the U.S. Air Force.  Their costing procedures (described briefly on page 82 of the committee report) includes estimating the time and level of effort it takes to develop a system, informed by data from past projects.  The vast bulk of this costing effort deals with launch vehicles and systems.

Looking over cost estimates is a strange experience.  Almost anyone can immediately see inflated levels of costing for things they know about, but are uncertain for other items.  Bob Zubrin wrote a stinging rejection of the Aerospace Corporation’s costing just before the Augustine Committee released their report.  He noted in particular that the estimates included several years of increasing ground operations costs, even while nothing was being launched.  Of course, if you pull together a ground crew, you have to pay them to keep them around, even during slack times.  But his point is a good one; why should it cost more than Shuttle does now to support a launch system that requires an order of magnitude less preparation than the highly complex Shuttle Orbiter?

Using these estimates of the cost of the existing architecture, the Augustine Committee concluded that it was unaffordable.  What did they do then?  Rather than fix the problems with the ESAS architecture, they discarded the entire Vision for Space Exploration and came up with the so-called “Flexible Path” (FP).  Although cloaked in platitudes about how technology development will give us options to go to many destinations beyond LEO, the real motivation for this idea is revealed by the committee’s words on “public engagement” (e.g., “It (FP) would provide the public and other stakeholders with a series of interesting “firsts” to keep them engaged and supportive.” – Augustine report, p. 15).  Thus, the goal of FP is to create Apollo-like spectacles for public consumption, rather than creating steps toward increased space faring capability.

We can wait and hope for the proposed technology development program to provide us with magic beans, or we can begin that process now by returning to the Moon with robots and humans to learn how to harvest and use its material and energy resources.  Creating a sustainable system of space faring that can take us anywhere we want to go would be a real accomplishment.  By gaining this knowledge and expertise, mankind will be free to choose many space goals, thereby achieving “at will” space destination capability.

Jeff Greason, President and co-founder of XCOR Aerospace and a member of the Augustine Committee, recently spoke at the annual Goddard Memorial Symposium.  He asserted that for the near future, we have no path to move people beyond low Earth orbit because the options the Augustine Committee looked at cost more than the United States can afford or is willing to spend.  His principal message to Symposium attendees was to “deal with it.”

According to the Augustine Committee, “The cost of exploration is dominated by the costs of launch to low-Earth orbit and of in-space systems.”  This outlook is one reason why so much of the costing focus was on building Ares V, the super-heavy lift (188 mT) launcher designed for human Mars missions.  For such a mission with chemical propulsion (the only technology currently available) you need about one million pounds in LEO, of which more than 70% is propellant.  Going to Mars is expensive because you must lift all of that fuel out of the deep gravity well of Earth.  Even with the economies of scale provided by a super heavy lift rocket, it still costs tens of billions of dollars to mount such a mission.

Making propellant on the Moon completely changes these numbers, yet use of lunar resources is discussed in only a few brief paragraphs of the Augustine report.  We now know (as the committee did then) that water is present at the lunar poles in significant quantity and that its use to make rocket propellant can create a transportation system that could routinely access all of cislunar space.  This should be the objective of lunar return: to create a space “transcontinental railroad” through the use of lunar resources.  Once established, we can go to the planets with relative ease.

Is any of this possible under the existing budget?  Not if we dissipate our money with pointless and unfocused technology development.  Of the many advantages of the Moon, one of the biggest is that it is close enough that preliminary work can be done by robots on the lunar surface – controlled and remotely operated from Earth.  By emplacing robotic assets on the Moon before human arrival, we can begin to survey, process and store water for use well in advance of human arrival.  Sending robotic assets in advance of people allows us to start creating capability now, without a major increase in budget.  It simply requires a sense of clear objectives; we have the technology to work this problem now.

Simply put, our space objectives need to be – arrive, survive and thrive.  To do that, the goal must be stated, mapped out and achieved before setting out to the next destination.  A sustainable, expandable transportation system in space can be devised by using the resources we find in space.  We will learn how (and if) we can do this on our Moon.  Once we don’t have to haul everything with us from the Earth, costs become lower.  When you don’t have to use 90% of your travel budget just to get out of town, a lot more people can take the trip.  Before you know it, you have a space-based economy.

The nation has important strategic and economic interests in cislunar space and it is entirely appropriate for the federal government to develop a sustainable and extensible cislunar transportation system.  NASA needs to lead and point the way so that the private sector (not just aerospace companies) can invest in and develop the yet unknown technologies that will improve our lives here on Earth as we move out to explore and ultimately settle the new territory of space.

The Moon is a classroom, a test bed and a supply depot.  By using its resources, humanity can create the capability to live, work and travel in and beyond cislunar space.  As a nation, we cannot and must not pass on this enterprise.

Radar mosaic of the floor of the north polar crater Peary, showing many craters with elevated CPR inside, but not outside, their rims. This material is probably water ice.

Last year, India’s Chandrayaan-1 lunar orbiter spent eight months mapping the surface of the Moon.  I had the honor of being the Principal Investigator of an experiment on that mission, the Mini-SAR imaging radar.  The purpose of this experiment is to map and characterize the deposits within permanently dark areas of the poles.  These dark areas are extremely cold and it has been hypothesized that volatile material, including water ice, may be present in quantity here.  Our radar team has just finished the first round of analysis of data returned by the Mini-SAR for the north pole and results will soon be published in the technical journal, Geophysical Research Letters.

Mini-SAR is a lightweight, low power imaging radar.  It uses the polarization properties of reflected radio waves to characterize the lunar surface composition and physical state.  Mini-SAR transmits pulses of left-circularly polarized radar.  Typically, reflection from planetary surfaces reverses the transmitted polarization, so that Mini-SAR radar echoes from the Moon are right circularly polarized.  The ratio of received power in the same sense transmitted (left circular) to the opposite sense (right circular) is called the circular polarization ratio (CPR).  Most of the Moon has low CPR (about 0.3), meaning that a reversal of polarization is the norm, but some specific areas have high CPR (greater than 1.0).  These include very rough, rocky surfaces (such as a young, fresh crater) and ice, which is transparent to radio energy.  In this latter case, the radar penetrates the ice and is scattered and reflected multiple times by inclusions and flaws in the ice, resulting in the reflection of many same sense polarization echoes, leading to higher CPR values than normal.  High values of CPR are not uniquely diagnostic of either surface roughness or ice; we must take into account the geological setting of the high CPR signal to interpret its cause.

Many craters near the poles of the Moon have interiors that are in permanent shadow from the Sun.  These areas are very cold and water ice is stable permanently there.  Fresh craters show high degrees of surface roughness (high CPR) both inside and outside the crater rim, caused by sharp rocks and block fields that are distributed over the entire crater area.  However, Mini-SAR found craters near the north pole that have high CPR values inside, but not outside their rims.  This relation suggests that the high CPR is not caused by roughness, but by some material that is restricted within the interiors of these craters.  It is not geologically reasonable to expect rough, fresh surfaces to be present inside a crater rim but absent outside of it.  The craters that show this enhancement are all permanently cold and dark, where ice is stable.  We thus interpret this high CPR to mean that water ice is present in these craters.

Over forty small (2-15 km diameter) craters near the north pole of the Moon are found to contain this elevated CPR material.  The total mount of ice present at the pole depends on how thick it is; to see this elevated CPR effect, the ice must have a thickness on the order of tens of wavelengths of the radar used.  Our radar wavelength is 12.6 cm, therefore we think that the ice must be at least two meters thick and relatively pure.  At such a thickness, more than 600 million metric tones of water ice are present in this area.  Such an amount is comparable to the quantity estimated from the 1998 Lunar Prospector (LP) mission’s neutron spectrometer data (several hundred million metric tones).  The LP neutron spectrometer only sees to depths of about one-half meter, while we penetrate at least a couple of meters, so the neutron data would underestimate the total quantity of water ice present.

The emerging picture from many experiments on several different lunar missions indicates that the creation, migration, deposition and retention of vast amounts of water are occurring on the Moon.  Such an astounding result was totally unexpected by most lunar scientists, including myself.  The emerging picture is consistent with earlier studies from the 1994 Clementine mission and subsequent Lunar Prospector as well as the more recent reports of the presence of water-bearing minerals at high latitudes (Moon Mineralogy Mapper), the detection of water vapor in the LCROSS impact plume (a few percent water content at its target site), and a variety of new supporting measurements, such as the discovery of unexpectedly cold polar temperatures by the DIVINER experiment on NASA’s Lunar Reconnaissance Orbiter (as cold as 25 degrees above absolute zero, colder than the estimated surface temperature of Pluto).  The Moon experiences complex geological processes that were wholly unexpected before the recent results.

The quantity of water present at the lunar poles is significant; at the north pole alone, the 600 million metric tons of water there – turned into rocket fuel – is enough to launch the equivalent of one Space Shuttle (735 mT of propellant) per day for over 2000 years.  The discoveries we are now making show that the Moon is an even more interesting and attractive scientific and operational destination than we had previously thought.  The Moon is the key to sustainable human presence in space.  Its resources enable us to create a reusable, sustainable transportation system, one that can routinely access not only the Moon, but all points of cislunar space.  Once established, such a system can be used to go forward into the Solar System.

The SP-100 space nuclear reactor

Wild claims are being tossed about regarding the future U.S. space program.  Recipes for success are touted and e-mailed around – concepts based more on wishful thinking than on solid science and engineering.  My friend Rand Simberg refers to those who would replicate anew the means we devised to go to the Moon several decades ago, as having an “Apollo cargo cult” mentality (i.e., Pacific islanders waiting for parachutes to once again drop wondrous things in crates from planes, as they did during World War II).  A counterpart to the so-called “Apollo cargo cult” also exists in the space community and they rely on their own talismanic thinking – a belief in some technique or item that allows us to go farther and longer in space, with incredible new capabilities.  The talisman takes different forms for different groups, but in all cases, they ward off the evil spirits of physical and bureaucratic reality.

Early in the history of the Vision for Space Exploration, talismanic thinking was apparent with Project Prometheus.  This was a program to develop an advanced space nuclear reactor for missions to the outer Solar System – where the Sun’s rays are too weak to provide enough energy to power systems.   Used anywhere, such a capability enables activities to take place in a power-rich environment, making many necessary and routine operations easier, safer and more efficient.  Former NASA Administrator Sean O’Keefe was enamored of Prometheus, so much so that he often unintentionally overstated its capabilities.  For him, Prometheus was a talisman – a unique capability that enabled the otherwise unobtainable.

NASA Administrator Charles Bolden fancies his own talisman – the technology to “go to Mars in days and weeks, rather than months.”  Bolden is probably referring to VASIMR, the plasma rocket engine designed and undergoing testing by former astronaut Franklin Chang-Diaz.  In principle, a VASIMR-powered vehicle could go to Mars on non-minimum energy trajectories, thereby cutting transit time between planets to a fraction of that required for a chemical rocket.

VASIMR is an interesting concept and some form of it will be very useful when we are ready to travel to the outer planets.  However, one aspect about it that I have not heard mentioned by Bolden is the low mass, high power system needed to run it.  The only known systems approaching the necessary power density needed are nuclear reactors.  Which brings us back to Project Prometheus, a joint NASA-Department of Energy (DoE) effort.

Prometheus was canceled in the FY2006 budget.  It was deemed too complex and too costly for its proposed use, the Jupiter Icy Moons Orbiter.  This was a robotic spacecraft designed to tour the Jupiter system and obtain data on its satellites during multiple flybys.  Note well: this power system was thought to be both too complex and expensive for a robotic mission.  A similar system for human missions – which involves many more systems, power requirements, and propulsion – would be even more complex and expensive.  Tack on international participation and – well, you get the picture.

So where does this leave VASIMR?  Chang-Diaz notes that nuclear reactors can be launched empty and then assembled and fueled in space, presumably by human astronauts.  Thus, there are no safety considerations associated with its launch.  The problem is that the pieces of this reactor don’t exist and aren’t even being thought about being built.  For decades the DoE community has talked about a space reactor of the 100 to 1000 kW class; a VASIMR-powered Mars vehicle would need a 10 megawatt reactor.  Billions of dollars went into the SP-100 program in the 1980s and 1990s and still the reactors needed to power VASIMR exist only in the mind’s eye of some space dreamers.  The United States Navy has been building and operating nuclear reactors for over 60 years, so one would think that building a space reactor would be achievable, but practice has proven otherwise.

VASIMR is Bolden’s talisman, the magic beans that will grow a stalk that we can climb to Mars.  Such a rocket engine would be a technological breakthrough promising capabilities well beyond our current reach.  But for now, a Mars craft using VASIMR is imaginary.  Reality will not come about by spending massive amounts of money on general technology investment.  When VASIMR is finally built, it will be because it is needed for a specific application or mission.  Once again, the ends will drive the means, not the other way around.

Talismanic thinking is common in much of the current discussion about the new path for NASA.  Other talismans include cheap access to low Earth orbit, commercial transport replacing Orion, and an “exciting space goal” to engage the public.  These new dogmas (all of them means, not ends) clearly illustrate that there is no strategic thinking or thoughtful leadership guiding America’s space program.  Those at the top need to know where they are going and understand why; the fact that they currently do not bodes ill for the future of our country.

NASA Administrator Charles Bolden recently said that “he is trying to find middle ground between groups “radically” in favor of keeping the Constellation program and others lobbying for reliance on commercial space entities.”  But he is still confusing the means with the ends.  We should re-affirm that our mission is to use the resources of the Moon to build a transportation infrastructure whereby all can travel to wherever they choose as often as they want.  Our direction in space goes through the Moon or we go nowhere.

Klaus Heiss and President Reagan

My good friend Klaus Heiss is resting in the hospital after recently suffering a stoke.  Klaus is not widely known or familiar to many in the space community, but over the years, he has had a major impact on our national space program – a major player in both the Shuttle program and in helping to promote a return to the Moon.  His work is thoughtful and visionary and deserves a wide readership.

Klaus comes from the Tyrol of Austria, near the Italian border.  His academic background is in economics, specifically the economics of space transportation, but he also has considerable expertise in physics and engineering.   In the late 1960s and 70s he worked on the rationale for the Space Shuttle, calling for the development of a fully reusable, liquid-fueled version.  For a variety of reasons, such a path was not chosen and the Shuttle failed to live up to his expectations as an economical method for launching payloads into space.  In the 1980s, Klaus participated in a variety of studies for the Strategic Defense Initiative, including satellite interceptors.

In the wake of the loss of Shuttle Columbia in 2003, many were concerned about the future direction of NASA.  Why do we have a national space program?  What should we be striving for – pure exploration, space applications, or some combination of the two?  Is there some goal or objective that creatively combines these two threads of spaceflight and is it attainable on reasonable timescales and budgets?

Klaus had long held an interest and fascination for the Moon.  In the spring of 2003, he visited President Bush and Vice-President Cheney and presented to them his ideas about a return to the Moon.  In his view, making the establishment a lunar base as the next NASA goal offered the country two principal advantages.  First, the Moon is a strategic destination that is in reach within a decade or so without a substantial increase in the agency budget.  Second, he recognized both the scientific and cultural value of establishing a human community on another world.  The Moon is close and possesses the resources necessary to permit its permanent habitation.  Once there, we can use the Moon as both an observing platform and a natural laboratory for scientific and engineering research.

Klaus was tasked by the White House to develop his ideas in a more detailed manner.  He spent the next few months mapping a pathway from where we were to where he thought we should be.  His report, Columbia: A Permanent Lunar Base, cogently summarizes all the various threads of lunar return, including not only an architecture for launch and transportation (based on Shuttle-derived vehicle components) but also the spectrum of surface activities that we will undertake there.  This document was presented to the NASA Office of Spaceflight in December 2003.

I first met Klaus at a meeting on the future of the American space program convened by Buzz Aldrin in Washington DC in that same month.  At the time, there was a widespread rumor that at Kitty Hawk, during a ceremony celebrating the 100^th anniversary of the Wright brothers first powered airplane flight, President Bush would announce a major new direction for the American space program.

For years I had been advocating a return to the Moon mostly from the “bottom up” as I worked my way up the NASA chain of command from the field centers to Headquarters, telling anyone who would listen about the advantages of lunar return.  I was unaware that while I was pursuing the Moon from the bottom up, Klaus had been doing the same thing from the top down.  He knew of my work and told me that a major decision would be forthcoming from the White House and not to be discouraged by the lack of an announcement at Kitty Hawk – that I would be “pleased” with the new direction.  President Bush announced the Vision for Space Exploration about a month later, in January 2004.

As Klaus and I got to know each other over the next few years, we found that we saw space issues in a similar way.  Both of us were frustrated at the attempts by some in NASA to thwart the Vision, in some cases by slow-rolling it and in others by more deliberate action.  Yet at the same time, we both worked closely with and attempted to help our allies within the agency, a group of smart, dedicated people who were trying to do the right thing and implement the Vision, even when it wasn’t the desire of their immediate superiors.  For his leadership in fostering the Vision for Space Exploration, he was awarded the NASA Distinguished Public Service Medal in January, 2008.

Klaus was one of the first to see that the ESAS architecture (NASA’s chosen implementation path for the Vision) was unaffordable and unsustainable.  He specifically outlined a path by which the goals of permanent presence might yet be implemented, but his counsel and pleas fell on deaf ears.  Now, six years and $8 billion later, we see a new proposed budget that terminates the program designed to take us beyond low Earth orbit.  Despite the positive spin from many in the space community, a return to the Moon is as far away now as it was six years ago, before the Vision.  In fact, it’s actually farther away as much of the tooling for Shuttle parts that could enable the quick and relatively inexpensive fabrication of a moderately heavy-lift launch vehicle for the VSE are being mothballed or destroyed.

Klaus’s work on the activities of lunar settlement will stand as a lasting contribution to the literature of space travel.  We have too few clear thinkers in this business and we were indeed fortunate to have his informed and authoritative voice to help guide our journey out into the Solar System.  We need others who can clearly see the importance of a sustained lunar return to step forward and pick up where Klaus left off.

A growing catalogue of the resources of the Moon continues to spill out.  Much of this knowledge was gained through the vision and efforts of Klaus Heiss.  I am grateful for his contributions and his friendship.  Klaus will be with us in spirit as news of the Moon and its resources is presented at the annual Lunar and Planetary Science Conference next week in Houston.

Our new space program. "You think that you hate it now... But wait till you drive it."

The release of the proposed NASA budget and new “direction” has led to an intense “cage fight” in the blogosphere over who has the best rocket and the best architecture.  Many “New Space” advocates are ecstatic, viewing the cancellation of the Constellation program as vindication of their view that:  a) this was a stupid architecture to begin with; and b) the purchase of launch services by NASA is more desirable than the development of same by the agency.  In the other corner, defenders of the existing program and paradigm see human spaceflight as still largely an experimental activity and that by contracting for launch services, astronauts’ lives will be put in danger, leading to the eventual termination of America’s human spaceflight program.  Both sides are locked in a fierce battle over the ownership of the “how,” while seemingly unconcerned as to the “why” or the “what” they are fighting for.

Once again the debate focuses on launch vehicles, the need or lack thereof for a heavy lift vehicle, and all the wonderful new technical development and leaps forward possible once NASA is freed from its responsibility to build and operate a space transportation system.  I agree with the New Space people that alternative options for launch and orbit are desirable and that a flexible, extensible architecture is the way to move beyond LEO.  On the other hand, I agree with the “Ares huggers” that this change will not result in the space utopia its advocates promise and that an agency saddled with an unworkable approach is a ripe target for elimination.

Those cheering the new path should step back from their celebrations, take a sober look at the landscape and ask themselves, “Now what?”  The “new path” has no mission.  Despite what many believe or have said, Project Constellation was not same thing as the Vision for Space Exploration (VSE).  Constellation was the implementation that NASA chose to carry out that mission.  The VSE was both a set of destinations and a group of specific activities at those locations.  The Vision’s objective was to give us new spaceflight capability by learning to use the material and energy resources of space, first on the Moon and then from other objects in space.

The new policy indicates a lack of understanding of the difference between “means” and “ends” within both NASA and the current administration.  When they cancelled Project Constellation, the Vision was terminated as well.  And what was put in its place?

Nothing.

All of the current hand wringing and angst is focused on which rocket and spacecraft to build.  But to what end?  The “Flexible Path” concept came from the Augustine Commission.  It’s main focus was to find an affordable way to move people beyond low Earth orbit.  Using their concept, we would visit places beyond low Earth orbit that had very low gravity – libration points, near Earth asteroids, and the moons of Mars.  The supposed advantage of such places is that they do not require a large propulsive maneuver to land on (or more accurately rendezvous with) them.  Thus, the supposed enormous cost of building a landing vehicle is saved.

The “new path” called for in the budget envisions a government funded and commercially built and operated space launch system, freeing NASA from the necessity of building rockets.  The agency would “invest” in new technology.  Somehow, these new and wonderful approaches will lead to the spontaneous generation of a space faring infrastructure capable of taking us beyond LEO into the Solar System – anywhere and everywhere.  But to do what?

NASA Administrator Charles Bolden seems to think that a return to the Moon should be ruled out because “there are already six American flags there.” It is hard to imagine that he believes that the purpose of space exploration is to plant a flag and move on to the next destination.  Such a template will exhaust possible destinations quickly.  If the goals of travel beyond LEO are more significant than that, what are they?  What will people do at an asteroid?  What do we get from such a trip?  What capability does it create?  What are we buying? Again, the “means” and “ends” argument attempts to focus on outcome.

We had a considered and well crafted strategic direction in space – to go to the Moon and use its resources (which we now know are even more abundant and accessible than we thought) to create a new transportation system that will reduce costs and increase access to cislunar space.  That mission was not just the proposal of the former President; it was endorsed by two different Congresses (in 2005 and 2008), under the leadership of different parties, and both times, by huge bipartisan majorities.  The Vision for Space Exploration is our national space policy and will be until the Congress passes a new authorization bill, changing the mission and goals of the space program.

Currently, the proposed budget casts aside this hard-won, bipartisan policy and puts nothing in its place.  This new policy is striking in that, rather than serving America’s national security, economic and scientific interests, it undermines them.  The “new path” was apparently put together by a very small group of people, without significant debate or input from outside sources.  Whatever the circumstances of its genesis, it is poorly conceived; if it were well considered, we would know exactly where we were going, what we would do there, and what benefits would accrue from these voyages.  The idea expressed by some in the blogosphere, that we will now be able to “go everywhere and do everything” is ludicrously naïve.  Given the past performance of this agency (or any agency) given no direction, random motion is a much more likely outcome, at $20 billion per year.

If the current architecture is broken or unaffordable, fix it or change it.  If getting NASA out of the rocket-building business is the right way to go, do that.  But don’t discard our strategic direction.  The space program can survive a change in the business model of its implementing agency; it won’t survive fecklessness and a complete lack of direction.

The administration proposes; Congress disposes

The release of the new proposed budget for NASA has unleashed a blizzard of news articles and commentary.  The administration proposes to terminate Constellation, the agency effort to design and build a new space transportation system to carry people to low Earth orbit and beyond.  In its place, they plan to let contracts with several companies to provide orbital launch and spaceflight services, both as transport to ISS and to “destinations beyond LEO.”  This major change in the agency’s business model follows in the wake of last summer’s Augustine committee report, which concluded that NASA’s “program of record” to return to the Moon and beyond was inadequately funded and possibly, misdirected as well.

The Augustine “Flexible Path” was an architecture designed to take people beyond LEO, but to low gravity targets: L-points, near-Earth asteroids, and Phobos and Deimos, the asteroid-like moons of Mars.  The idea behind that concept was two-fold.  First, it was a way to send people into deep space without the very high programmatic expense of developing a lunar landing spacecraft.  Given that Constellation is significantly over budget, cost control is certainly an issue.  The second motivation for FP was the feeling (not explicitly stated in the report, but clearly implied) that the agency plan for lunar return was largely a repeat of the Apollo experience of 40 years ago.  The strength of this impression varied among the committee members, with some thinking that the chosen architecture was simply the wrong approach while others questioned the value of going to the Moon at all.  The new proposed budgetary direction seems to follow the Augustine Flexible Path (FP).

I have previously discussed what I perceive as the most significant problem with FP, namely, that it is activity without direction.  The administration’s budgetary version of this path confirms this perception.  Much verbiage is thrown around about multiple missions to all sorts of destinations, blazing new trails with new technology, trips to Mars that last weeks instead of months, and “people fanning out across the inner solar system, exploring the Moon, asteroids and Mars nearly simultaneously in a steady stream of firsts.”   But nowhere in the budget documents or agency statements is there anything about the mission that we are undertaking.  So we’re going to an asteroid.  What will we do there?  Why are we going there?  What benefit accrues from it?

The Vision for Space Exploration (VSE) of 2004 not only laid out a clear path, but also described exactly why such a path was being taken.  It is not a repeat of the Apollo experience.  We go to the Moon to learn how to create a sustainable human presence in space.  We do this by experimenting with and learning to use the material and energy resources of the Moon to create new space faring capability.  These skills enable us to build a space transportation infrastructure that allows routine access not only to the Moon, but all of cislunar space (where our space assets reside) and the planets beyond.  All of this activity is to be accomplished under the existing budgetary envelope; as there is no deadline, we trade time for money.

Many conflate the VSE with Constellation, the agency’s program to build the Ares launcher and Orion spacecraft, but they are different and distinct.  The former is a strategic direction; the latter is an implementation of that direction.  This is not some academic distinction; it goes to the essence of the current debate about NASA and the space program.  Virtually all of the argument and debate about our future in space has been about means rather than ends.  Launch vehicles, spacecraft, and architectures have been grist for the mills of the space blogosphere.  Beyond a vague notion that people should “move into the Solar System,” the purpose and meaning of that movement has been articulated much less often.  Partly that’s because different people have differing notions of what those motivations should be – science, settlement, curiosity, and technical innovation all have their adherents.  But if you do not clearly understand what your mission is, you are not likely to successfully implement it.

The VSE was a clear strategic direction.  It not only identified the path forward, but also the specific activities that would enable that path to be followed.  The new budget outlines the means (new commercial launch and transport) but not the object of our space program.  But more critically, it discards the clear and practical direction of the original VSE.  Before the new budget, we knew exactly where we were headed and why: a return to the Moon to learn how to live and work productively on another world.  Now, all we know is that at some point in the future, we will somehow go somewhere to do something.  Or other.

I wrote recently about a variant of the Flexible Path architecture outlined at the blog Vision Restoration.  I think that this approach has a lot of merit, but suggest one critical modification: it does not have a statement of the mission.  The VSE in its original guise should be stated up front and made a clear and unalterable part of the architecture.  If during the course of the program the implementation somehow falls short, change the implementation, not the mission.  The failure to do this in the Constellation Program led us into a blind alley of cost and schedule overruns, the Augustine committee, and now, cancellation.

This new policy will increase NASA’s natural tendency to engage in organizational “Brownian motion.”  We are already seeing agency leaders call for new studies to determine what will be done at the (so far unspecified) new destinations.  The current program looks upon itself as a transportation architecture; the activities undertaken at any given destination are irrelevant.  The new “direction” outlined in the budget request is similarly focused on means (e.g., commercial launch and transport) rather than ends (e.g., What will humans do at Earth-Sun L-1?).  And it will likely come down the same path, as indeed it appears to be starting to.  NASA as an organization will adjust to this; after all, viewgraphs are easily changed and mission studies easily re-written.  But what about the aerospace industry?  They find it very difficult to pivot on a dime when the direction changes.

I’ve often written about how I think the VSE ought to be implemented and have found the existing program of record wanting in several respects.  But at least it aimed in one direction.  We need a program plan that gets us beyond LEO using small, incremental, cumulative steps and the new model promises to do just that.  But small, incremental steps taken in random directions yield uncertain progress.

What is your mission?  It’s not just the most important thing; it’s the only thing.  NASA forgot that during the last 6 years.  Now, the White House has joined them.

Tourists arrive at the new world (Library of Congress)

Yet again, the U.S. space program is in the slough of despond, whereby previous assumptions are questioned, the current path is discarded, the program is re-directed, and luminous enthusiasm heralds the new direction…

And then it all tapers off to nothing.

As long as we are navel-gazing during this policy hiatus, I want to examine a topic that many think is self-evident: what activities do we mean by the word “exploration?”  NASA describes itself as a space exploration agency; we had the Vision for Space Exploration.  The department within the agency developing the new Orion spacecraft and Ares launch vehicle is the Exploration Systems Mission Directorate.  So clearly, the term is tightly woven into the fabric of the space program.  But exactly what does exploration encompass?

Exploration can have very personal meanings, such as your own exploration of a new town, or a new and unknown field of knowledge.  Here, I speak of the collective, societal exploration exemplified by our national space program.  This exploration began in 1957, when the launch of Sputnik by the Soviet Union initiated a decade-long “space race” of geopolitical dimensions with the United States.  That race culminated with our first trips to the Moon.  Once its primary geopolitical rationale had been served, Moon exploration was terminated.  Since then, the “space program” has been astonishingly unfocused – drifting from a quest to develop a reusable spacecraft to building orbiting space stations – and despite numerous studies affirming needed direction, unfulfilled plans to send humans back to the Moon and eventually on to Mars.

When the race to the Moon began 50 years ago, space was considered just another field of exploration, similar to Earth-bound exploration of the oceans, Antarctica, and even more abstract fields such as medical research and technology development.  Moreover, many used the term “frontier” when speaking about space, touching a very familiar chord in our national psyche by drawing an analogy with the westward movement in American history.  What better way to motivate a nation shaped by the development of the western frontier than by enticing it with the prospect of a new (and boundless) frontier to explore?  After all, we are descended from immigrants and explorers.  Over time however, few recognized that there had been a shift in the definition and understanding of just what exploration represented.

Starting around the turn of the last century, while still retaining its geopolitical context, exploration became closely associated with science.  Although first detectable in the 19^th Century exploration of America and Africa, the tendency to use science as the rationale for geopolitical exploration reached its acme during the heroic age of polar exploration.  Amundsen, Nansen, Cook, Peary, Scott and Shackleton all had personal motivations to spend years of their lives in the polar regions, but all of them cloaked their ego-driven imperatives in the mantle of “scientific research.”  After all, the quest for new knowledge sounds much nobler than self-gratification, global power projection or land grabbing.

Science has been part of the space program from the beginning and has served as both an activity and a rationale.  The more scientists got, the more they wanted.  They realized that their access to space depended upon the appropriation of enormous amounts of public money and hence, supported the non-scientific aspects of the space program (although not without some resentment).  Because science occurs on the cutting edge of human knowledge, its conflation with exploration is understandable.  But originally, exploration was a much broader and richer term.  Which brings us back to the analogy with the westward movement in American history and the changed meaning of the word “exploration.”  A true frontier has explorers and scientists, but it also has miners, transportation builders, settlers and entrepreneurs.  Many are perfectly satisfied to limit space access to only the former.

“Exploration without science is tourism.” – Statement of the American Astronomical Society on the Vision for Space Exploration, July 11, 2005

This fatuous quote accurately reflects the elitist, constricted mindset of many in the scientific community.  In one fell swoop, the famous explorers of history – Marco Polo, Columbus, Balboa, Drake – are consigned to the category of  “tourist.”  Overcoming great difficulty and hardship, these men sought new lands for many varied reasons.  Exploration includes obtaining new knowledge but it does not end there; it begins there.  The quest for new lands has always been a search for new territories, resources, and riches.  Historically, survival and wealth creation are stronger drivers of exploration and settlement than curiosity.

What is missing from our current program of space exploration is a firm understanding that it must generate wealth, not just consume it.  Exploration is more than an experiment.  The idea of space as a sanctuary for science has trapped us in an endless loop of building expendable hardware to support science experiments.  Once the data are obtained, of what use is an empty booster or a used rover?  We’ve “been there” and a pipeline of new inquiry awaits, to be facilitated by new spacecraft and new sensors designed to reach new destinations of study.  Hugely expensive equipment must be developed to support science while the idea of creating transportation infrastructure or settlement is branded as “budget busting” (i.e., manned space exploration cuts into science’s budget).  So “exploration” lives to enable science, period.

This is our current model of space exploration.  I contend that it is not exploration as historically understood and practiced.  Traditionally, science (knowledge gathering) was a tool in the long process of exploration, which included surveys, mining, infrastructure creation and settlement (all advanced and protected with military assistance).  This was the model of national exploration prior to the 20^th Century and it is readily applicable today – if we change our business model for space.  What is needed is the incremental, cumulative build-up of space faring infrastructure that is both extensible and maintainable, a growing system whose aim is to transport us anywhere we want to go, for whatever reasons we can imagine, with whatever capabilities we may need.

These changes do not require that an ever-increasing amount of new money be spent on space.  Instead, true exploration requires only the understanding that it must contribute more to society than it consumes.  And the American people have every right to expect as much in return for their years of supporting NASA.

Teleoperated robots can emplace and build much of the lunar outpost infrastructure prior to human arrival (Astrobotic Technology Inc.)

In an interesting post at Vision Restoration, “Ray” tackles the desultory Flexible Path (FP) architecture of the Augustine committee, which calls for human missions to low gravity destinations and delays missions to the lunar and martian surface.  The problems he finds with FP are similar to points that I’ve discussed in a previous post.

The principal rationale for doing Flexible Path rather than the current program for return to the Moon is to avoid the cost of developing a new surface lander spacecraft for humans (either lunar or martian), which Augustine pronounced budget-busting for NASA.  By being “flexible” and avoiding deep gravity wells, the Augustine committee saw a low cost way to send people beyond LEO.  However, the Orion crew module and some type of heavy-lift booster still must be built.

Augustine committee member Jeff Greason discussed the FP architecture during a recent appearance on The Space Show.  Jeff pointed out that many people missed the principal rationale for the advancement of FP as an alternative to the existing program – that while we cannot afford the current ESAS architecture because of the requirement to do several developmental projects simultaneously (or nearly so), we might be able to afford to do it sequentially, so that development of the Altair lunar lander would only begin after we had developed and flown the Orion and its new heavy-lift launch vehicle.  In his conception of FP, Jeff sees increasing space faring capability over time as robots and people visit new and more distant destinations.  The FP destinations described in the Augustine report are the Lagrangian-points, near Earth asteroids, and martian moons Phobos and Deimos.

Ray points out that the two alternatives discussed in the Augustine report (Moon First and FP) assume a roughly $3 billion per year increase in the NASA budget.  He suggests that this is unlikely, especially on a continuing basis, a supposition made even more credible by recent stories in the space press.  The alternative he offers to Augustine’s FP takes a slightly different tack to the cost problem.  Ray’s solution, called Flexible Path to the Moon, shortens the destination horizon for FP and restricts it to cislunar space (GEO, the Earth-Moon L-points, and lunar orbit).

With Flexible Path to the Moon, we develop routine access to all cislunar space, which adds important national security and economic dimensions to the human spaceflight program.  Ray would defer not only the Altair lander but also (and this is critical) the new, proposed heavy lift vehicle called for by the Augustine report.  Instead, FP to the Moon uses existing and future commercial launch vehicles for LEO access and for the subsequent build up of transfer nodes, in-space re-fueling of vehicles, propellant depots and other features of the Augustine FP architecture.  Ray’s plan further calls for “a large number” of robotic missions to the Moon and other possible destinations prior to human arrival.

I like this architecture and have advocated a very similar approach that builds up space-faring capability incrementally and cumulatively—take small, affordable steps and make time and schedule the free variables.  We make progress as we can with a sustainable architecture and build an infrastructure that is cumulative, inevitable and inexorable.  One thing should be added to Ray’s architecture:  a statement of the “mission.”  The purpose of lunar return is to learn how to use the resources of the Moon and space to create new capabilities and a sustainable human presence in space.  This mission statement fits well with Ray’s mission architecture.  The significant level of robotic missions that he advocates in Phase 1 can be focused specifically on resource prospecting, characterization and demonstration.  We can begin to produce resources using robotic missions and machines teleoperated from Earth well before the arrival of the first humans, who will then have the assets of life-support consumables, propellant, and electrical energy to draw on when they arrive.

The Flexible Path to the Moon offers the build-up of new technologies and capabilities in space by using an incremental approach that falls within existing budgetary constraints.  It forgoes the building of a new heavy lift launch vehicle by creating a reusable, extensible space transportation system infrastructure using existing launch vehicles.  And it focuses efforts and builds infrastructure in cislunar space, where virtually all of our assets reside.  These are the stepping stones we need into the Solar System.

A robotic mission sends samples back to Earth: What can we learn from them?

Deciphering the cratering history of the Moon is an important scientific problem.  My previous post discussed early lunar cratering history, the apparent impact “cataclysm” 3.8 billion years ago, its significance to Earth’s early history and how remaining questions might be resolved by collecting and returning new samples from the Moon.  Here, I will describe the scientific difficulty and critical importance of planetary sample collection and analysis.  With so many demands on NASA’s budget, we need to approach this problem carefully, making every effort to maximize the prospect that we obtain not just samples but the right samples to answer the question of the Moon-Earth cataclysm.

NASA has announced that the proposed New Frontiers Moonrise robotic sample return mission is one of three selected for detailed concept study.  The objective of this mission is to sample, date and analyze the composition of the impact-generated rocks produced by the largest and oldest crater on the Moon, the South Pole-Aitken (SPA) basin.

The return of surface samples has the potential to answer many important scientific questions.  How do we reconstruct the history of a planet from rocks returned from its surface?  What are some of the difficulties in such a reconstruction?  How well do we really understand the history of the Moon from returned lunar samples?  Because context is vital to the correct interpretation of sample return data, these questions must be understood and considered, and underlie the mission strategy.

A great deal can be learned from remote surface measurements, but some properties can only be measured to very high degrees of precision by using returned samples.  One key piece of information that is difficult to measure remotely is a rock’s age (measured by its radiometric isotopes).  This determination requires a significant sample preparation, handling, and precision measurements; in some dating methods, we must literally take the rock apart, grain-by-grain.  The machinery needed to measure isotopic composition tends to be big, massive, and power hungry, all undesirable properties for lunar and planetary payloads.

Geologists collect samples because they cannot bring into the field all the complex and sophisticated equipment used to analyze and describe the physical, chemical and mineral properties of planetary crusts.  Samples allow them to conduct many different kinds of measurements in a controlled environment, eliminating external factors that can contaminate results.  In addition, samples have long-term value in that they can be stored, archived and examined in detail (sometimes by newly invented techniques) as concepts and understanding change.  It is for this reason that lunar sample studies continue to unravel new aspects of the complex history of the Moon 40 years after Apollo 11.

We are able to design a spacecraft to collect rocks and soil and return them to Earth.  After analysis, we have lots of data and numbers, but not necessarily any new understanding.  Context is important in translating sample data into knowledge.

The geologist in the field must collect samples carefully; field work is not just picking up rocks – it is the attempt to unravel and comprehend the spatial and temporal make-up of planetary crusts.  Samples must be representative of the larger, regional geological units they come from.  A sample must be of the appropriate size (coarse-grained rocks need larger samples than fine-grained rocks to be representative of their parent units).  If possible, we must collect rock samples from outcrop (in place bedrock); rocks obtained from loose pieces on the ground (called “float” by geologists) have uncertain or unknown context and hence, the conclusions we draw from such samples may not apply to regional units.  And when done on the Moon or another planetary body, all of this activity must conform to the constraints imposed by the flight system, such as total mass and volume limits for returned samples.

Recently, many countries have flown sensors that have yielded compositional information and globally mapped the Moon.  From these data, we can determine chemical and mineral compositions of the geological units of the Moon (which are delineated by extent, morphology and physical properties).  When this information is combined with data from returned samples, we can characterize the unit and its history even more fully than traditional field work, where intense, protracted ground study is possible.  This is the promise of the new approach – allowing us to combine the low fidelity but broadly distributed data of remote sensing with the highly detailed but narrowly restricted information provided from samples.

However, due to the very nature of the Moon, there are significant geological complications that must be taken into account.  Exposed bedrock is rare.  A thick cover of regolith is everywhere on the lunar surface.  In the highlands (the oldest geological units on the Moon), there may be no bedrock at all, the surface having been thoroughly pulverized into regolith by four billion years of impact bombardment.  Consequentially, the context of most Apollo highland samples remains poorly understood.  Exquisitely detailed measurements have been made on these rocks but we still cannot be certain about what they represent.  Was there a cataclysm at 3.8 billion years ago?  Currently, we are left wondering if we have sampled one, a couple, or a dozen basins.

During the Apollo missions, the astronauts did their best to sample and describe the context of representative rocks during collection, but the geological setting of most samples is still guesswork.  The location of the samples returned by a robotic spacecraft will be documented to within a fraction of a millimeter.  But as they are collected from regolith, their context will remain purely statistical.

By collecting hundreds of relatively small rocks (but still large enough for precision measurement) the argument is made that we will collect the desired SPA basin melt sheet through sheer statistical certainty.  I suspect that the mission might well do this.  But what about their context?  We need to know which of the pebbles collected are from the basin melt sheet.  In miniature, this situation duplicates and leaves us with exactly the same issue we currently have with the Apollo samples—which rocks represent the basins we intended to sample?  With few exceptions, despite having global remote sensing data to provide context, we still do not know which (if any) impact basins are represented in the collections, which keeps our scientific understanding hobbled by degrees of uncertainty.

A simple “grab” sample from a relatively young and unmodified geological unit on the Moon could solve a major problem.  A robotic spacecraft sent to the youngest lava flow on the Moon (dated relatively by crater density) could establish that flow’s absolute age to high precision with a fair degree of certainty.  As the age of the targeted geological unit increases, such certainty would decrease as younger events and deposits contaminate and disrupt the continuity of the older units.

The Moonrise mission proposes to sample the oldest preserved terrain on the Moon—the melt sheet floor of the SPA basin.  Younger units (craters, basins, and maria) are everywhere in this basin, superposed on top of the SPA melt sheet.  Although pieces of the original basin floor may be preserved in places, we will not know in advance what those pieces should look like, leaving us with uncertainty over what was collected from the mission.  In short, many samples will be collected, much data will be accumulated, and uncertainty will remain as to what it all means – the same knowledge gap we currently have with the Apollo samples.

The Imbrium basin immediately after formation, ~3.85 billion years ago. Artwork by Don Davis.

NASA recently announced that it has down-selected three New Frontiers mission concepts for additional study.  One of these missions, Moonrise, proposes to return rock and soil samples from the floor of the largest impact crater on the Moon, the South Pole-Aitken (SPA) basin, centered on the southern far side.  Not only is this the largest basin on the Moon, it is also the oldest, as evidenced by a high density of impact craters superposed on top of its deposits.  But knowing that it is the oldest basin does not tell us exactly when it formed.  Samples collected from its floor could potentially determine exactly when, during the early history of the Moon, it was created.

Why is the absolute age of this feature important?  When lunar samples are returned to Earth as they were by the Apollo missions forty years ago, they are subjected to virtually every conceivable chemical and mineral analysis we can imagine.  From those studies we have reconstructed a rough outline of lunar history and the processes that have shaped it.  From this work (which produced reams of detailed data on the elemental composition and make-up of the Moon) came the startling discovery that, not only is the heavily cratered crust of the Moon very old (older than 3.8 billion years), but that the largest impact features of that crust seemed to have formed at the very end of that early period.

The Moon’s molten crust solidified 4.3 billion years ago. Virtually all highland rocks assembled in large impact events date from around 3.8 billion years ago.  Because it was believed that many of these impact events had been sampled by the Apollo missions, it was inferred that the Moon underwent a massive bombardment of large body projectiles, all closely sequenced at that time.  This time period is referred to as the lunar “cataclysm” or the “late heavy bombardment.”  As both Earth and Moon orbit the Sun at the same distance, an impact cataclysm affecting the Moon also would have affected the early Earth.

A late, cataclysmic bombardment of the Earth-Moon system was not predicted by the then-existing models of lunar formation and growth.  In an unexpected turn, this time period (3.8 billion years ago) was significant in another respect, as it is the oldest epoch from which we have preserved fossil (bacterial) life in Earth’s rock record.  Does this mean there is a connection between the end of the early, heavy impact bombardment and the emergence of life on Earth?  It is very tempting to make this connection but when missions to the Moon ended, our ability to continue down this path of scientific inquiry also ended.  If we are ever able to draw such a paradigm-changing conclusion, we must first determine if the lunar cataclysm really happened.

Two things about the Apollo samples must be considered.  First, all were collected from six landing sites in the vicinity of the central, equatorial near side.   The large Imbrium basin is one of the youngest on the Moon—it subdivides lunar history and determining its absolute age was a top priority; at least two of the Apollo mission sites were chosen to address the composition and age of the Imbrium basin and two (and possibly the remaining four) additional sites are well within the possible influence of this large feature.  Thus, although we cannot be certain, many of the Apollo highland samples may contain the imprint of this single, watershed event, obscuring the record of earlier impacts.

Second, the nature of the Moon itself works against our understanding of the geological context of the returned samples. The Moon has had a complex history, whereby rocks were thrown hundreds of kilometers across its surface, mixed up with other deposits thrown out from other craters and basins, along with periodic lava flooding.  The continuous impact bombardment of the Moon for billions of years has “sandblasted” the crust into a crushed mixture of rock and fine powder (called regolith) that covers the surface.  True rock outcrop is hard to find and virtually none of the Apollo missions sampled it.

Although a lunar sample can be subjected to excruciatingly detailed measurements and age determinations, such data are valueless unless you are able to relate the sample to some larger, regional geological unit.  In the case of the impact cataclysm, how many and which basins did the Apollo missions sample?  Unless we can answer that question with some certainty, we cannot be sure that a “cataclysm” occurred – we may be looking at only the last (or last few) largest basin-forming impacts.

To resolve the issue of the cataclysm, we must collect samples from older, distinctly different impact basins, preferably far removed from the zones where Apollo explored.  Hence, we desire to collect samples from an area exactly opposite to the near side Apollo sites—the far side’s South Pole-Aitken, the largest and oldest basin on the Moon.  If we sample impact melt from this event, we could determine the age of SPA with a degree of confidence and understand whether all basins formed at nearly the same time (which would be the case if SPA is the same 3.85 billion year age as the near side Imbrium basin, sampled by Apollo) or if the formation of the basins was spread out over 400 million years, as would be the inference if SPA is 4.3 billion years old.

Obtaining this key sample would be monumentally important for lunar science.  Does this sound too good to be true?  Perhaps, but it is exciting to anticipate the possibilities of such a discovery.

In my next post, I will discuss some of the difficulties in deciphering the cratering history of the Moon from its rocks.

Flexible Path -- Metro Map to Nowhere (Augustine Report)

Hot rumor has it that, like Christmas, the Obama Administration’s response to the Augustine Committee Report, Seeking a Human Space Program Worthy of a Great Nation, is imminent.  Much excitement is discernible in the space blogosphere that a major change is at hand.

The Augustine Committee report concluded that NASA cannot execute the existing Program of Record (POR) of moving humans beyond low Earth orbit (LEO) to the Moon at existing or projected levels of funding.  The report offered up “Flexible Path” (FP), an alternate beyond LEO mission architecture of sending humans to asteroids and other destinations.

Flexible Path is billed as a low-cost alternative to the POR.  It avoids going to the Moon, a destination viewed by the Augustine Committee chairman as a repeat of Apollo (a defensible position, at least in terms of the current plans by NASA’s Exploration Systems Architecture Study).  FP describes a trans-LEO architecture that uses fuel depots and visits Lagrangian-points, asteroids and the moons of Mars.  By not building a “costly” lander spacecraft for descent into the gravity well of the Moon, NASA can “save” money.  The Augustine Report envisions human trips (in terms of total mission duration and remote-from-Earth operations) to L-points and asteroids as intermediate steps to human missions to Mars, their chosen “ultimate destination” of human spaceflight.

Many space advocates see great advantages to FP.  It relies on the idea of propellant depots, where fuel is cached at staging locations (e.g., Earth-Moon L-1; see below) and human vehicles are re-fueled in space for voyages beyond – trips destined for places at which no additional significant propulsive maneuvers are required.  Thus, its targets are theoretical points in space or objects with very low surface gravity, such as near-Earth asteroids (rocky objects with orbits between Earth and Mars, not those in the asteroid belt, between Mars and Jupiter) or the small, asteroid-like moons of Mars.  The latter are particularly interesting in that they could allow humans to control (teleoperate) robots on the surface of Mars with a near-instantaneous response, eliminating the tens-of-minutes time delay of radio communication with Earth.  Such operations might permit true field geological exploration of the surface of Mars without the necessity of descending into the planet’s relatively deep gravity well.

The Lagrangian points (also called libration or L-points) are quasi-stable spots in space that are stationary with respect to two or more objects.  For example, if you draw a line between Earth and Moon, it will revolve like the hand on a clock around the center of the Earth.  If a satellite is put at a point on that line such that its period of revolution is identical with the Moon’s, it will appear to be stationary in space relative to both Earth and Moon, even though it is flying through space just as fast as the Moon.  L-points are found in relation to any two bodies, including Earth-Moon, but also Earth-Sun.  They have many advantages as observation points, where satellites or telescopes can point and stare at targets in space for long dwell times and as staging areas for trips to other destinations.

So what’s the problem with FP?  At first glance, it appears to be an innovative way to move people beyond low Earth orbit at a relatively low cost.  Advocates claim that human trips to destinations never visited by people are more exciting than repeating what we did 40 years ago and that by investing in things like depots, we get a flexible, extensible space infrastructure that will ultimately permit routine access to all destinations.  Why complain about such a thing?  Especially as many have advocated exactly such an approach for the return to the Moon, an approach sorely lacking in NASA’s existing plans.

To be blunt, the difficulty with Flexible Path lies in its motivations, assumptions and likely implementation.  Development of FP by the Augustine Committee was driven largely by their determination that NASA’s chosen architecture for lunar return (ESAS) is unaffordable.  Assuming that movement of people beyond LEO is desirable, FP offers an allegedly low cost path to accomplish such.  But to what end?  The Augustine report is a bit vague as to the objectives and goals of the various FP missions.  Mentioned is the servicing of telescopes at the L-points; the problem is there are none, at least at the moment.  The James Webb Space Telescope is not yet launched, nor is it designed for human servicing.  The L-points are empty spots in space; there’s nothing there except what we put there.  In that sense, as a destination for people, it is no different from low Earth orbit, except that being outside the Van Allen belts (which protect astronauts on the ISS and Shuttle,) the radiation hazard is much greater.

The Augustine Report indicates that human missions to asteroids—Near Earth Objects (NEO), could yield valuable information, including gathering strategic information for the possible mitigation of asteroid collision with the Earth.  Yet such targets are potentially dangerous.  Some NEO asteroids have very high rates of rotation (on the order of an hour or less) making close approach very hazardous, except near the poles.  Many asteroids are loose piles of rubble and co-rotating pieces of debris in the near field of such bodies could pose a hazard to a human vehicle.  The Orion spacecraft must be completely depressurized to allow astronauts to egress and explore an asteroid with EVA, so having all the crew in suits would be required.  Exploratory capability would be very limited, on a scale similar to that of Apollo 11, the first lunar landing.

The several weeks-to-months duration of such mission will likely require the development of a “mission module,” with significant life-support, power, and environmental control.  Thus, selecting this path over the lunar surface does not relieve the agency from the task of developing and qualifying a completely new spacecraft, so the alleged “savings” of not building a lander are gobbled up by expenditure on the mission module.  Lockheed-Martin, contractor for the Orion spacecraft, has come up with a clever “kissing Crew Modules” concept whereby two Orion spacecraft are docked together, doubling the available interior space and consumables.  However, this arrangement complicates the mission design.  With two separate vehicles (requiring two dangerous re-entries), this configuration (with no airlock or docking module) has little exploratory flexibility.  With such architectural difficulties and the “safety first,” risk-aversion-at-any-cost sensibility expressed in the report, a NEO mission is probably a non-starter, or more likely, it will morph into a multi-year “study.”

The programmatic assumption behind FP is that lunar return is “boring” and trips to new destinations will somehow “excite” the public and sustain the NASA budget.  The problem with this reasoning is that it’s not public excitement that is needed – it’s public support.  People will support things that aren’t exciting, if there is some perceived value to it.  A return to the Moon to develop and utilize its material and energy resources and create new space faring capability may not be “exciting” but it certainly is productive and useful.  It allows us to build an extensible, maintainable, expandable, affordable transportation system, serving many purposes, thereby moving beyond the existing spaceflight paradigm: Design, Launch, Use, Discard (and Repeat.)  The Committee’s assertion – that building a lander to get into and out of the Moon’s gravity well makes lunar return unaffordable – is ludicrous.  It’s not the Altair lunar lander that’s eating NASA’s lunch; it’s the development of two entirely new (and arguably unnecessary) Ares launch vehicles.

Repeating what we did 40 years ago is not the reason for lunar return, although, I understand the confusion.  Here was a great missed opportunity for the Committee – they could have pointed out that NASA flubbed the implementation of its lunar mission from the beginning, largely because the agency never really grasped the rationale behind going to the Moon, thereby leaving others unable to embrace or articulate the mission.  Perhaps the Committee didn’t point this out because they didn’t understand it either.  Or perhaps because so much money has already disappeared down the black hole of Ares development, it was deemed easier to frame the report in the familiar terms of hardware procurement rather than focus on the objectives of the mission.

The above dissection of U.S. space policy leads us to the question of how NASA would implement Flexible Path.  The lesson to be drawn from NASA’s Exploration Systems Architecture Study – whose fiscally unsustainable architecture led to the creation of the Augustine Committee in the first place – is that the agency only knows one way of conducting business: the Apollo template.  This business model calls for big rockets, big infrastructure, a large marching army, and big budgets.  Who believes NASA would implement FP differently than how they’ve planned a return to the Moon?  The Augustine Committee itself (largely made up of former NASA employees and agency contractors) claims that “heavy lift launch vehicles are essential for human trips beyond LEO,” a clear expression of the Apollo mindset, yet a statement that, objectively speaking, simply isn’t true.

In other words, changing the focus of our destination from the lunar surface to Flexible Path doesn’t solve anything.  Building big rockets and throwing away 95% of the vehicle leaves no lasting infrastructure in space and prevents access to the material and energy resources of the Moon, negating the original intent and beauty of the Vision for Space Exploration (VSE) – to learn how (or whether, if you prefer) to use those resources to build sustainable, extensible space faring infrastructure.  The chorus of approval that you hear in the space press for FP is based largely on wishful thinking.  Flexible Path, if implemented by NASA, will reflexively follow the existing panem et circenses paradigm, abandoning any hope of ultimately changing an outdated spaceflight business model.

A $3 billion vaccine won’t rid NASA of this disease.  Only a renewed sense of purpose can save the patient.

Another time, another place

A recent discovery from the Spitzer Space Telescope may yield new insight into the origin of our own Moon.  Although this discovery was in the news some time ago, the advent of the Augustine report and the LCROSS mission results have eclipsed it.

The Spitzer Telescope found evidence for a planetary collision around the star HD 172555, about 100 light-years away from our Solar System.  This evidence was a heat signature associated with spectral evidence for silicon monoxide gas (a fairly rare substance) and glassy silica dioxide, a common form of silica glass found associated with volcanoes on Earth.  These substances were found associated with a large cloud of silicate debris:  the ground-up and pulverized parts of the outer portions of two rocky planets.  The evidence suggests that two planets collided with each other at relative speeds exceeding 10 kilometers per second.

This set of circumstances is (more or less) the same that we expect in the aftermath of the currently favored model for the origin of our own Moon.  Traditionally, Earth’s Moon was considered to have formed in one of three different ways.  One model called for Earth and Moon to accrete (assemble) from a collection of small bodies simultaneously; with great imagination, this model was called “co-accretion.”  The second idea called for the Moon to form somewhere else in the Solar System and then be “captured” into orbit by a near-miss encounter with the Earth.  The last model of “fission” suggested that the Moon was ripped from the body of the Earth at a very early stage of our history when it was molten (or nearly so) and spinning very quickly.  This spun-off piece of molten slag then became our Moon.

Although each of these models had its proponents in the days before and immediately after the Apollo missions, none of them seem to simultaneously satisfy all the constraints those program results provided.  The general composition of the Moon is very similar to the mantle of the Earth, suggesting some variant of the fission model might be the answer.  The problem with fission was its physical implausibility, as the early Earth was not like binary stars cited as analogs by the model’s proponents.  The near-identical oxygen isotopes of Earth and Moon indicated that co-accretion might be correct, but why would such planetary formation create two different objects (Earth and Moon) instead of a single body?  Capture was an attractive way of explaining the subtle differences between Earth and Moon, but not their similarities and it was not an easy model to reconcile dynamically with the Moon’s orbital properties.

The advent of the “Giant Impact” model of lunar origin supposedly severed this Gordian Knot of lunar origin.   Although first proposed in the mid-1970’s, it seemed to emerge fully grown from the forehead of Zeus at the 1985 Origin of the Moon conference in Kona, Hawaii.  In one fell swoop, the “big whack” explained all the salient features of the Earth-Moon system, including its oxygen isotopes (both Earth and proto-Moon formed at the same position near the Sun), its depletion in volatiles (such a large impact would vaporize the planets’ mantles and this material would be depleted in volatiles), and the high degree of angular momentum in the Earth-Moon system (an off-center impact would speed up the Earth’s rotation while the Moon was spun off into orbit around it).

Although many scientists embraced the Giant Impact model, a few dissidents remain.  Much of the model’s attraction stems from its apparent ability to explain any particular fact about or constraint on the Moon.  Lack of volatiles troubling?  No problem – the big whack would drive them away.  High spin rates on the early Earth?  The impact hit off-center.  Moon’s bulk composition like the Earth’s mantle?  The Moon came from the Earth’s mantle.  Is it too unlike the Earth’s mantle?  No problem – it comes mostly from the mantle of the (now destroyed) impactor planet.  In other words, the model is largely unconstrained and elastic enough to fit any fact or observation.

Scientists tend to be uncomfortable with such models; not only do they lack predictive power, they seem too much like “Just-So” stories.  However, finding something unexpected that matches the predictions of a model tend to give that model veracity and “completes” the jigsaw puzzle.  The new Spitzer findings might well be that missing piece of the puzzle.  They suggest that planetary collisions do happen (we didn’t really doubt that, but it’s nice to have a concrete example).  The presence of silicon monoxide gas indicates very high temperature, non-equillibrium processes – exactly what would be expected from a giant impact.

We may well find systems in various stages of evolution as we continue to observe the nearer stars and examine their planetary systems.  Having oither examples of multiple planetary systems allows us to “field check” our suppositions about the history of our own Solar System.  Some of the apparently contrived “Just So” stories may just be correct.

Lunch from the lunar dirt (Photo courtesy of Dr. Jeff Taylor, Univ. Hawaii)

We often hear the Moon described as a lifeless desert, a barren rock in space where nothing can survive.  Although the Moon is certainly different from the Earth, it is hardly barren.  From the 1970’s through the 1990’s (largely before we knew about the presence of water and other volatiles in the lunar polar regions) the late, lunar scientist Dr. Larry Haskin set forth some basic facts about the chemical composition of the Moon.  Larry was a chemist by training and his view was that the Moon has all that we need – just not in the form in which we need it.

Larry wrote a very interesting paper for the 1988 Second Symposium on Lunar Bases.  Over the years, I heard him give several different versions of this talk.  Initially, he called it “Wine and Cheese from the Lunar Desert” but after deciding that he didn’t want to drive away or offend any teetotalers in his audience, he changed it, first to “Cola and Cheese” and then “Water and Cheese from the Lunar Desert.”  Although the liquid varied, the cheese stayed.

Haskin’s argument is very simple.  Take a cubic volume of soil (about 1 meter in dimension) from anywhere on the Moon.  In that volume of soil (weight about 1600 kg), there is enough hydrogen, carbon, and nitrogen – the principal volatile elements implanted by the solar wind – to make lunch for two.  Larry’s menu was modest, but satisfying:  two cheese sandwiches, two glasses of wine (or cola, with real sugar), and two plums.  Chemical atoms needed to make up this meal are all present in that relatively small volume of soil; they are just not arranged in the form that we need them.  But the task is possible, given time and energy.

Because the Moon has no atmosphere and no global magnetic field, the highly energetic stream of particles from the Sun (the solar wind) implants its atoms directly onto the dust grains of the soil.  This material is mostly hydrogen and helium, but other light atoms such as carbon, nitrogen and other noble gases are also present.  These volatile elements seem to correlate with a property called “maturity” which means the amount of time a soil has been exposed to the space environment.  The amount of solar wind gas also correlates inversely with grain size – the finest fraction of the soil contains the most solar wind.  Another unusual correlation is with titanium; the highest quantities of solar wind hydrogen are found in very high titanium soils.  It’s not clear why this should be true, although it is postulated that the crystal structure of ilmenite (an iron- and titanium-oxide mineral) acts as a “sponge” for solar wind atoms.

Given these properties, the best soil on the Moon to process and extract these important volatile substances would be very fine-grained, high-titanium soils.  In fact, this soil occurs as the dark pyroclastic ash that sometimes covers mare and highlands areas on the Moon.  They are very fine-grained (typical mean grain sizes of a few tens of microns) and some are rich in titanium.  The tiny black glass beads returned by the Apollo 17 mission have up to 13 wt.% titanium dioxide (among the highest found on the Moon).  However, these Apollo 17 samples were buried by a landslide for millions of years so we do not know how much volatile material a mature, exposed surface ash deposit might contain.  A robotic mission to such an area to measure the amount of solar wind gas could answer these questions.

Extracting the volatiles from soil is very simple: just heat the soil to about 700° C.  Although simple in concept, in practice this may be a very difficult job.  We need to find a way to process the lunar soil in a continuous stream.  Batch processing is much less efficient and expensive.  Soil roasters that continuously roam the surface, heating the soil using solar thermal power and collecting and storing the emitted gas, is likely to be at least part of the ultimate solution.

During recent discussions about using lunar polar ice, some expressed concern that we would too rapidly devour what they perceive to be a limited resource.  Although the Moon has hundreds of millions of tones of water around the poles, ultimately, we will need to learn how to use the lower grade ore present elsewhere around the globe.  In this case, it will be the bountiful lunar regolith – the meters-thick outer layer of the Moon.  This resource can truly last a lifetime – the lifetime of humanity in space.  Wine and cheese (or beer or cola and cheese, if you prefer) is there for the taking and the making.  We are limited not by the intrinsic resources of the Moon but only by our own imaginations.

Something else to be thankful for this season—a Moon that has what we need to survive and thrive in space.

An ice rainbow seen in cirrus clouds on Earth. (UCSB Dept. Geography)

Five weeks ago a crater from the LCROSS impact formed on the Moon.  The pre-impact build-up had been sensational, but the actual event was largely invisible to observers on Earth. It was a different story on the Moon.  The slowly growing impact ejecta curtain threw water ice particles and vapor far out into space.  When the crater formed, flying ice particles could have refracted the glare of unfiltered sunlight into an “ice rainbow,” similar to those seen through very high altitude clouds on Earth.  For a very brief time, a rainbow might have been visible to an observer standing on the lunar surface.  And like its namesake, this rainbow is a promise – a promise that the Moon is habitable.  It is an invitation to humanity to extend man’s domain to our nearest planetary neighbor.

The LCROSS science team’s initial analysis of ejected impact plume data found evidence for water.  It appears that several other species, particularly some carbon substances also found in the cores of comets, may be present.  The new results suggest that some lunar polar volatiles may have their origins from outside the Moon, deposited there over millions of years by the impact of comets and asteroids.

Over the last 50 years, the idea of water ice at the lunar poles has generated as much angst as excitement within the scientific community.  Ice on the Moon was suggested by Watson, Murray and Brown in 1960.  They recognized that, regardless of the fate of such substances elsewhere on the Moon, the dark, cold floors of polar craters might retain volatile substances.  Rock and soil samples returned by the Apollo missions were not only bone-dry, but crystallized in a very reducing environment, suggesting that any indigenous lunar water, if present, must have been a very minor component.  Apollo scientist Jim Arnold resurrected the Watson et al. hypothesis forty years ago, concluding that their original proposal of water ice at the poles was still feasible and that a polar lunar orbiter was needed to search for such deposits.

We know that over geologic time, the Moon was bombarded by water-bearing objects.  Meteorites contain water, and just as they’ve landed on Earth, they’ve also hit the Moon.  Moreover, we’ve detected water vapor in the tails of comets with Earth-based telescopes.  But it was widely speculated that all this water must be lost from the Moon, which left the issue of polar ice unresolved.

Fifteen years ago, the 1994 Clementine orbiter mission revived our interest in the Moon’s polar regions.  When Clementine’s images of the Moon’s poles revealed large areas of shadowed terrain, it reminded Gene Shoemaker and the science team of the Watson and Arnold papers.  Large shadowed areas suggested that polar cold traps might really exist, so an experiment was improvised using the spacecraft transmitter to beam RF energy into the shadowed areas.  Analysis of the radio echoes suggested the presence of ice in shadowed areas near the south pole.  This result was questioned, largely because our team couldn’t repeat the passes using the improvised experiment.

In 1998, Lunar Prospector found evidence for excess hydrogen in the surface soils of both lunar poles.  These data could not show what form the hydrogen was in and had very low spatial resolution.  The issue, as to whether the observed polar hydrogen represented water ice in the dark cold traps or elemental hydrogen implanted by solar wind protons, was vigorously debated.  The preponderance of evidence in the years since Lunar Prospector, suggests that water ice is present in the polar areas, but its form, distribution and physical state are completely unknown.

The current flotilla of lunar orbiting spacecraft carry several advanced sensors, all designed to better characterize the environment and deposits of the polar regions of the Moon.  We have seen extremely low temperatures in the polar dark regions using the DIVINER instrument on the American Lunar Reconnaissance Orbiter (LRO) spacecraft.  The Japanese Kaguya mission mapped the topography and terrain of the polar areas and showed us the extent of the shadowed areas.  The Indian Chandryaan mission sent a probe into the south pole, mapped the extent of sunlight and carried two NASA instruments – the Moon Mineralogy Mapper (M3) and Mini-SAR radar.  In September, the M3 instrument found significant amounts of water bound into mineral structures at high latitudes.  The Mini-SAR instrument has made maps showing the interior of dark polar craters.  These maps are being analyzed for scattering characteristics to determine whether water ice might be present there; our initial results will be announced soon.

Now, the LCROSS impactor – sent to kick up the dust of the polar dark regions – has shown us that water ice does exist there.  We still don’t know how much water ice in total may be present; from Clementine,  we estimated there are billions of metric tones of water ice present in the south polar area.  Complete analysis of all of the remote sensing information in the next couple of years will ultimately give us a good estimate of the total amount of water available.  Clementine also revealed peaks of near-permanent sunlight in proximity to regions of permanent darkness at the poles (where the sun’s circular rotation keeps temperatures benign).

If you don’t know where you’re going, any path will get you there.

The Moon has the resources needed to bootstrap a sustained, permanent human presence.  It is the place where we can learn how to live and work productively in space.  The Moon has put out a welcome mat.  What are we waiting for?

Collapse breccia near a lava tube entrance (Photo by Dr. Harmon Maher, Univ. Nebraska)

The science team of the Japanese Kaguya mission have just published a paper claiming to have found an opening to a cave on the Moon.  Such a discovery is a potentially important development for future lunar habitation.  Lava tubes are large caves created during the volcanic eruption of a very fluid, highly effusive lava.  They are common on Earth, especially in iron-rich basaltic lavas, such as those that make up most of the Hawaiian islands.

The idea that caves occur on the Moon has been around for a long time.  We have long known that the lunar maria (the dark, smooth, relatively uncratered plains of the Moon) are made up of old basaltic lava flows.  Looking at orbital photographs, we find many narrow, winding channels (or rilles) in the maria.  These channels cannot be the product of water erosion, as flowing liquid water cannot exist in the vacuum of the lunar surface.  So workers looked for another explanation.  They found it in lava channels and tubes.

On Earth, volcanic terrains often show small channels within young lava flows.  Lava tubes form when hot lava erupts, pouring out onto the surface.  The lava immediately begins to cool, with the outermost edges cooling first.  As the lava cools and hardens from the outside edges inward, the flow of still-molten lava becomes constricted to a central, narrow, interior conduit.  When the eruption stops, the still-liquid lava drains out, leaving behind an empty cave-like tube-shaped segment.  In some instances, the roof of the drained tube collapses, exposing the tube interior as a channel or, if less extensive, creating a “skylight” or a hole that allows access to the cave interior.  Lava caves are quite common on volcanoes made up of runny (low viscosity) lava, such as the shield volcanoes of Hawaii.

Caves found on the Moon would be very useful.  Because they form in dense basaltic lava, the space inside a tube is protected from both the hard radiation of the lunar surface and the constant micrometeorite bombardment the Moon experiences.  Moreover, the temperature of the subsurface of the Moon is very stable; below the zone which experiences the extreme temperatures of night and day, lunar temperatures are fairly constant at about -20° C.  On Earth, lava caves can be quite roomy, with diameters tens of meters across and hundreds of meters long.  On the Moon, these dimensions may be much larger – the low gravity of the Moon results in much bigger lunar lava tubes and channels than their terrestrial counterparts, being hundreds of meters across and many kilometers long.  Thus, they offer many potential advantages to future lunar inhabitants.

Before we pack our bags for the Marius Hills, we should take note of some other properties of lava tubes.  Many lava tubes partly or completely collapse immediately after their formation.  If the roofed segments are weakened by flowing lava, earthquakes, or are very thin, they cannot support their own weight and after the lava drains out, the roof falls into the void.  This is seen on both the Earth and Moon.  Hadley Rille, visited by the Apollo 15 astronauts in 1971, is a lava channel, parts of which were roofed over as a tube.  The crew landed near a channel portion, but a roofed segment is only about 12 km from the site.  High resolution images of that segment show no entrance to an underground cave there or elsewhere along the rille (channel).  That doesn’t mean that there is no cave portion of Hadley Rille, but it does suggest there is no entrance to a cave there.

Other candidates on the Moon look more promising.  Numerous lava tube “skylights” have been noted in association with many lava channels on the Moon.  These skylights are typically unconnected to each other or any nearby feature and are found as individual tube segments that appear to start and stop along the trend of a rille.  It is impossible to identify lava cave entrances because most of the images we have for these features are low resolution and have near-vertical viewing geometry.

The new Kaguya pictures show a circular, rimless pit on the floor of the projected segment of a rille.  Collapse pits are not uncommon on the Moon and many of them are not associated with lava channels or tubes.  So while the new Kaguya images are intriguing, they are not definitive evidence for a cave.

There are other issues in regard to the use of lunar lava tubes.  Many (if not most) terrestrial lava tubes are not void; they are either filled with late-stage lava, which plugs up the cave, or by collapse debris, which buries it.  Finding a new void lava tube is celebrated by the caving community simply because void tubes are rare.  But even if a void tube formed on the Moon, it may not remain that way for all time.  Lunar volcanism was active over 3 billion years ago.  Since then the Moon has been constantly bombarded by debris, initiating landslides, infilling craters, and generating seismic waves.  Such a bombardment could well act as a leveler to collapse and fill in void lava caves that might have existed on the Moon.

But the biggest problem with lunar caves is even more fundamental – they aren’t where we want them.  Sustained human presence on the Moon is enabled by the presence of the material and energy resources needed to support human life and operations around the Moon.  After over a decade of study and exploration, we now know that these locations are near the poles of the Moon.  Unfortunately, both poles are in the highlands and finding a lava tube in such non-volcanic terrain is highly unlikely, regardless of the imaginative ramblings of certain science-fiction authors.  If a lunar cave were present there, we would certainly consider using it.  But it makes no more sense to locate a lunar base near the caves, than it does to build a water-park in the Sahara desert.

The formation of lunar lava tubes and caves is an interesting scientific topic, but their utilitarian value is uncertain, at least until we have established a permanent presence on the Moon.  Ultimately, we may be able to use them to live on the Moon, but first, we need to follow the Willie Sutton principle and go where the money is.