Shackleton crater, Moon. Clockwise from top left: topography from laser altimetry, image from SMART-1 mission, lighting map (brighter is longer periods of illumination) from the LRO Camera, Mini-RF CPR image draped over shaded relief map. The crater is about 20 km in diameter.

Though unremarkable in appearance compared to the roughly 4,000 craters on the Moon in its size range, the 20 km diameter crater Shackleton has been the source of relentless scientific controversy for the past 20 years.  Shackleton is located at the south pole of the Moon; indeed, its near side rim is the precise location of the geographic pole itself.   Its location makes observation by Earth-based telescopes difficult and it was not well photographed by the Lunar Orbiter series (our principal source of lunar images) of the 1960s.  That all changed in 1994 with the flight of the joint DoD-NASA mission to the Moon, Clementine.

Clementine carried cameras that globally imaged the Moon in eleven visible and near-infrared wavelengths.  In addition, it mapped the surface and lighting of the poles of the Moon at uniform resolution over the course of almost three lunar days (74 Earth days).  When the Science Team first saw the south polar mosaic, the extent of darkness in the map was striking.  Because the Moon’s spin axis is close to perpendicular to the ecliptic plane, the Sun is always at the horizon at the lunar poles.  Instead of rising and setting, the Sun circles around the poles at or near the horizon.  Because of this grazing incidence, an area in a topographic depression may be in permanent shadow.  And so it appeared for Shackleton crater in the Clementine data, setting off bells in the heads of the Science Team.

A key controversy of the post-Apollo era was whether the lunar poles might contain water or not.  Although the Apollo samples had been studied and found to be “bone-dry,” we had not been to the poles on any Apollo mission.  We knew that any shadowed areas had to be extremely cold as well as permanently dark.  As water-bearing debris in the form of asteroids and comets constantly strike the Moon, it was thought that some of that water might get into a polar “cold trap” and would be kept there (essentially) forever – billions of years of impacting cosmic “debris” can add up.

Clementine was not configured to measure the presence of water, but a cleverly improvised experiment used the spacecraft’s data transmitter to beam radio waves into the dark regions near the poles and listen to their reflected echoes on the enormous (70 m) dish antenna of NASA’s Deep Space Network.  Interestingly, the reflections indicated an enhancement of “same sense” polarization within the (very large) resolution cell that contained Shackleton crater.  A collect of data from a nearby sunlit area (taken as an experimental control) did not show this peak.  The Clementine team interpreted the RF peak as evidence for the presence of a few percent water ice within the dark, cold interior of Shackleton crater.  The media quickly spread the startling news about water on our “bone-dry” Moon.

Such a controversial conclusion did not go unchallenged.  Some in the radar community argued that abundant wavelength-sized rocks on the surface were the source of the enhanced same sense reflection.  Since the lunar surface is indeed rocky, this interpretation could not be ruled out.  Then a few years later, the Lunar Prospector (LP) mission found an enhancement of hydrogen concentration at both poles of the Moon; as hydrogen is a major constituent of water, the idea ice exists in the dark areas gained credence and has lead to a decade-long scientific search (using a variety of techniques) for lunar polar ice.  Though many areas near the poles were studied in detail, attention continued to be drawn back to Shackleton and the area near the south pole.

From studying Clementine images, we discovered that part of the rim crest of Shackleton is one of the most sunlit areas on the Moon.  Now we had a double-attraction: constant sunlight with water ice nearby.  At a press briefing in 1996, I called this area of water and sunlight “the most valuable piece of real estate in the Solar System.” Nothing found subsequently has changed my mind on that judgment.

So what have we learned about Shackleton lately?  Many different, new sensors have flown to the Moon in the last few years, including radar, ultraviolet (UV) imaging, laser reflections, and low-light level imaging.  And yet again, Shackleton crater continues to confound us with contradictory evidence, both for and against the presence of water ice in its interior.

In 2009, the question regarding the presence of water ice somewhere near the lunar south pole was answered when the LCROSS impactor threw up a cloud of water vapor and ice particles during its collision with the floor of the nearby crater Cabaeus.  Spectral mapping instruments on three different spacecraft (Chandrayaan-1, Cassini, and EPOXI) documented the presence of adsorbed water on the lunar surface, increasing in concentration with latitude toward both poles.  A small impact probe flown by India (MIP) passed through a water vapor zone in the exosphere just above the lunar south pole.  And radar images from Mini-RF, our radar imaging experiment on both Chandrayaan-1 and Lunar Reconnaissance Orbiter (LRO), found evidence of high same sense reflections (just as Clementine had suggested in 1994) within the interior of Shackleton crater.  These new lines of supporting evidence were countered by Japanese researchers, whose Kaguya spacecraft imaged the interior of the crater and found morphology similar to other lunar craters in the same size-class.  But no one had ever claimed that the interior of Shackleton was a skating rink of pure ice – the lunar polar ice is partly covered by waterless dust and mixed with an unknown amount of dry regolith.

Interpretation of the new data continues to vex us.  The LOLA (laser altimeter) team on LRO recently published a paper that documents the high reflectivity (at 1 micron wavelength) of the walls of Shackleton.  Although the team’s favored interpretation is that this is caused by a constant exposure of fresh material on a steep slope, they also note that it is consistent with the presence of water ice on the walls of the crater.  In addition, a team analyzing neutron spectrometer data from both LP and LRO found evidence in the fast neutron data (never before analyzed) that water in the interior of Shackleton is a possible explanation for its signal.  Detailed analysis of the Mini-RF data for Shackleton corrected for its steep wall slopes and found that the presence of 5-10 wt.% water there provides the best model fit to the observed data.  Newly obtained UV images from LRO show the existence of water frost in the interiors of the craters Haworth and Shackleton, and the neutron detector on LRO shows enhanced hydrogen within both Shoemaker and Shackleton craters.  The Japanese team from Kaguya continue to insist that the no-ice interpretation is the correct one.

So we are left with a mystery.  Some evidence is pro-ice and some is contra-ice.  I find it interesting that for most of the investigators, new data does not necessarily change any minds, but tends to be interpreted in a way most favorable to their previously published ideas.  This should not be terribly surprising; the people who have argued for some specific interpretation presumably did so for good reasons and desire hard and clear-cut evidence to the contrary before abandoning a previously held position, one no doubt reached after much thought and soul-searching.

The way to unravel the water-ice mystery is to go to the surface of the lunar south pole (or both poles) and measure the composition of the surfaces in question.  Getting a definitive answer about the nature of lunar water would be game changing.   Some say the bigger mystery is:  Why hasn’t the United States sent a rover to the south pole of the Moon to take a closer look?

Composite image of the north pole of Mercury. Red are the areas of permanent shadow; yellow delineates radar bright deposits mapped from Earth. Data are plotted on a photomosaic of MESSENGER images. NASA

Mercury – the planet, not the element – was in the news this past week.  For some time, we had suspected that the poles of Mercury might harbor deposits of water ice.  This – on a planet so close to the Sun that the surface temperature at the equator is hot enough to melt lead!

Yet like the Moon, Mercury’s spin axis is perpendicular to the plane in which it orbits the Sun.  This means that large craters near Mercury’s poles lie in permanent shadow (“shivering” around -170° C), unaffected by the Sun’s searing heat (equivalent to more than eleven times the solar flux we get on Earth).  As on the Moon, these permanently shadowed areas get heat from only two sources – the 3 K background heat of space, created during the Big Bang some 15 billion years ago, and whatever heat is being generated now from the deep interior (a quantity that geophysicists call the heat flow of a planet).

Large planets (like Earth) generate heat mostly from the decay of radioactive elements deep inside them.  This heat is lost largely through the phenomenon of volcanism, in which melted rock from the interior is erupted onto a planet’s surface as lava and ash.  Smaller planets and moons likewise experience this heating and volcanism, but because they are have lower overall contents of heat-producing elements, their volcanic episodes occurred in the distant past.  Much of the heat of these smaller planets has been largely dissipated.  Thus, on Mercury, we suspect that the overall heat flow is very low, resulting in extremely cold temperatures on the floors of its permanently shaded polar craters.

For many years, astronomers have studied Mercury with radio telescopes from Earth (using radar to make images of its surface).  Because the orbital inclination of Mercury is relatively high (about 7°), we can get a fairly good look into the interiors of the polar craters.  Interestingly, even though Mercury is much farther away than the Moon, we can see more of the mercurian polar areas because of this relatively high orbital inclination (the Moon’s orbital plane is inclined only 5°).  These radar pictures showed an amazing and unexpected feature – the dark areas are filled with material that is highly reflective at radio frequencies, properties similar to the surfaces of the icy moons of Jupiter (Europa, Ganymede and Callisto).

These results were so unexpected and startling that debate raged for many years whether these deposits really were what they appeared to be: water ice.  Facts are stubborn things and few materials have radio properties similar to ice.  Some suggested that sulfur might be an alternative explanation, but provided little evidence for such behavior.  Moreover, another moon of Jupiter, Io, which has a surface largely composed of sulfur, does not show the radar brightness or “glint” seen on the other, ice-rich Jovian moons.

The debate on the nature of the Mercury polar deposits has now been settled with the release of new data from the MESSENGER mission.  Launched on August 3, 2004, with insertion into obit around the planet on March 18, 2011, the spacecraft has been taking pictures and making measurements of Mercury for the last two years.  We have mapped the extent of darkness near the poles, measured the temperatures of the surface inside these regions, and detected the presence of significant amounts of hydrogen there.  All of these results are strongly supportive of the water ice interpretation.

The existence of ice near the poles of Mercury supports the case for water ice on our own Moon, although there are some significant differences between the two occurrences.  Like Mercury, the Moon’s spin axis is nearly perpendicular to the plane of its orbit around the Sun.  The similarity of the terrain of both bodies results in deep holes that hide large expanses of terrain from the glare and heat of the Sun.  Both objects have been volcanically active in the past, but not today, meaning that the average rates of heat flow on both are low.  These properties result in the creation of polar “cold traps” in which any entering volatile substance (such as water molecules) cannot escape.

The solid bodies of the inner Solar System are constantly hit by debris from comets and asteroids.  This material contains water, both in free form and bound within hydrous minerals.  On smaller objects (like the Moon and Mercury), most of this water is lost to space, but we suspected that some of it might be retained within these dark cold traps near the poles.  Now we know that such a process does occur.

Differences between the Moon and Mercury result in differing amounts and settings for their polar deposits.  Being much closer to the Sun, one might expect Mercury to contain less water ice, but a variety of evidence suggests that the opposite is the case.  The polar ice of Mercury appears to be greater in extent and thickness than comparable deposits on the Moon.  This probably results from two factors.  First, Mercury is a bigger object, with a surface gravity about twice that of the Moon.  Thus, it is more difficult for water to “escape” from Mercury.  Second, the closeness of Mercury to the Sun (the edge of biggest gravity well of the Solar System) results in a higher flux of cometary impacts there than experienced in the Earth-Moon system.  So more water is being added to Mercury, where it is more easily retained.

Nonetheless, both Moon and Mercury have similar polar environments and processes.  The long debate – a scientific controversy for over 50 years – about water at the poles of these objects has been resolved.  The next steps will be to characterize these deposits in situ using a soft lander and selected instruments to measure the amounts, states and distributions of water in the polar areas.  Because of the great difficulty in even getting into orbit around Mercury (let alone landing there), doing this first on the Moon will mostly likely happen first.  So, here again is another rationale for sending a robotic surveying lander and rover mission to the poles of the Moon – in addition to characterizing these areas for our future presence there, by inference, we will also learn about the polar processes on and environment of Mercury.

A planetary “two-fer.”  Let’s get on with it.

Future industrial activity on the Moon -- science fiction? (Artwork by Pat Rawlings)

Space missions are commonly thought of as the ultimate in “high tech.”  After all, rockets blast off into the wild blue yonder, accelerate their payloads to hypersonic and orbital speeds and then operate in zero gravity in the ice-cold, black sky of space.  It requires our best technology to pull off this modern miracle and even then, things can go wrong.  Why would anyone believe that with high technology, sometimes less can be more – that we’re missing a bet by not utilizing current technology.   Like the intellectual tug of war involving man vs. machine, there also is a tug of war between proven technology and high-tech.  Creating these barriers and distinctions is nonsensical.  We need it all.  And we can have it all.

Point in question – in situ resource utilization (ISRU), which is the general term given to the concept of learning how to use the materials and energy we find in space.  The idea of learning how to “live off the land” in space has been around for a long, long time.  Countless papers have been written discussing the theory and practice of this operational approach.  Yet to date, the only resource we have actually used in space is the conversion of sunlight into electricity via arrays of photovoltaic cells.  Such power generation is clearly “mature” from a technical viewpoint, but it had to be demonstrated in actual spaceflight before it became considered as such (the earliest satellites were powered by batteries).

The reason we have not used ISRU is because we’ve spent the last 30 years in low Earth orbit, without access to the material resources of space.  Many ideas have been proposed to use the material resources of the Moon.  A big advantage of doing so is that much less mass needs to be transported from Earth.  The propellant needed to transport a unit of mass from the Earth to the Moon keeps us hobbled to the tyranny of the rocket equation – a constant roadblock to progress.  If it takes several thousand dollars to launch one pound into Earth orbit, multiply that amount times ten to get the cost to put a pound of mass on the Moon.

In the space business, new technologies tend to be viewed with a jaundiced eye.  Aerospace engineers in particular are typically very conservative when it comes to integrating new technology into spacecraft and mission designs, largely on the basis that if we are not careful, missions can fail in a spectacularly dreadful fashion.  To determine if a technology is ready for prime time, NASA developed the Technology Readiness Level (TRL) scale, a nine-step list of criteria that managers use to evaluate and classify how mature a technical concept is and whether the new technology is mission ready.

Resource utilization has a very low TRL level – usually TRL 4 or lower.  Thus, many engineers don’t think of ISRU as a viable technique to implement on a real mission.  It seems too “far out” (more science fiction than science).  Believing that a technology is too immature for use can become a self-fulfilling prophecy, a “Catch-22” for spaceflight:  a technology is too immature for flight because it’s never flown and it’s never flown because it’s too immature.  This prejudice is widespread among many “old hands” in the space business, who wield TRL quite effectively in order to keep new and innovative ideas stuffed in the closet and off flight manifests.

In truth, the idea that the processing and use of off-planet resources is “high technology” is exactly backwards – most of the ideas proposed for ISRU are some of the simplest and oldest technologies known to man.  One of the first ideas advanced for using resources on the Moon involve building things out of bulk regolith  (rocks and soil of the lunar surface).  This is certainly not high-tech; the use of building aggregate dates back to ancient times, reaching a high level of sophistication under the Romans, who over 2000 years ago built what is still the largest free-supported concrete dome in the world (the Pantheon).  The Coliseum was made of concrete faced by marble.  The Romans also built a complex network of roads, some which remain in use to this day; paving and grading is one of the oldest and most straightforward technologies known.  Odd as it may seem, sand and gravel building material is the largest source of wealth from a terrestrial resource – the biggest economic material resource on Earth.

Recently, interest has focused on the harvesting and use of water, found as ice deposits, at the poles of the Moon.  Digging up ice-laden soil and heating it to extract water is very old, dating back to at least prehistoric times.  This water could contain other substances, including possibly toxic amounts of some exotic elements, such as silver and mercury.  No problem – we understand fractional distillation, a medieval separation technique based on the differing boiling temperatures of various substances.  Again, this concept is not particularly high-tech as only a heater and a cooling column is needed (basically the configuration of an oil refinery).  Some workers have suggested that lunar regolith could be mined for metals, which can then be used to manufacture both large construction pieces and complex equipment.  Extracting metal from rocks and minerals is likewise very old, developed by the ancients and simply improved in efficiency over time.  Processes like carbothermal reduction have been used for hundreds of years. The reactions and yields are well known, and the machinery needed to create a processing stream is simple and easy to operate.

In short, the means needed to extract and use the material wealth of the Moon and other extraterrestrial bodies is technology that is centuries old.  Even advanced chemical processing was largely completely developed by the 19^th Century in both Europe and America.  The “new” aspects of ISRU technology revolve around the use of computers to control and regulate the processing stream.  Such control is already used in many industries on Earth, including the new and potentially revolutionary technique of three-dimensional printing.  A key aspect of the old “Faster-Cheaper-Better” idea (one NASA never really embraced) was to push the envelope by relying more on “off-the-wall” ideas, whereby more innovation on more flights would lead to greater capability over time.

Nothing that we plan to do on the Moon involves magic, alchemy or extremely high technology.  Like most new fields of endeavor, we can start small and build capability over time.  The TRL concept was designed as a guideline.  It was not intended as a weapon eliminating possibly game-changing techniques from consideration or to carve out funding territories.  Attitudes toward TRL must change at all levels, from the lowly subsystem to the complete, end-to-end architectural plan.  A critical first step toward true space utilization and for understanding and controlling our destiny there is to recognize and take advantage of the leverage one gets from lunar (and in time planetary) resource utilization.

The Sun exudes a constant stream of hydrogen, called the "solar wind."

New data returned from a fleet of orbiting satellites changes our perceptions of the history and processes of the Moon.  Concentrated at both lunar poles, and to date the most striking discovery, is the documentation of the presence of large amounts of water.  Though this water has been confirmed by several differing techniques (from multiple missions), we remain uncertain about its source.  Two principal origins have been proposed: 1) water added by the in-fall of water-bearing meteorites and comets during the impact bombardment of the Moon; and 2) the manufacture of water from hydrogen implanted in the lunar soil by the wind from the Sun.

A recent discovery may shed some new light on the origin of lunar water.  Researchers conducting detailed examination of tiny fragments of glass in soil returned by the Apollo astronauts found the molecule hydroxyl (OH) present in the glass.  Interestingly, the isotopic composition of these OH molecules indicates the bulk of the hydrogen comes from the Sun, not from cometary and asteroidal impacts.

The Moon has no atmosphere and no global magnetic field.  As a result, the solar wind – the stream of atoms and molecules constantly emitted by the Sun – directly impinges upon the lunar surface.  Most of this solar wind consists of hydrogen, either in the form of neutral atoms or positively charged ions (i.e., protons).   After it encounters the Moon, this spray of hydrogen has a complex fate, with at least some of it being implanted into the lunar dust.  In a process called adsorption, many of the hydrogen atoms stick to the surfaces of the dust grains.  The amount of adsorbed hydrogen varies by position and chemical composition around the Moon, but it can be present in quantities ranging from less than 10 to over 100 parts per million (ppm).

Impact glass is a major component of lunar regolith – up to 60% by weight of the soil at some landing sites.  The constant bombardment of the lunar surface by microscopic meteorites crushes and grinds up the surface rock, continually mixing the outer layer of the Moon.  When a micrometeorite strikes a rock, it forms a micro-crater (wholly melting the surface beneath this pit) and creates a clear, chemically homogeneous glass particle.  However, when a micrometeorite strikes lunar soil instead of rock, its energy is converted mostly into heat.  This flash heating creates a mixture of melt and mineral debris called agglutinate glass.

The new work details results of analyses of agglutinates returned from several lunar landing sites.  Their study measured both the amounts of hydroxyl present and its isotopic composition.  A normal atom of hydrogen is a single proton and an electron.  But in a rare form of hydrogen, called deuterium, the nucleus contains both a proton and a neutron.  The ratio of this form of “heavy hydrogen” to “normal” hydrogen is unique for different materials throughout the Solar System.  By tracking the D/H ratio in the sample, one can assign a source origin to the measured hydrogen.

When the lunar agglutinate glasses were studied, it was found that their D/H ratios indicated that most of the hydrogen in the hydroxyl molecules came from the Sun and not from cometary or meteoritic sources.  However, the source of the hydrogen is not completely solar, as the D/H ratios suggest some mixing with a subordinate component of either lunar or cometary origin.  The authors of this study suggest that the hydroxyl found on the Moon was created when a small impact flash heated the soil, releasing the adsorbed hydrogen and chemically reducing the metallic oxides in the soil into native metal (found as extremely tiny grains on the surfaces of the agglutinates) and hydroxyl molecules.  Multiplied by billions, such a process could account for the generation of water on the lunar surface.  Subsequent migration of these molecules toward cooler-than-average areas of the Moon (i.e., the higher latitudes, up to and including the poles) may have created the polar ice deposits found by numerous techniques.  In the view of the authors of this study, lunar water comes mostly (but not entirely) from the Sun.  This constant process, occurring on the sunlit hemisphere of the Moon, could create an enormous reservoir of hydroxyl molecules (in motion due to their thermal instability), slowly but constantly moving toward the poles.

If such a process occurs on the Moon, one might expect the accumulation of water in every location where water is stable (i.e., within every permanently dark and cold region near both poles).  But it appears that ice at the poles is not uniformly distributed, occurring in high concentration in some areas while absent in others.  This pattern suggests that the source of polar water might be controlled by a non-equillibrium process, such as episodic bombardment by asteroids and comets.  In fact, both solar wind-produced and cometary water may be present at the poles, but until the ice there is actually analyzed for its D/H content, we cannot be certain of its origin.  Such a measurement does not require the return of a polar ice sample to the Earth.  It could be made remotely in situ on the Moon with a properly instrumented robotic spacecraft.

It is important to emphasize that although the quantities of water generated by this process are potentially very large, the hydroxyl in agglutinate glass should not be considered an economic resource.  These molecules occur globally but at very low levels of concentration (tens of ppm).  Even if this water is the primary and ultimate source reservoir of lunar water, the migration of the molecules and their subsequent collection by the cold traps near the poles serve as a concentrating mechanism, where ice accumulates in large quantities, confined within small areas — the classic definition of an ore body.

What a change has occured in the mindset the lunar science community in the past few years!  From a bone-dry lump of rock in space to a complex, still mysterious body with a dynamic hydrological cycle.  It’s clear that many more discoveries about our Moon and its resources have yet to be revealed.  The more we learn about the Moon, the greater the range of processes we must account for and the more subtle and complex its history becomes.

"True" color (left) and "false" color (right) images of the near side of the Moon from Clementine. "Blue" units in Mare Tranquillitatis (right middle of false color image) are ilmenite-rich lavas.

The color of the Moon has been studied for years.  Lunar color is a subtle, yet fascinating phenomenon.  Just when it seemed that we had an explanation, complications would arise.  We now think we have a reasonable explanation for it.  So, why is the Moon gray?  Or to ask the question “scientifically”— What factors account for the range of spectral reflectance seen on the Moon?

Early Apollo astronauts were very impressed with the Moon’s lack of color.  During Apollo 8 (first mission to orbit the Moon in 1968) Jim Lovell remarked, “The Moon is basically gray – no color.”   The Apollo 10 crew was struck by the numerous brownish hues exhibited by the Moon – from a bright tan to a dark, chocolate brown.  When the first astronauts landed and walked on the Moon (Apollo 11), they had an even closer view.  Buzz Aldrin mentioned that although the surface color was basically gray, he could see interesting colors within some rocks outside the LM window.  During the EVA, Aldrin mentioned to Neil Armstrong that he had seen “some purple rocks.”  Purple? — perhaps so.

The Apollo 15 crew was surprised on their 1971 mission to catch a fleeting glimpse of green on the surface (in film shot earlier by crews on the lunar surface, color was too subtle to be seen). When they raised the sun visors of their helmets to again see that the soil was gray, the disappointment in their voices was palpable.  But then, at the very next station, they again saw a flash of green and this time, it was still green when the visors were raised.  Despite the predictable remarks about “green cheese,” this lunar material – consisting of volcanic glass erupted from deep (> 400 km depth) within the Moon under high pressure – was still green when brought back to Earth.

During their second lunar traverse in 1972, the crew of Apollo 17 found orange soil at Shorty crater.  Also volcanic glass, this soil is made up of tiny (~50 micron) beads of orange glass, again erupted from great depth.  It is orange (as opposed to the Apollo 15 green glass) because of its relatively high titanium content.  It is mixed with black glass beads, of identical composition, but in this case, partly crystallized.  Subsequent study of the Apollo samples have found volcanic glass fragments in almost every color in the spectrum, from red to yellow and brown in addition to the two described above.

True colors of some selected lunar samples. Top left - green glass pyroclastics from the Apollo 15 landing site. Top right - orange and black glass from Apollo 17. Bottom left -- troctolite showing yellow-brown olivine crystals. Bottom right - brownish crystals of orthopyroxene in Apollo 17 norite sample.

At this point, it is tempting to ascribe lunar color seen at a distance to the intimate mixing of a variety of colors present at fine scale.  But this is not quite correct.  Most returned lunar samples are also gray, ranging from a very dark charcoal to a light, almost white-gray shade.  Minor variations can be seen as a result of the presence of certain minerals.  In particular, the mineral olivine (an Mg- and Fe-rich silicate) is abundant in the lunar crust and is often green or a brownish yellow.  Ilmenite (and iron- and titanium oxide) is bluish-black and probably the source of the  “purple” Aldrin saw in some rocks during the Apollo 11 EVA.  Moreover, the astronauts could sometimes see significant color units from space.  After his surface visit, Apollo 17 astronaut Jack Schmitt (in orbit) saw orange material, excavated by small craters on the southwestern rim of the Serenitatis basin.  He suggested that this material might be related to the orange soil collected at the landing site a few days earlier.

Interestingly, one can detect subtle color differences on the Moon with telescopes and from spacecraft.  Although the Moon appears gray at first glance, one notices different hues of gray in certain places.  The dark Mare Tranquillitatis on the eastern near side is a noticeably darker and “bluish-gray” compared to the dark mare plains just to the north in Mare Serenitatis.  Part of the reason the Moon looks whitish-gray in the sky can be attributed to the fact that it is the brightest object in the night sky – dazzling the eye when first looked at (either with your naked eye or through a telescope).  Spacecraft views also reveal color differences.  It is common practice for lunar scientists to work with “false color” composite images, where color variations are “stretched” to extreme degrees to exaggerate differences in order to make them easier to work with.  The typical “false color” version of the near side of the Moon shows brilliantly colored “blue” and “red” maria; these color units do not coincide with mare-highland boundaries.  The received wisdom is that the different color units in the lunar maria represent lava flows of differing composition. That some lavas are enriched in titanium was a major finding from the Apollo sample studies.  Interestingly, these high-titanium lavas come from “blue” regions in the maria.  Initially, this was only an empirical correlation but we now know that it is the presence of ilmenite (the iron-, titanium-rich oxide) in these basalts that makes them “blue.”

It should be noted that color differences on the Moon are extremely subtle, requiring intensive image processing to display them clearly.  Typically, color differences on the Moon are less than about one percent or so.  We are able to see these differences with a careful look, but mapping the detailed boundaries of individual lava flows requires image processing to make the “false color” composites.

Lunar soil from the Apollo 11 landing site. Mostly gray, the fine material shows splashes of colors, including green, red and brown. Image by Randy Korotev, Washington Univ.

The “true” color of the Moon is a brownish (i.e., reddish) gray, but overall, the surface is fairly neutral in tone.  If the Earth had no atmosphere, hydrosphere or biosphere, it too would be largely a brownish-gray, as its crust is made up (more or less) of the same silicate and oxide minerals as the Moon (in slightly different proportions).  It is the weathering effects of air and water and biological activity at the Earth’s surface that makes it so colorful.  The Moon – having none of these processes – displays the “true color” of the rocky planets of the Solar System.  The dominant mineral in the lunar crust is plagioclase, a calcium/aluminum-rich silicate mineral.  Plagioclase is gray.  Thus, the dusty surface of the Moon, derived from plagioclase-rich rocks, is likewise gray.  When we talk about “red” and “blue” in lunar terms (as in “blue mare basalts”), we mean bluer, or less reddish, than comparable mare deposits elsewhere on the Moon.  So in reality, lunar color differences are really just varying degrees of reddish gray, some more so than others.

And what of the blue Moon?  As Conan the Barbarian might say, “But that is another story…..”

Enterprise in space: Free markets or government subsidies?

Free Enterprise:  Business governed by the laws of supply and demand, not restrained by government interference, regulation or subsidy – also called free market.

Rick Tumlinson of the Space Frontier Foundation published a “free-enterprise” critique of the Republican platform in regard to the American civil space program. Indeed, the text of the space plank is vague (no doubt intentionally, so as to give the candidate maximum flexibility to structure the space program to align with his vision and goals for the country).  But what I found most interesting was the underlying premise and assumptions in Tumlinson’s article, a worldview that I find striking.

In brief, Tumlinson approves of the current administration’s direction for our civil space program.  The U.S. has stepped back from pushing toward the Moon, Mars and beyond and redirected NASA on a quest for “game-changing” technologies (to make spaceflight easier and less costly), while simultaneously transitioning launch to low Earth orbit (LEO) operations to private “commercial space” companies selected by our government to compete for research and development funding and contracts.  Many see this as gutting NASA and the U.S. national space program.  To be clear, the term “commercial space” in this context does not refer to the long-established commercial aerospace industry (e.g., Lockheed-Martin, Boeing) but to a collection of startup companies dubbed “New Space” (typically, companies founded by internet billionaires who have spoken much and often about lofty space plans, but have actually flown in space very little).

Tumlinson criticizes the Republican space plank because it does not explicitly declare that a new administration would continue the current policy.  In his view, the very idea of a federal government space program, including a NASA-developed and operated launch and flight system, is a throwback to 1960’s Cold War thinking.  Instead, he envisions space as a field for new, flexible and innovative companies, untainted by stodgy engineering traditions or bloated bureaucracy.  Many space advocates on the web hold this viewpoint – “If only government would get out of the way and give New Space a chance, there will be a renaissance in space travel!”  But travel to where?  And why?

The idea that LEO flight operations should be transitioned to the commercial sector is not new.  It was a recommendation of the 2004 Aldridge Commission report on implementing the Vision for Space Exploration (VSE).  NASA itself started the Commercial Orbital Transportation Services program (COTS) in 2006, designed to nurture a nascent spaceflight industry by offering subsidies to companies to develop and fly vehicles that could provision and exchange crew aboard the International Space Station.  That effort was envisioned as an adjunct to – not a replacement of – federal government spaceflight capability.

The termination of the VSE and the announcement of the “new direction” in space received high cover from the 2009 Augustine committee report, which concluded that the current “program of record” (e.g., Constellation) was unaffordable.  The Augustine Committee received presentations with options to reconfigure Constellation whereby America could have returned to the Moon (to learn how to use resources found in space) under the existing budgetary cap, but they elected to start from first principles.  Hence, we have something called Flexible Path, which doesn’t set a destination or a mission but calls on us “to develop technology” to go anywhere (unspecified) sometime in the future (also unspecified).  With target dates of 2025 for a “possible” human mission to a near-Earth asteroid and a trip to Mars “sometime in the 2030’s,” timelines and milestones for the Flexible Path offer no clarity or purpose.  Try getting a loan or finding investors using a “flexible” business plan.

Tumlinson argues that both political parties should embrace this new direction because New Space will create greater capability for lower cost sooner.  He also makes much about the philosophical inclinations of the Republican Party (the “conservative” major party in American politics) – Why don’t the Republicans support free enterprise in space?  Why are they putting obstacles in the way of all these new trailblazing entrepreneurs?  As to those obstacles, it is unclear exactly what they are.  True enough, there are regulatory and liability issues with private launch services, but not of such magnitude that they cannot be handled through the traditional means of indemnification (e.g., launch insurance).

The COTS program record of the past decade largely has not been a contract let for services, but a government grant for the technical development of launch vehicles and spacecraft.   Close reading reveals the real issue:  Tumlinson wants more of NASA’s shrinking budget to finance New Space companies. He is concerned that a new administration might cut off this flow of funding.  However, what will cut off the flow of funding is having no market, no direction, and no architectural commitment – regardless of who occupies the White House.

The belief of many New Space advocates is that once they are established to supply and crew the ISS, abundant and robust private commercial markets will emerge for their transportation services.  Although many possible services are envisioned, space tourism is the activity most often mentioned.  Whether such a market emerges is problematic.  Although Richard Branson’s Virgin Galactic has a back-listed manifest of dozens of people desiring a suborbital thrill ride (at a cost of a few hundred thousand dollars), those journeys are infinitely more affordable than a possible orbital trek (which will cost several tens of millions of dollars, at least initially).  Nevertheless, there will no doubt be takers for a ticket.  But what will happen to a commercial space tourism market after the first fatal accident?  New Space advocates often tout their indifference to danger, but such bravado is neither a common nor wise attitude in today’s lawsuit-happy society (not to mention, the inevitable loss of confidence from a limited customer base).  My opinion is that after the first major accident with loss of life, a nascent space tourism industry will become immersed in an avalanche of litigation and will probably fully or partly collapse under the ensuing financial burden.  We are no longer the barnstorming America of the 1920’s and spaceflight is much more difficult than aviation.

Despite labeling themselves “free marketers,” New Space (in its current configuration) looks no different than any other contractor furiously lobbying for government sponsorship through continuation of its subsidies.  True free-market capitalists do not seek government funding to develop a product.  Rather, they devise an answer to an unmet need, identify a market, seek investors and invest their own capital, provide a product or service and only remain viable by making a profit through the sale of their goods and services.

Tumlinson bemoans the attitude of some politicians, ascribing venal and petty motives as to why they do not fully embrace the administration’s new direction, e.g., the oft-thrown label “space pork” to describe support for NASA’s Space Launch System.  In regard to New Space companies, Tumlinson asserts that, “[We] have to both give them a chance and get out of the way.”  But in fact, he does not want government to “get out of the way” – at least not while they’re still shoveling millions into New Space company coffers – nor when they need (and they will) a ruling on, or protection of, their property rights in space.  Any entity that accepts government money is making a “deal with the devil,” whereby it is understood that such money comes with oversight requirements (as well it should, consisting of taxpayer dollars).

Questions about the vision boil down to whether we want to incorporate the Solar System in our economic sphere, or not.” – Presidential Science Advisor John Marburger, 2006

Successful commercialization of space has occurred in the past (e.g., COMSAT) and will occur in the future.  But the creation of a select, subsidized, quasi-governmental industry is not by any stretch of the imagination what we commonly understand free market capitalism to mean.  It is more akin to oligarchical corporatism, a common feature of the post-Soviet, Russian economy.  True private sector space will be created and welcomed, but not through this mechanism, whose most worrisome accomplishment to date has been to effectively distract Americans from noticing the dismantling of their civil space program and preeminence in space.

Swirls in Mare Ingenii, far side of the Moon

The Moon, unlike Earth, has no global magnetic field but many surface locales of limited extent (tens of kilometers across) are magnetized.  In many instances, these small areas of high magnetic intensity are associated with unusual patterns of surface brightness (albedo, or degree of reflectance) that occur in curved, blotchy or other strange “swirl-like” shapes.  First observed by telescope, lunar scientists have been puzzled by the possible origin of what they imaginatively named “swirls.”

An example of a lunar swirl is a feature named Reiner γ (pronounced “Reiner gamma”), a bright splotch in southern Oceanus Procellarum, the dark mare region of the western near side.  The name indicates that initially this feature was thought to be an isolated peak of highland material that juts up through the mare (lowercase Greek letters were assigned to such prominences in the old nomenclature.)  However, even at very low sun elevations, close examination shows that this bright patch does not cast a shadow.  It is simply a bright patch on the surface, one with diffuse and nebulous edges, yet clearly more reflective than the surrounding dark mare material.  It does not appear to be associated with any crater or other surface feature.  It’s as though someone smudged a finished painting of the lunar surface.

During later Apollo missions, orbiting vehicles released “subsatellites” (small spacecraft that continued to orbit the Moon long after the crews had left for home) carrying instruments to measure the Moon’s magnetic field.  Interestingly, they found a very strong magnetic field enhancement around the Reiner γ feature.  Moreover, numerous other swirls were found elsewhere on the Moon, especially on the floor of the huge South Pole-Aitken (SPA) basin in Mare Ingenii on the far side, and on the eastern limb of the Moon near Mare Marginis.  Each newly seen swirl was found to be associated with a magnetic anomaly.  However, the converse statement is not true – not all magnetic anomalies have associated swirls.

Two principal models emerged to explain these relations.  One model held that the swirls and the magnetism were contemporaneous – the swirls were surficial deposits caused by the scouring of the surface during the impact of a comet.  In this model, the cometary coma (i.e., the dense gaseous “atmosphere” surrounding the icy nucleus) struck the Moon at high velocity, scouring the surface and increasing its brightness while at the same time embedding the soil with a strong magnetic field caused by the creation of an impact-generated plasma (high temperature, low density matter).

The other model suggested that the magnetic anomalies pre-dated and were the cause of the swirls.  The lunar surface darkens and becomes redder with time owing to exposure to the solar wind (the stream of energetic particles – mostly protons – from the Sun).  Strong, localized magnetic fields serve as protective “bubbles” that caused the incident solar wind to flow around these tiny areas, darkening the edges of the field bubbles with enhanced flow but preserving the inner zones (which were shielded from the solar wind) as bright patches.  Thus, the bright parts of the swirls are areas that have not undergone “weathering” by the solar wind while the dark parts are zones that have experienced excessive space weathering.

Magnetic bubble created in the laboratory (RAL/Univ. York)

It remained uncertain whether this postulated “magnetic bubble” effect would actually work but recent experiments suggest that these bubbles might well operate on the Moon.  Scientists from the UK’s Rutherford Appleton Laboratory, creating a “solar wind tunnel” to observe the interactions of streaming plasma and confined magnetic bubbles, successfully produced a magnetic bubble under simulated space conditions.  They have compared the flow field around the laboratory magnetic bubble with the observations from orbiting spacecraft of lunar surface magnetism and find that the solar wind would be diverted around these magnetic anomalies on the Moon.  If solar wind darkening is the primary process that darkens the surface, we may have an explanation for the creation of the bright swirls.

The astute reader will note that while this bubble model might account for the origin of the swirls, it begs the question about what caused the magnetic field anomalies in the first place.  That remains a mystery.  It was noted many years ago by my colleague Lon Hood of the University of Arizona that many of the magnetic anomalies on the Moon are at the antipodes (i.e., 180° away from the center) of some of the youngest, large impact basins on the Moon.  The largest concentration of both surface magnetic anomalies and swirls are on the floor of the large SPA basin, near Mare Ingenii on the lunar far side.  This area is directly antipodal to the large, young Imbrium basin on the near side.  Likewise, the Mare Marginis swirls and magnetic fields are antipodal to the Orientale basin on the western limb (the last of the large lunar multi-ring impact basins).  Furthermore, as basins tend to cover the entire Moon, one can find a basin near the antipode of almost any given feature (note well: the swirl that started all this hubbub, Reiner γ, isn’t antipodal to anything in particular).  But an even more significant issue is that while the basin antipodal association of many swirls is intriguing, it does not explain why we should see a zone of enhanced magnetization at such locations.  Igneous intrusion, concentration of impact-generated plasmas and converging ballistic ejecta have all been proposed but no specific mechanism seems to emerge as the magnetic field creating event.

We are left with a continuing and highly unsatisfactory situation – a possible explanation for the development of surface swirls on the Moon and of their association with magnetic field bubbles, but we still don’t understand the origins of these fields, the cause of their shapes and intensities and how they fit into the continually vexing problem of lunar magnetism in general.  Two steps forward and one step back.   Lunar science marches on.

Two Presidential announcements on space

In the aftermath of a major Space Shuttle accident, an incumbent President decides that our civil space program needs a bold new strategic direction.  In a major public speech, he outlines a path to return to the Moon and go to Mars.  The space agency responds with full-color sales brochures, committee meetings, community workshops, and a thousand charts outlining the steps they will take to carry out the new direction.  A couple of years pass, a new President takes office, and then – promptly cancels the initiative of the previous administration.

Sound familiar?  This has happened in our space history – twice.

In 1989, after much agency soul-searching following the loss of seven crew members aboard the Space Shuttle Challenger, President George H. W. Bush took to the steps of the National Air and Space Museum and announced what was soon dubbed the “Space Exploration Initiative (SEI),” a long-range program to send people beyond low Earth orbit, first to the Moon and then to Mars.  NASA responded to this challenge by outlining an architecture imaginatively named the “90-Day Study.”  It called for the development of new launch vehicles, new modules, transfer spacecraft and numerous robotic elements, including lunar and martian orbiters and landers (most of them extensions of existing hardware and designs).  Financial analysts somehow arrived at an aggregate cost of $600 billion (which also included assembly of ISS) and everyone gasped.

After numerous politicians and bureaucrats scoffed disapproval, a special ad hoc group was convened to re-examine the objectives and devise a less expensive approach for implementing SEI.  Their report was delivered and immediately put on the shelf.  In the ensuing three years, a new NASA Administrator was named, Congress refused to increase the NASA budget, and President Clinton cancelled SEI.

In 2003, the Space Shuttle Columbia disintegrated during re-entry, killing its crew of seven.  The agency investigated and concluded that foam shed during launch destroyed the integrity of the vehicle’s thermal protection system, causing the loss of the Shuttle.  In January of the following year, President George W. Bush announced a new strategic direction for space – the “Vision for Space Exploration (VSE),” a long-range program to send people beyond low Earth orbit – first to the Moon and then to Mars.  NASA responded to this challenge by outlining an architecture to implement the new direction that called for the development of new launch vehicles, new modules, transfer spacecraft, and numerous robotic elements (including orbiters and landers for both the Moon and Mars – most of them extensions of existing hardware and designs).

Once again a committee was convened to examine the agency’s implementation of the new direction.  Another report was written and put on a shelf.  During numerous meetings and workshops spread over several years, an architecture emerged – accompanied by many charts (all electronic this time – technology marches on!). President Obama terminated the VSE in April, 2010 during a speech at the John F. Kennedy Space Center (“We choose NOT to go to the Moon!” – the historical resonances astound!).

What, if anything, is to be learned from these two sequences of events?  According to Mark Albrecht, Executive Secretary of the National Space Council in the Bush-41 White House, it means that the space agency is fundamentally broken – comprised of various constituencies that protect turf and resist implementing any new direction that may challenge or threaten their existence.  However, there is another possible reading of the situation.  The space agency was in a very different predicament during SEI than it was during the VSE.  In 1990, NASA had a clear but unfulfilled mission – Space Station Freedom, for which not a single element had yet been launched.  NASA’s anxiety at the time was uncertainty in being able to execute both Station and SEI simultaneously.  The oft-quoted 30-year, $600 billion cost of SEI, repeated by the media to denigrate the effort, included construction and operation of Station, which was to serve as both an orbital platform for missions beyond LEO and as a source of hardware (e.g., habitation modules) that could be adapted to trans-LEO missions.  Even so, most of the costing assumptions in the 90-Day Study were inflated beyond reason, presumably following in the footsteps of former NASA Administrator James Webb, who after reportedly being told that Apollo would cost about $20 billion, asked for more than $35 billion as a cushion.

In contrast, the VSE came along just as NASA was in the middle of ISS construction, with the program’s end clearly in sight.  There was no future plan for human spaceflight beyond Shuttle/ISS and the agency sorely needed some high-level direction.  The idea of Shuttle replacement came from the Columbia Accident Investigations Board report, which contended that the Shuttle system was inherently dangerous and that we ought to develop a new space transportation system as soon as possible.  In contrast to uninformed reporting and Internet mythology, President Bush did not “retire” the Shuttle – he ordered that it first be brought back to flight status (so that ISS construction could be completed) and then transitioned and replaced with new human spacecraft capable of journeys beyond LEO (which became the now-cancelled Project Constellation).  In contrast to SEI, the VSE came to NASA with price limits already in place – after a small incremental increase in the early years, it was to cost no more than we were then spending on human spaceflight (about $8 billion per year) with funding available from the gradual decline in spending on the Shuttle/Station program.  Finally, unlike SEI, which never had much Congressional support, NASA was given two Authorization bills (in 2005 and 2008) that strongly endorsed the VSE (many VSE goals, though ignored, remain in the current 2010 Authorization).

Although neither SEI nor the VSE succeeded in their principal objectives of sending people beyond low Earth orbit, they did manage to greatly advance our understanding of just what is at stake.  In the case of the former, a variety of people from the defense and civil space sectors worked together on SEI, creating networks that advanced an outbound agenda.  One accomplishment was the Clementine mission, a joint effort by the Department of Defense’s Strategic Defense Initiative Organization and NASA.  Flying in 1994, Clementine successfully mapped the entire Moon in eleven spectral bands, mapping its mineral composition in detail.  Clementine made the first global topographic map of that body and most significantly, found evidence for the presence of water ice in the dark areas near the south pole of the Moon.  The success of Clementine led to the Lunar Prospector mission, a robotic orbiter flown under NASA’s Discovery program, that both confirmed the excess hydrogen at the poles of the Moon and globally mapped the Moon’s chemical composition.

The intriguing results from Clementine and Lunar Prospector resulted in an international fleet of six spacecraft being sent to the Moon in the past decade, adding to our knowledge of the processes, history and potential utility of that body.  From this exploration, we now know that the Moon contains millions of tons of harvestable water.  We possess detailed maps of lunar physical and compositional properties.  In short, we now know that the Moon is habitable and is both an appropriate near-term destination for people and a unique enabling asset for future spaceflight within and beyond the Earth-Moon system.

Now, just as we find the Moon to be an attractive destination, we shrink away from the challenge, watching as others blaze trails we once traveled.  We willingly accept the pablum to not fret over new space powers who do not cancel their programs.  We are told they have not yet done all that we have and that we still carry the mantle of the world’s leading space power.  This is not logical. Similar thoughts once prevailed in Portugal, during an earlier age of exploration.  One doesn’t assume or retain the mantle of leadership by fiat or declaration – it must be earned and exercised.  Perhaps the real issue is not whether NASA is up to the task but rather, whether we as Americans are blind to the truth, unable to recognize that by having our nation withdraw from this arena, that we are retreating from our position, thereby ceding our prosperity, leadership and greatness to other nations who do have the will and the vision to press forward.

Shenzhou 9 lifts off for rendezvous and docking in space

With the weekend launch of the latest Shenzhou spacecraft and its successful rendezvous and docking with an orbiting space station, world attention is once again focused on China’s flourishing space program.  Although China’s human spaceflight efforts currently focus on low Earth orbit, in recent years they have sent two robotic orbital spacecraft to the Moon and have announced their intentions for a lunar lander/rover mission.  These efforts lead many in the west to speculate that a presence on the Moon is a likely and realistic goal for China’s space future.  In terms of the possible purpose for such lunar efforts, things are little more vague.  Most assume that China will go to the Moon for reasons similar to the geopolitical motives that impelled America to undertake the Apollo missions.  While some actually welcome China’s aspirations to conquer the Moon, other space observers smirk at their apparent willingness to (as they characterize it) “waste billions of dollars to repeat what America did thirty years ago.”  Others understand why China aims for the Moon.

The United States currently has no strategic space goal.  Many in the U.S. space community argue that the development of commercial launch services through federal subsidies is a goal.  To smooth the path for this approach, calls for consensus have been made by some New Space advocates.  Funding to support the research and development costs of these new commercial services would come by excising chunks of the rapidly dwindling NASA budget.   “Flat or declining” now describes the American civil space program budget and regularly reaching LEO to supply ISS has become our “new” vision.

In contrast, China is conducting an incremental, step-wise effort to gradually but inexorably extend their reach and influence in space, first into low Earth orbit and then into cislunar space and beyond.  Their approach uses a variety of hardware derived from existing systems while adding new capabilities over time.  China appears to be focused and following clear, long-range goals in space.  Because we do not look ahead on timescales of 20-30 years (accustomed instead to a 5-10 year timeframe), we have no long-range strategy to guide what we build or a plan for securing any long-term space goals.

Certainly wide-ranging concerns propel China’s push for human space access, some that can be envisioned now and some that cannot.  But fundamentally, they have accepted the proposition that freedom of space in the 21^st century is equivalent to the principle of freedom of the seas that governed 19^th and 20^th century geopolitics.   In short, such a principle comprises the ability to project power and to protect national interests whenever and wherever China might be confronted within the strategic theater in question, in this case, the domain of cislunar space.

I have written before on the economic, strategic and scientific value of cislunar space, the zone in which virtually all of our space assets and satellites reside.  China intends to preserve her freedom of action by creating a spaceflight capability that can access and use any location of cislunar space, up to and including the lunar surface.  To build a sustainable space program using incremental, cumulative steps, it makes no sense to “leapfrog” over (or to ignore) the intermediate locations from which space faring capability and utility can be demonstrated, established and used.

Much of the published speculation on China’s interest in the Moon focuses on mining the Moon for the nuclear fusion fuel ³He or substances found on the lunar surface, such as titanium or rare earth elements.  In fact, one of the simplest substances found on the Moon has enormous value in space – water.  Water can be used to support human life, as a medium of energy storage, and as rocket propellant.  Water is the currency of spaceflight and one of the most valuable, usable substances we could obtain from any extraterrestrial object.

If I wanted to establish a secure foothold for my country in cislunar space, I would secure the territory near the poles of the Moon.  We know from the results of several recent probes that the lunar poles contain billions of tons of water, much of it chemically unbound as ice, a particularly easy form to harvest, concentrate and use. Material and energy resources, concentrated together in a compact location are assets of immense economic and strategic value.  Wars have been waged over less.

International treaty prohibits claims of extraterrestrial territory by national entities.  But treaties are “gentlemen’s agreements” and sometimes nations do not behave like gentlemen.  There is no mechanism to enforce the 1967 Outer Space Treaty except for a given country’s unwillingness to undergo international opprobrium.  Moreover, a country can withdraw from the treaty at will.  China tends to do what it wants to do, unless the economic or political price is perceived to be too high.  The potential of the Moon and cislunar space may outweigh their sense of geopolitical risk or concern about international ostracism.

What does this mean for the United States?  To listen to many in the space press, nothing.  A quick yawn and then back to propagandizing for more federal dollars to be passed on to new space companies.  But ultimately, it could mean that their libertarian dreams of a profit-making space frontier will never come to pass.  If free market capitalism and democratic political institutions are to have a future in the new frontier of space, entities, investors and consumers who share these values must secure a notable presence.  If the United States has a vigorous civil space program that creates a permanent presence there, such a system may have a chance to take root.  Conversely, our absence is almost a guarantee that our system and values will not be the guiding paradigm on the new frontier.

For many observers, an absent America (or with a mere supporting role) would be acceptable.  They believe America is what’s wrong with the world and that it’s high time that we step aside (in their opinion to one of subservience and irrelevance – certainly not one of power projection or as an economic engine and technology driver).  Parties (and countries) that lead make the rules.  While China has a great industrial base and a large, seemingly market-based economic system, it is actually a system of big government corporatism, where central planners decide which industries shall be allowed to grow and in what direction – capitalism, under total governmental control.

China is a rapidly advancing technically and is one of our largest trading partners, attributes beneficial in relationships between equals.  Historically, once a shift occurs in the status of partners, relationships change.  Because China’s influence in the world is growing, it is vital that we discuss and weigh these facts.  Our national economic and security interests cannot be jeopardized by a misguided rush to hand our space future over to companies who are in the imagining stage of what China just accomplished this weekend.

A lunar base creates new capabilities (Pat Rawlings/SAIC)

Where does the Moon fit into plans for future human space exploration?  From reading the space media, you might get the idea that the very notion is dead and buried, killed by President Obama’s casual dismissal of the idea in a speech over two years ago at NASA’s Kennedy Space Center, followed this year by Mitt Romney’s dismissive remarks on the Moon during the Republican primaries.  Nevertheless, many in the international community (and in the United States) are keeping the lunar flame alive for a variety of reasons, not the least among them being that it is understood that politicians aren’t rocket scientists – nor should we expect them to be.

The Global Exploration Conference (GLEX) held last month in Washington DC was remarkable for the fact that most of our international space partners are proceeding with plans for lunar return as though its abandonment had never occurred.  The Russians were particularly eager to express their desire to establish capability on the Moon at the meeting, while in recent months strong interest in permanent lunar return has been expressed by the Europeans, Canada, India, Japan and of course, China.  Moreover, unlike many within our own national space agency, the world sees the Moon not simply as a box to be checked-off on the way to Mars but as the enabling asset for space exploration.  As Vladimir Popovkin, head of the Russian Federal Space Agency Roscosmos put it, “It’s a new Moon,” pointing out that the recently confirmed discovery of water at the poles of the Moon enables sustainable, permanent habitation of that body and the creation of new capabilities for voyages to the planets.

Our international space partners believe that spaceflight beyond LEO should entail incremental steps that will gradually extend reach and capability.  Once such a paradigm is adopted, expensive designer missions to plant a flag or do a “touch-and-go” at an asteroid are seen as having limited value and making no economic sense.  On the other hand, the gradual expansion beyond LEO using nearby assets builds a permanent, lasting space faring capability.  The Moon fits into such a scheme by virtue of both its proximity and usefulness.  In the absence of some technical miracle, such as the discovery of new physics that fundamentally change the nature of spaceflight, we are wedded to rocket technology for the foreseeable future.  The rocket equation dictates that it will remain difficult and expensive to reach space and operate there.  Given such problems, some now recognize and conclude that the Moon offers provisioning capability and for this reason and many others, is a desirable destination and near-term goal.

Our pioneering (and current) model of space access requires launching everything from Earth’s surface, taking months to complete a mission, yet gathering minimal information (due to limited time in the vicinity of its designated target) and leaving no lasting or reusable infrastructure in space.  This template guarantees that human spaceflights will be infrequent, expensive and subject to abrupt cancellation due to political whims.   If one views the civil space program primarily as an annoying expenditure whose ambitions must be constrained by making a previously small portion of the program (such as “commercial” launch services) the raison d’être of the entire effort and deferring any real goals to an indefinite and nebulous future, our current path might seem completely reasonable.  However, it appears that the international community believes that space is a real theater of human endeavor and their goal is to make it part of their domain and utility – until recently, also a goal of the American space program.  Perhaps it still is.

Despite common perception, the Moon has not been officially abandoned as a goal for the United States space program.  The current NASA Authorization Act of 2010 lays out the goals and approaches to be followed by the agency in executing its mission.  The Findings by the Congress (section 301) outlines the rationale and goals of the space agency’s human exploration efforts.  As I have written previously, in the seven points dealing with future agency activities, cislunar space is mentioned in four and the lunar surface is called out twice as destinations.  Development of the ability to use the in situ resources of space to create infrastructure is specifically cited in Sec. 301a (4).  The entire section 301 is worth a careful reading.  It calls for a program that uses a gradual, incremental approach to the extension of human reach in space beyond LEO, specifically specifying both commercial and international participation.  There is nothing in the current law that is at odds with the plans and desires of the international community as expressed at the recent GLEX meeting.  The only place one reads about the Moon being abandoned as a national goal for America is in the press and such cases, it is always in the context of a single off-hand remark in one Presidential speech.

From the perspective of two years later, that off-hand remark sounds increasingly ill thought-out and hollow.  Given its context in the speech, the statement seems to derive from the idea that lunar return must perforce be a repeat of the Apollo experience of 30 years ago.  NASA itself has fed this idea, depicting the return to the Moon as the equivalent of a Gemini program within the Apollo-to-Mars fixation of many in the agency.  In their 2006 preliminary plans for lunar return, NASA started out properly by describing the development of an outpost at one of the poles of the Moon and emphasizing human presence and development, but over the next few years architectural studies increasingly drifted away from an outpost and towards the sortie concept, in which we would stage (entirely from Earth) and execute one-off missions to sites of scientific interest all over the Moon for visits of limited duration.  Such an exploration approach dissipates assets and thus increases costs and reduces surface capability and infrastructure.  It was this exploratory approach to lunar return that the Augustine committee evaluated and declared to be “unaffordable,” not the concept of building a centralized outpost that could support ISRU and space development (an approach that the committee did not even consider).

President Obama signed the NASA Authorization bill of 2010 – a bill crafted when his party controlled Congress – and the findings presented in that bill are now law.  So even though the agency and most of the media seem to be blissfully unaware of it, NASA has been charged by Congress to develop space systems capable of conducting missions to and throughout cislunar space, including to the lunar surface.  Our international partners agree with this intended direction, convinced that the Moon is the appropriate next destination for humans in space.

NASA’s reluctance to go in this direction, even while other nations are making plans, forfeits the opportunity for our international leadership in space.  Our space program has to demonstrate the feasibility of using lunar resources to secure us a place as participants and entrepreneurs in the vast economic future of space.

The Luna 24 lander descent stage on the Moon: Wishing Well? (NASA/ASU)

A recent article tells how Soviet scientists studying soil samples returned from the Moon in 1976 by the unmanned Luna 24 mission first discovered lunar water.  This assertion is based on a paper published in the Russian journal Geokhimiia (vol. 285, p. 285-288, February 1978).  The measurement used infrared absorption spectroscopy to look for the “water band” centered around 2.8 microns, the same technique used recently by several groups to map the water band on the lunar surface regionally from flyby (Cassini and EPOXI) and orbital (Chandrayaan-1) spacecraft.  The Soviet paper claimed to detect water at a level of about 0.1 weight percent.  This high concentration level of water raised my antennae.

The discovery of significant amounts of water would tell us about lunar processes and history as well as provide evidence that water might be manufactured on the Moon to support future exploration.  The first lunar samples returned to Earth in 1969 by the Apollo 11 mission were intensely scrutinized for water content.  Besides being exceedingly dry, the chemistry of the Apollo samples suggested they were created in a completely anhydrous, reducing environment.  Samples from subsequent missions confirmed and extended this initial impression to the point where talk of water on the Moon was mostly dismissed.

A rock returned in 1972 by the Apollo 16 mission displayed visible brownish splotches which turned out to be “rust” in the form of the mineral akaganeite, an iron-hydroxyl phase, with minor amounts of chlorine.  This mineral could have formed by the aqueous alteration of the iron-chlorine mineral lawrencite found in some meteorites.  However a source of water is still needed to create the “rust,” so for several years the source of the water and the nature of the alteration were debated.  Did water come from the inside of the Moon or from an impacting comet?  Did the oxidation occur on the Moon or was it caused by the exposure of the highly reduced lunar sample to humid air (from inside the returning Apollo command module or the Houston summer humidity)?  Different workers had a variety of opinions but with no resolution, interest faded.

But a few inquisitive types didn’t forget it.  Jim Arnold, a chemist from UC-San Diego, resurrected an old idea about permanent cold and dark areas near the lunar poles.  He concluded that over the course of history these areas were cold enough and old enough to have accumulated significant amounts of water from meteorites and comets.  Groups studying the regolith (soil) from the Apollo missions measured variable amounts of hydrogen on dust grains; when heated, hydrogen in that dust reacted with metal oxides in the soil producing native metal (iron) and water vapor.  Although done in the laboratory, it was shown that the process could occur naturally on the Moon during the impact of a micrometeorite, whose energy is mostly dissipated as heat.  This heat and the hydrogen on dust grains could “reduce” the soil, creating measurable water release.

During the lunar “wilderness years” (i.e., 1976-1994, when no one was going to the Moon) all we could do was speculate and analyze existing samples.  In 1982 a meteorite from the Moon was discovered in Antarctica.  Lunar meteorites provided a new source of samples but even though all had significant exposure to the terrestrial hydrosphere, none of them showed evidence for water-bearing phases.  Attempts were made to map the poles of the Moon from Earth using optical and radar telescopes but poor viewing geometry led to uncertain conclusions.

Two events re-ignited the water debate.  The 1994 Clementine spacecraft probed the south pole of the Moon and found evidence for coherent backscatter near the dark areas.  The team interpreted this as indicating the presence of water ice.  Following Clementine, the Lunar Prospector neutron detector found elevated amounts of hydrogen near both poles of the Moon, resulting in new interest about the possibilities for water on the Moon.  In recent years, a variety of robotic missions, carrying instruments designed to address the lunar water question one way or another, found large amounts of water in a variety of different forms, locations and concentrations.  We are just beginning to decipher the origins, cycles, and eventual fate of this water.

So what can we say about the Soviet results published in 1978?  No other scientist or group has repeated this measurement on the Luna 24 samples to confirm its validity.  Under a reciprocal exchange agreement with the Soviet Union in the late 1970s, others studied the Luna 24 samples but none reported any traces of water in their samples.  No one in Russia has studied the Luna 24 samples in years (at least to my knowledge), although they still exist and presumably are available for analysis.  The spectral detection of water in the Luna 24 soil should be repeated and then followed up with analyses by other techniques to confirm the water’s presence and to cross-check the amounts claimed.  The published value of 0.1 weight percent (1000 part per million) water seems very high for lunar soils from equatorial and mid-latitudes; typically, such soil contains 10-50 ppm hydrogen, almost two orders of magnitude less than the 1978 reported result.  Finally, even if the old analysis is confirmed, questions about its source are still pertinent; we are still arguing about the origin of the water that made the rust in “Rusty Rock.”

If you’ve stayed with me this far, I hope that if nothing else, this brief history of a lunar controversy has shown that it is difficult (I would say impossible) to assign “credit” to any one paper or worker or group for the discovery of water on the Moon.  In science we always proceed from the knowledge gained by previous work.  Sir Isaac Newton put it well when he famously said that he saw more clearly because he stood on the shoulders of giants.  A lunar scientist’s goal is to study, document and explain, thereby contributing to and advancing our knowledge and understanding of the Moon.

The near-Earth asteroid, Eros.

There’s quite a buzz in space policy circles over the recent announcement of the creation of a new company that intends to survey, study and mine near Earth asteroids (NEAs).  Given my previous advocacy regarding the desirability of learning how to extract and use off-planet resources, many people have asked me to weigh in with my opinion of their proposed business plan.  I’d like to frame my remarks around Michael Listner’s recent piece on the possible legal issues involved in the plan as he has illuminated an interesting angle on the project.

The roll-out of the business plan of Planetary Resources Inc. made a big media splash, as is typical for many of these “New Space” private operations.  Close examination reveals the outline of a plan, but the technical details are rather fuzzy.  Given that no business should reveal too much detail about their plans lest they lose their competitive advantage, the company’s reticence is not too surprising.  To summarize it in broad terms, the plan is to launch a space-based telescope, dedicated to identifying candidate NEAs; at least initially, the main interest seems to be metal asteroids (presumably those rich in metallic elements of economic value, including gold and platinum) and water-bearing asteroids.  The former would have significant economic value in terrestrial markets, providing the possibility of high, near-term payback for investors.  The latter would have value for future in-space operations and could be sold to both national governments and to the private sector, presuming that such markets develop.

The next step involves sending robotic prospectors to the best candidate bodies to survey them, determine their physical, chemical and mineralogical make up, and identify the best targets for resource extraction.  The last step involves snagging a small asteroid (possibly several tons in total mass) and tow it back to cislunar space where Earth-based, teleoperated robotic machines can process and refine the material for sale.  This last step contains the most open questions.  Although such a mission can be envisioned in principle, it is technically out of reach at the present time.  However, I envision no particular show stoppers here – practical details of the material processing and handling these materials in microgravity are the biggest unknowns, but even these issues can be addressed and mitigated before any NEA is retrieved through the execution of some carefully designed experiments in low Earth orbit.

But then what?  This – as always is the case when human endeavors begin in earnest – is where the lawyers come in.

Listner’s article suggests that the proposed activity of capturing and processing an asteroid falls outside the current bounds of any outer space legal regime.  He recalls that the terms of the 1967 Outer Space Treaty (to which the United States is a signatory) prohibits claims of national sovereignty over extraterrestrial objects.  Space mining companies will be subject to the laws of the nation in which they are incorporated and thus, bound to the terms of any international treaty that nation has ratified.  While national ownership of outer space assets is prohibited by the 1967 treaty, the treaty is silent on private ownership.  Thus, the treaty is open to interpretation and subject to the philosophical and economic predilections of the parties involved.  One thing is certain however – if anyone ever does this, they are guaranteed to face protracted litigation that will no doubt take years (and many billable hours) to wind its way through the courts.

Listner goes on to describe issues with liability, mostly in relation to possible damages caused by future space operations or to existing space-based assets.  However, other more alarming scenarios are possible (e.g., suppose a retrieved NEA collides with the Earth during its arrival in cislunar space?)  Although no specific conclusions are drawn, the foreshadowing is a prerequisite for private companies to post a surety bond, one potentially of enormous scale.  If nothing else, such a requirement would certainly put a crimp in many new commercialization plans.

The infamous (at least in space circles) Moon Treaty is the last legal issue discussed by Listner.  In brief, this treaty prohibits private ownership of space bodies and demands that any profits from resource extraction from these bodies be “distributed” amongst the nations of the world.  This document was submitted to the United States Senate in 1980 for ratification and was defeated, thanks to a vigorous educational campaign by the L-5 Society.  Thus, thirty-two years ago, the United States (and also other major space faring nations, including Russia and China) rejected the Moon Treaty.  However, from the standpoint of most lawyers, the treaty has been ratified by 17 nations, giving it the full force of international law.  Considering the multinational make-up of many companies and that their corporate assets can be frozen or in some extreme cases seized (sometimes for entirely specious or arbitrary reasons), the legal status of the use and ownership of extracted space resources must be considered seriously.

Where does this legal confusion leave the prospects for the economic development of the Solar System?  That is unclear at the moment.  In broad terms, business does not like legal uncertainty to a degree usually in direct proportion to the amount of money involved.  For both technical and legal reasons, it is highly unlikely that there will be a “gold rush in space.” The technical issues are substantial (particularly for the Planetary Resources Inc. plan) but the legal ones are no less so.  In part, this is why I favor making the determination of how to extract and use off-planet resources a central goal of the American civil space program.  Note well: I do not say that we should turn NASA into a space mining company.  Rather, the role of government is to undertake technically risky ventures with the aim of determining how difficult they might be and to settle any thorny legal issues that may arise.  Questions of international law can only be addressed and settled by national governments – through agreements, treaties, new law and if need be, by stronger actions.  No private sector corporation has this inherent ability – only national governments can resolve these issues.  If such issues are resolved, the private sector can then successfully proceed and grow their businesses and governments will profit too.

I applaud both the vision and the chutzpah of Planetary Resources Inc.  For now, their plan to launch and operate a space-based telescope to map asteroids and locate promising prospects is a good start.  They may even manage to eventually send a probe of two for a close-up examination of a couple of NEAs.  As for the last piece of their plan, at this writing, color me skeptical.

* Henry VI Part 2, Act 4, Scene 2.  Yes, I am aware that lawyers claim that this phrase is taken out of context (i.e., it is actually an ironic assertion that if one wants a poorly run, bad society, eliminate the rule of law), but it is simply too good not to use here.

From the oceans, from the stars. Arthur C. Clarke

Space flight has very little in common with aviation; it is much closer in spirit to ocean voyaging – Arthur C. Clarke, Profiles of the Future: An Inquiry into the Limits of the Possible, Harper and Row, New York, 1963.

The current drift of America’s civil space program has many reaching to discuss the philosophy and methods we rely on to pursue space travel.  Of late, the quote above (which I first read in high school in the late Sixties during my Arthur C. Clarke omnivorous reading campaign) has been tapping me on the shoulder.  Clarke’s captivating style gripped me for some time as I worked my way through both his fiction and non-fiction oeuvre.  Curiously, the above thought has stayed with me, and although I’d forgotten exactly where and in which of his books it occurred, I knew it was his and was able to find it.

From the beginning of the Space Age in 1957, spaceflight and rocket development has had a strong association with aviation, particularly the military variety.  The first astronauts were all military aviators (regardless of their branch of service) and those origins solidified the association of aviation with space.  Air Force public relations devised the term “aerospace” to make the association explicit.  The Army and the Navy had their own missile programs but the bulk of the early research and development was done to facilitate the deployment of a land-based ICBM system under the control of the Air Force.  Early ICBMs like Atlas and Titan (developed to lob nuclear warheads) became launch vehicles for the first human missions into space.

The analogy of manned spaceflight to aviation (at least in the first fifty years of spaceflight) is not altogether inappropriate.  Military and commercial aviation involves small crews that leave from a home base, travel great distances, sometimes fly over unknown territory (where they seldom land) before returning within a few to tens of hours.  Flight durations are short and the ability to deliver crew and cargo is limited.  In the military, this operational template is defined as a “mission,” where principal tasks are completed and then preparation for the next mission begins.  The only “permanence” in aviation is the mission.

The template for aviation has some resonating parallels in manned spaceflight. The pilot’s objective is to complete the assigned mission and return to base.  Astronauts can travel great distances, but are able to land at distant destinations only under extraordinary circumstances.  Mission duration (e.g., to the Moon) is short, on the order of a few days.  Single-purpose, one-shot trips are common and have little capability to deliver a large number of crew and large amounts of cargo.  Although the current plan is to carry more people on longer trips beyond low Earth orbit, the focus (mission) remains fixed on completing the task and returning home – not on creating a permanent, beneficial presence.

A navy has a different operational style.  Sea voyages can last many weeks or months, even years.  Navies can travel to any distant land, anchor off shore and explore it at length.  Ships are typically able to deliver large amounts of cargo and carry large crews and supplies; ships can remain for as long as is necessary to complete their assigned tasks, which can include extensive reconnaissance, including stops of varying lengths to many different ports of call.  A navy must be re-supplied on occasion and requires logistics bases (coaling stations, in 19^th century terms) for replenishment and refurbishing.  A navy both projects power and creates presence; it is the international face of the nation from which it originates.

In contrast to its parallels with aviation, space has yet to show much correspondence with seafaring.  But we should begin to think in such terms – to move away from our emphasis on one-off missions and toward sighting distant lands and conducting remote reconnaissance aimed toward the creation of a long-term presence.  The International Space Station, now continuously occupied for over a decade, is a first step and transition toward this new template.  Note that such occupation does not necessarily imply settlement or even that the same people have been there for a decade.  But we are moving gradually toward that concept as human presence extends to longer periods of time.  As we move outward from LEO, we will build beachheads – staging nodes and depots (logistics bases).  Here, spacecraft can refuel and provision themselves for journeys onward to more distant destinations.

Clarke was articulating the natural progression of human reach and operations.  To transit and settle a frontier, we initially survey and scout on custom-designed trips to obtain knowledge for future exploitation.  As we transition from this “Mountain Man”-stage of pioneering (occasional random visit to scattered points in the wilderness) to permanent bases (outposts) and then settlement (built around trading posts), we need an operational template that satisfies the new needs of space pioneers.  In order to attain and exploit the vast utility of space, longer presence of larger crews and more complex logistical arrangements (the attributes that a space navy provides) is required.

None of this is to say that a space air force is obsolete; forward reconnaissance on the edge of the frontier will always be required.  But as that frontier pushes ever outward, to distances that demand more significant logistical requirements, the naval analogy becomes more pertinent.  After all, John F. Kennedy (a former naval officer) did call space “this new ocean.”

Perceptive guy, that Arthur C. Clarke.

Uncollimated (left) and collimated (right) views of the Moon from the LEND instrument: What's being detected? (from Eke et al., 2012, LPSC 43, 2211)

Attendees at the recently concluded 43^rd annual Lunar and Planetary Science Conference had front row seats to a heated debate on new data from the Moon.  As opposed to how many envision scientific debate – coolly logical, white-frocked intellectuals, dispassionately discussing points of contention in a laboratory – what they witnessed was an impassioned and stormy exchange of differing opinions.  There is good reason for passion.  Subsequent decisions based on these data places the success or failure of future missions in the crosshairs.

Point in question: a team of scientists on NASA’s Lunar Reconnaissance Orbiter (LRO) mission claim that their new neutron mapping shows that locations of high hydrogen content are not well correlated with dark areas near the poles of the Moon.  This relation seems to contradict (at least, it is not consistent with) one of the key concepts about water at the poles of the Moon – that it occurs in dark polar cold traps, where water is stable on the surface and cannot be ejected from the Moon (as appears to be the case for most water deposited there).

This new idea is current because LRO carries something called a collimated neutron spectrometer, named the Lunar Exploration Neutron Detector (LEND), an instrument provided to NASA by IKI, the Space Research Institute of the Russian Academy of Science.  NASA flew a neutron spectrometer to the Moon over 10 years ago on a global mapping mission called Lunar Prospector (LP).  That instrument had an omni-directional (4-pi) field-of-view (FOV), meaning that it simultaneously looked in all directions.  As such, the resolution of features on the surface made by this instrument was fairly low, being effectively equal to the altitude of the spacecraft.  The LP neutron mapping spectrometer obtained a best resolution of about 30 km, meaning that any smaller feature could not be resolved in the FOV of the detector.  Unfortunately, most of the dark, cold areas near the poles are smaller than this.  LP detected enhanced levels of hydrogen in both polar regions, but couldn’t detect whether these hydrogen reservoirs were confined to the permanently shadowed areas, thus increasing the likelihood that the hydrogen was in the form of water.

In order to identify zones of high hydrogen content and determine if they were truly associated with the cold, dark areas, as predicted by theory, scientists wanted higher resolution maps of the poles for the next mission to the Moon.  The way to obtain higher resolution is to restrict the field of view of the neutron instrument to where it looks only at a small spot directly below the orbiter.  This involves putting a shield on the detector (called a collimator) that restricts the FOV to the lunar surface only; this technique can resolve areas on the surface smaller than the orbital altitude during mapping.  A drawback to using a collimator is that restricting the FOV means that the flux, or total number of neutrons that can be detected per unit time, is much lower, which greatly reduces precision of the measurements.  However, the longer the counting is conducted, the more precise the data.  LRO was to remain in lunar orbit for at least a two-year mission; it has now been orbiting the Moon and collecting data for almost three years.

Over the last year, the LEND team’s reports have appeared in the scientific literature.  To the surprise of most lunar scientists, their team claimed that in all but two or three isolated cases, hydrogen detected by LEND does not correlate with the polar dark areas.  This puzzling result would seem to indicate that perhaps we do not fully understand the nature of the polar hydrogen and the processes involved in their creation and retention.

Thus the debate commenced at last Monday’s scientific session, when several scientists (I will collectively call them the “skeptics”) who work with neutron data from LP and other missions, differed with the LEND team conclusions, who in turn vigorously defended their results as valid, citing as evidence the coincidence of laser altimetry and neutron data over one crater (Shoemaker) near the south pole of the Moon.  Having studied the LEND data set themselves, the skeptics contended that the actual average count rate for neutrons is less than half of that quoted by the LEND team, meaning that the hydrogen content inferred from the LEND data are significantly less precise than claimed.  Moreover, they estimate that the signal from the collimated (high resolution) detectors is only a few percent of the total signal, whereas the LEND team claims that it is roughly one-third of the total.  The skeptics make the point that if the collimator is working as the LEND team claim, the map derived from the collimated detector should be a sharper, higher resolution version of the low-resolution map made in the uncollimated mode.  In fact, the skeptics contend that the two maps look completely different (see figure at top of this post), suggesting that the collimated product is detecting something else; based on the observed pattern, it is probably related to the amount of iron in the lunar surface.

This is not some arcane, academic dispute.  We will depend on the mapping results from LRO to identify potential landing sites for future missions, including the selection of the most hydrogen-rich areas for exploration and possible future utilization.  Such decisions could involve the expenditure of hundreds of millions of dollars, so there is some pressure to make the correct ones.

So where does this impasse leave the lunar science community?  Mostly befuddled.  The vast majority of scientists simply do not have the time to read every scientific paper published, especially in fields peripheral to their own interests.  However, in the course of their research, scientists often find that they must decide what to believe about uncertain or controversial ideas that may relate to their own studies.  Is there a correct way to decide which interpretation to believe?  After a quick and cursory review of the competing concepts, most scientists will adopt the majority, or “consensus” viewpoint.  If they know someone with relevant expertise, they may ask for and rely on the considered judgment of that expert.  Few scientists are able to read and make their own considered judgments about a field in which they have little understanding or no expertise.  Thus, they tend to choose their position on the basis of non-scientific evaluations of the technical credibility of those arguing for or against a given viewpoint.

In this case, the detailed distribution of hydrogen at the poles of the Moon remains unclear.  While both LP and LEND uncollimated (e.g., omni-directional) maps appear nearly identical, the collimated LEND polar hydrogen maps show widely varying concentrations, with little coherence over short distances.  Repeatability of measurement is important in science.  The fact that two completely different instruments on two different missions found nearly identical results suggests that the low resolution, uncollimated LP and LEND maps are currently the best reflection of reality we have.  These uncollimated data most likely will remain the polar hydrogen maps of choice by working lunar scientists.

The lunar crater Daniell, seen from the Chang'E 2 spacecraft

Controversy quickly followed astonishment with the recent release of a white paper outlining China’s intentions in space.  Sparking particular buzz from the Internet was a statement about human lunar missions being an objective for future Chinese space efforts.  That statement drew comment ranging from sophisticated to simplistic, yet in my opinion, most of the discussion to date neglects the essential point of what this means to humanity’s future in space.

The report lays out China’s plan for missions to the Moon of increasing complexity and capability.   The Chinese orbiters Chang’E 1 (2007) and Chang’E 2 (2010) made global maps of the Moon’s morphology and topography.  The Chang’E spacecraft demonstrated China’s ability to navigate trans-LEO space.  After Chang’E 1’s mapping mission was complete, the spacecraft was deliberately de-orbited to impact the Moon.  However, after surveying a potential landing site for future missions, the Chang’E 2 spacecraft left lunar orbit and was sent to the Earth-Sun L2 point, a stable location 1.5 million km from the Earth.  This maneuver is quite complex and its successful completion demonstrated their capability to maneuver spacecraft throughout cislunar space.  It also lays the groundwork for more complex lunar and planetary missions in the near future.

The white paper reiterates the Chinese strategy of orbiter-lander-sample return for lunar exploration with robotic missions, of which the Chang’E series is the first step.  The paper mentions human spaceflight activities occurring only in low Earth orbit, specifically asserting their determination to conduct an “independent” space exploration program.  Closing remarks in that section of the report have been drawing the most attention: China intends to conduct “studies on a preliminary plan for a human lunar landing.”

In NASA terms, such wording would lead no one to conclude that anything remotely flight-ready was within a decade or two of occurring.  But our way is not their way.  The Chinese clearly are systematically pursuing a series of steps to incrementally increase their flight experience, technology base and operational expertise in low Earth orbit, but in a direction unmistakably toward the Moon and throughout cislunar space.

Despite some pronouncements of military doom – visions of Red Army Space Troopers descending upon us – a war in space does not appear imminent.  Over several pages, the report repeatedly proclaims China’s intention to “peaceably explore and use outer space,” especially in conjunction with an endless series of United Nations mandates, innumerable Moon treaties and international kumbayah.  Perhaps, as Queen Gertrude once observed, they doth protest too much.

Military action is not the only possible geopolitical threat on Earth or in space.  Although it is probably too early to tell, the real issue is how serious is China about expanding their sphere of operations beyond low Earth orbit to the Moon.  Currently, their human space program appears to be relatively benign, with simple Earth orbital missions, the construction of a rudimentary space station, crew EVA – all steps and capabilities that a nascent space faring nation must learn and develop.  Their proposed robotic lunar exploration plan likewise makes sense, in that they first orbit and map, then survey in detail to land, rove, explore and return samples.  For each step, a new capability is developed, building on existing ones, with all contributing toward a future strategic position.  Hmmmm – an incremental architecture with cumulative series of small but interlocking steps.  What a concept!

The reaction of space observers in the West seems bifurcated along the lines of “The sky is falling!” or “Who cares?”  For the former, some note that the Chinese space program is run by their military.  Moreover, the demonstration test of a Chinese anti-satellite weapon in 2007 did not engender the international peaceful good feelings so stridently expressed in the white paper.  Those who read potential danger in Chinese intentions in space are not being unreasonable, even if there appears to be no immediate threat.  For the latter group, nothing that China has done, is doing or ever could do in space would bother them.  ASAT testing?  Any alarm is labeled “hysteria.”  Chinese lunar landings?  So what?  We did that 40 years ago.  These people know not what they don’t know.  Holding such a position is patently naïve.

The real cause for concern is not a Chinese presence in cislunar space or on the Moon, but our absence from it.  Although much has been made of China’s purported movement toward capitalism in recent decades, they still possess an authoritarian political system, one with scant regard for the rule of contract law, copyright, private property and western notions of free market dynamics. Although some may not care whether China conquers the Moon, if they are the only ones on the Moon, they will determine what operational regime and legal template will prevail there.  Advocates of “commercial space” might do well to carefully consider such a scenario – commercial companies are incorporated under national auspices on Earth, pay taxes to terrestrial governments, and are subject to the laws of the country in which they are based.  They will not be free agents either in space or on the Moon.

I argued almost two years ago that there is a new “space race” but that it is quite different in character from the first one.  The outcome of this race will determine what kind of politico-economic paradigm will prevail on the new frontier of space.  One can imagine a situation in which a country establishes a permanent presence on the Moon and maintains control of the resources there.  Yes, the Moon is a big planet, but the valuable concentrations of water lie in small areas near the poles.  Water at the poles of the Moon allow a space faring entity to develop routine access to the entirety of cislunar space, where all of the economic, scientific and security space assets of many countries reside.  Space control in the new century does not refer to “Death Stars” bristling with space weaponry, but to situational awareness, assurance of service, and the defense and maintenance of space-based assets.  Control of cislunar space – meaning in this case the ability to routinely travel throughout its extent and to all the various orbits of cislunar satellites – does not mean to militarize or weaponize space, but rather the permanent presence of a space faring power of a particular ideology or worldview, undeterred by the absence of a competing ideology.

And if some say “So what?” to that, the more fool they.