Going Back to the Moon

I recently was interviewed by Space.com reporter and author Leonard David.  The interview is now posted at their web site.  Comment here if interested.

Posted in Lunar development, Lunar exploration, space policy, space technology, Space transportation | 11 Comments

Lunar Distractions

I have a new post up at Air & Space on recent NASA comments on the possible use of the Moon in a human mission to Mars architecture.  Comment here, if you’d like.

Posted in Lunar development, Lunar exploration, planetary exploration, space policy, space technology, Space transportation | 14 Comments

Dick Nixon’s Space Program

Presidential decisions and the post-Apollo space program

Presidential decisions and the post-Apollo space program

Richard Nixon is the President all good liberals love to hate – the Darth Vader of American politics: paranoid, suspicious, duplicitous and just plain evil. It should come as no surprise then that his legacy in regard to the American civil space program would come under critical scrutiny by those who idolize his opposite number, a charming, virtuous and courageous John Kennedy. JFK sent America to the Moon on a towering pillar of flame, capped by the sleek, white needle of the thundering Saturn V. Nixon consigned us to permanent space mediocrity, lumbering our way to orbit on the short, squat ugly Space Shuttle, a vehicle that brings to mind nothing more than the adage that a camel is a horse designed by a committee. Kennedy is remembered as the cool kid on the block, the budding rock star; Nixon is recalled as the old man on the corner, yelling at you to turn down your stereo and get off his lawn.

The new book by John Logsdon, the “Dean” of American space policy historians, is titled After Apollo? Richard Nixon and the American Space Program. It is an engrossing read, but perhaps not in the way its author intended. As I made my way through the narrative, I continually recognized a different way to interpret events. That is not necessarily a criticism of the book per se, but as Logsdon is apparently intent on drawing “policy lessons” from the history of the decision to build the Space Shuttle, we should carefully consider exactly what those lessons might be.

The familiar story of the post-Apollo space program is well known to space advocates. As it is told in some circles, the brilliant achievement of the lunar landings was squandered by the skinflint Nixon in deciding against a manned mission to Mars (the next obvious goal). To his credit, Logsdon does not advance this popular mythology; his take is more subtle. He carefully outlines how Nixon took full advantage of the international prestige and goodwill that America received from the success of Apollo 11, but notes that Nixon did not have any particular interest in or love for the space program in general (but then, neither did Kennedy). How to move forward on a constrained and limited budget was the fundamental problem the American space program faced after Apollo. That the budget would be lower than Apollo (and in fact, much lower, although the exact amount was unknown at the time policy decisions were made) was a foregone conclusion. In September of 1969, a report from the Space Task Group (chaired by Vice President Spiro Agnew) advocated that a manned Mars mission should be America’s next major space goal. But that program direction was a non-starter in the White House, a non-starter on the Hill and a non-starter with the public.

Given this level of ambivalence, what was possible for America’s civil space program in the post-Apollo era? As more had to be done with less money, many believed that lowering the cost of space access was critical. This led to the idea that a reusable space plane would assure both lower costs and routine access to orbit. Although routine flight was achieved with the Shuttle, the technology needs for low cost were not fully understood and never really possible. Mythology has it that the completely reusable, winged booster + shuttle design of Max Faget was passed over for a cludgey, partly reusable drop-tank camel design of the eventual Shuttle. In fact, the fully reusable design was a “bridge too far” and would not have worked then (and even today, its feasibility is questionable). But even the partly reusable Shuttle could not live up to the high hopes for a low cost option of the “sophisters, economists and calculators” (in Edmund Burke’s memorable phrase).

In great detail, Logsdon traces the debate within the Executive Branch, an ongoing argument between NASA, the White House Science Advisor (later OSTP, Office of Science and Technology Policy) and the Bureau of the Budget (later OMB, Office of Management and Budget). To sell the Shuttle, NASA had to recruit multiple customers (most famously the Department of Defense). Logsdon notes that bringing DoD onboard levied specific requirements on payload sizing and cross-range capability (i.e., the ability to move the landing trajectory left or right of its descent path). One myth of Shuttle design is that this cross-range requirement led to the adoption of the large “delta-wing” configuration of the orbiter (increasing its mass and cost greatly). But NASA engineers had decided that this configuration helped to alleviate thermal issues during reentry and would have gone to something similar anyway.

The chronology and description of this decision process is valuable and I learned much from this section. The principal weakness of the book is in its conclusions, which are all too clearly colored by Logsdon’s disdain for Nixon. Logsdon levies the blame on Nixon’s shoulders for not setting a visionary, exciting space goal for the nation. But it is “perfectly clear” from his own narrative that there was no mood in the country for anything more than Shuttle. Moreover, you will search the book in vain for any detailed discussion of the opinions and influence of liberal Democrats in Congress regarding the space program (which were highly negative in the extreme). People like Senate Majority Leader Mike Mansfield, Senators Proxmire, Mondale, and most notoriously (the brother of JFK) Ted Kennedy, all made negative and disparaging statements about the space program around the time of the first Moon landing. Nixon’s presidency spanned six Congressional terms, all of which transpired under majority control of both houses of Congress by the Democratic Party.

Logsdon criticizes Nixon for using the space program as a political pork barrel and vote-getter, with California’s aerospace industry being a major beneficiary of the Space Shuttle program (Nixon needed to carry the state in the 1972 election). But space pork didn’t start with Nixon; the location of the NASA Manned Spaceflight Center in Houston derives from the influence of two powerful southern Democrats in Congress, Lyndon Johnson and Albert Thomas of Texas. Nixon proposed much lower space budgets than those of the Apollo days, but most forget (and Logsdon doesn’t mention) that much of the Apollo era spending went to build permanent infrastructure (such as launch, assembly, and testing facilities), assets used by all other subsequent space programs. By design, those sunk costs were never to have been repeated. Logsdon repeats the standard line that “Nixon stopped building the Saturn V” but it was President Johnson who shut down Saturn production in 1968 after a review determined that we already had the number of vehicles necessary to accomplish the goal of a lunar landing.

Logsdon concludes that the decision to build the Shuttle was a “policy mistake,” but one should consider the alternatives. Apparently, Logsdon would have favored the “small shuttle-glider” design proposed by OMB during the policy debate. What if that path had been taken? We would have found that many of the technologies needed for a full-sized shuttle were more difficult to perfect than we thought. Besides, the shuttle-glider prototype was nothing more than the current “Flexible Path” approach (i.e., get technology first, destinations and goals later). Would that have led to the building of more capability or less? Perhaps we might have gone back to the capsule and big rocket days of Apollo (as we have apparently done now), but that would have meant no space station and it most certainly would have meant no manned Mars mission (the elusive Holy Grail space program that has kept us from doing anything of lasting value beyond LEO for more than forty years).

A hidden gem in the book (page 214) deserves special mention. William Niskanen, an analyst with OMB, describes two libertarian ideas – changes he believed would inject more money into the space program and help unburden the taxpayers. One idea was to bring rocks back from the Moon and sell them to the public, using those funds to support further space efforts – a plan, while inventive, that would not have generated anywhere near enough money. Niskanen’s other idea was for NASA to get out of the launch and spaceflight business and let the private sector develop the next generation of launch capability. Then, the federal government could contract for launch services from American business. In response to this suggestion, legendary NASA engineer and manager George Low told Niskanen that “the reason for not doing it is that it simply won’t work; if the idea is to cancel the space program, this might be a way to do it.” I almost bust a gut with laughter at that passage.

Laying the blame for 40 years of perceived mediocrity in space at Nixon’s feet may be satisfying, but it’s not particularly enlightening. The reason that there was no visionary goal for space after Apollo is because Apollo was not about space – it was about beating the Soviet Union in the Cold War. Once accomplished, there was no need for any crash space program, especially one as difficult and expensive as a manned Mars mission. Thus, NASA fell back on the classic von Braun architecture: the systematic extension of human reach into space through the consecutive building blocks of a shuttle-station-moon tug-Mars mission. Shuttle was intended as the first part of an extensible, permanent space faring system; it was never meant to be the “ultimate space vehicle” but rather, the first leg of a long journey. As for money for space, 40 years of funding at less than one percent of the federal budget might suggest to an objective observer that this level of spending is politically sustainable (even if it’s not the level that space buffs would want). The corollary to this recognition is that it is our challenge to construct an approach that makes progress with such funding levels, not to whine about our belief that it isn’t enough.

Still, this new book is worth reading, with the reservations expressed above. I cannot help but think that Logsdon’s conclusions – steeped in Beltway conventional wisdom – are driven more by his opinions of the presidency of Richard Nixon than by an objective evaluation of the historical facts surrounding Shuttle development. That the development of the Space Shuttle was a “policy mistake” is his long-held opinion and certainly one way to read the record. But other readings are possible and for all of its faults, that space program of recent memory was arguably better than the one we have now. I couldn’t help but think of an image: Dick Nixon’s space program as Pat Nixon in her good Republican cloth coat; Jack Kennedy’s space program as Marilyn Monroe, seductive in a mink coat.

Posted in Lunar exploration, space industry, space policy, Space transportation | 26 Comments

Science Publishing – Some Skepticism Required

I have a new post up at Air & Space about the current scandal of fake papers being published in scientific journals, the breakdown of the peer review process, poor scholarship among some scientists and “expertise” derived from Google searches.  Comment here,  if so inclined.

You may have noticed that I haven’t been blogging here much lately.  I am busy with the manuscript of my next book, due at the publisher in a couple of months.  I’ll be back with more commentary on space policy and programs soon.

Posted in Lunar Science, Philosophy of science | 32 Comments

Yutu on the Moon and the Cost of Mars

A couple of new posts on other sites that might be of interest to the readers of this blog.

Over at Air & Space, I discuss the new science results from the Chang’E-3 Yutu rover investigations.  Comment here, if you are so inclined.

Also, Glenn Smith and I have an op-ed at Space News on the likely cost of a human Mars mission.  Comments here are welcome.

Posted in Uncategorized | 32 Comments

Fossils on the Moon?

Perhaps.   I discuss in a new post up at Air & Space magazine.  Comment here if you’d like.

Posted in Lunar exploration, Lunar Science, planetary exploration | 7 Comments

Regulating Business on the Moon

Lunar outpost under construction using 3-D printers to fabricate infrastructure.  NASA image.

Lunar outpost under construction using 3-D printers to fabricate infrastructure. NASA image.

The U.S. Federal Aviation Administration (FAA) has decided to “authorize” operations on the Moon as part of the process of granting a license for the launch of a commercial payload to space. This launch-licensing scheme affords advance federal government recognition of planned commercial activities on the lunar surface, specifying an “exclusion zone” within which other payloads would not be permitted. This decision by the FAA is heralded as a “first step” towards the specification of private property rights for the Moon.

Although much has been discussed over the past few years about mining the Moon for materials, metals, nuclear fuel and rocket propellant, all of these discussions focus almost exclusively on the technical issues associated with resource extraction, transportation and use. Little has been offered on the legal issues involved in lunar (or an extraterrestrial) mining – staking a claim. This legal vacuum exists for a very straightforward reason: no one knows the legal status of commercial space mining and planetary surface activity.

Several international treaties, the most pertinent of which is the 1967 U.N. Outer Space Treaty (OST), set the current legal regime for space activities. The OST was signed by 129 countries, including all of the major space faring nations. The treaty bans nuclear weapons in space and prohibits any nation from establishing territorial claims on extraterrestrial bodies. This formulation left open the question of private development and ownership, although the treaty states that “Outer space, including the Moon and other celestial bodies, shall be free for exploration and use by all States without discrimination of any kind, on a basis of equality and in accordance with international law, and there shall be free access to all areas of celestial bodies.

Note well – “free for exploration and use by all States…” That wording would appear to guarantee the rights of a nation to mine the Moon, extract a product, and then – what? Certainly one would suppose that this language ensures that a government facility could manufacture rocket propellant to use in its own vehicles. But does it permit a private company based in that nation to make the same product and then offer it for sale on the open market? Despite the FAA decision, that question is unresolved.

In fact, it’s not completely clear just what issue is resolved with the new FAA ruling. Certainly they can issue restrictions on American companies in regard to impinging upon the activities of another American company, say for example, Moon Express landing a vehicle near an installation of Bigelow Aerospace inflatable habitats on the Moon. But who else is obliged to observe those restrictions? International companies that launch from their own soil do not require FAA commercial licenses. Unless some reciprocal agreement is reached with all these nations, their private companies do not have to respect the access and “control zone” rights of our nation’s companies.

The situation becomes even murkier when considering the possible interactions of a private American company on the Moon and the national representatives of a foreign power. Suppose another country (e.g., China) decided (for whatever reason) to land their government-funded, military-controlled spacecraft on lunar territory that the FAA had previously “set aside” for the exclusive use of Bigelow Aerospace? Legally, the FAA license has nothing to do with China, who are not bound to observe any restrictions. When international relations are peaceful and productive, conflicts are unlikely to arise. But political situations change, sometimes at the drop of a hat, and certainly on timescales shorter than industrial development cycles.

Prime locations on the Moon – as on any other extraterrestrial object – are not limitless, and access to and use of the most desirable and valuable sites for resource prospecting and harvesting may be contentious. In terms of water production (rocket fuel and life support consumables), ideal sites are in zones of enhanced duration sunlight (“quasi-permanently lit areas”) near the Moon’s poles, proximate to permanently shadowed regions (deposits of water ice). At such locales, electrical power can be continuously generated in order to extract the nearby water ice. There may be only a few dozen zones where initial ice harvesting facilities may be operated with reasonable efficiency (more prospecting data will give us a better picture). If this turns out to be the case, then who gets the rights to produce the product? What constitutes staking a claim? First come, first serve? Or does “might” make right?

This issue leads us to the consideration about the presence and role of the U.S. federal government in space. I have contended previously that a strong federal presence in space is necessary to ensure that our rights are established and that our values be protected and promoted. In the hypothetical context mentioned above (Bigelow vs. China), a single American company facing a determined nation-state is not likely to prevail in a manner favorable to the interests of free market capitalism. Legal recourse on Earth would be limited (more likely, non-existent) and it is also unlikely that the United States would go to war over the infringement of some corporate plot of land on the Moon – at least during the early stages of commercial space. However, if the federal government establishes a presence, it gives notice to the world of our national interests there. Such a presence makes the infringement of property and access rights of American corporations both less likely to occur in the first place – and more easily resolved if such a situation arose.

There is no reason to assume that all nations will voluntarily cooperate in space, if for no other reason than nations do not behave this way on Earth. Sometimes national rights of way and access to resources must be guaranteed by physical presence, backed up with threat of force. This is the way of life at sea here on Earth and the reason that we have a blue-water navy – not only to defend our country, but also to project power and protect our national interests abroad. Historically, the navy has conducted exploration and goodwill tours in peacetime, and power projection in times of tension and war. A space navy could do likewise as humanity moves outward into the Solar System.

For these reasons, I think that the new FAA letter doesn’t deal with the identified need for articulation of space property rights, but rather, seems to be a way to put off such a discussion for a later time. Ultimately, we will need to face up to our national and collective responsibilities to protect American commerce wherever it occurs. Given the risk being taken in opening up space to commerce, companies need the assurance of government’s protection of their investment. In the very near future, our theater of operations will include cislunar space. The idea that the “private sector” alone can develop near Earth space is not realistic. It remains a dangerous, unpredictable world and clear-thinking leaders will plan for future confrontations, if only so that they may be avoided. Any display of weakness will be exploited – and not to our benefit.

Posted in Lunar development, space industry, space policy | 32 Comments

The Space Program – A Modest Proposal

The Cape York meteorite, currently at the American Museum of Natural History, New York.  Get back to where you once belonged.

The Cape York meteorite, currently on display at the American Museum of Natural History, New York. Get back to where you once belonged. (Photo by AMNH)

A recent article on the status of the proposed Asteroid Retrieval Mission (ARM, or as I call it, the “Haul Asteroids!” mission) envisions a forthcoming partisan fight. The Verge article claims that the ARM, “strongly supported” by NASA, is opposed by Republicans on the Hill, with Congressional Democrats giving it only middling to tepid support. One could question the basic assertions of this piece at length, but what struck me was an unmentioned, key aspect of the ARM controversy – that NASA’s Small Bodies Working Group (SBAG, pronounced “s-bag” by those in the know), the committee of scientists who advise the agency on scientific questions and missions to small bodies such as asteroids, basically look upon this mission as irrelevant and silly. Because this community is the beneficiary of the scientific bonanza supposedly set to pour forth from this mission, this is important information.

The basic concept of the ARM is to first find a small near-Earth asteroid, collect it into an expandable bag and then attach a solar electric propulsion module to it. It will then be slowly returned to cislunar space and placed in high orbit around the Object-That-Cannot-Be-Named. Once there, this purloined space rock will be accessible for rendezvous by human crews using the forthcoming Orion spacecraft. When the crew encounters this captured and displaced object, they will hook on, chip off some pieces and return them to Earth for analysis.

What are these samples likely to tell us? We actually have an inkling of the knowledge they might provide from previous vast study of meteorites – those rocks from space that have fallen on the surface of the Earth for millennia. In fact, we may already have – now existing in the pages of the tens of thousands of scientific papers previously published on meteorites – the scientific information that the ARM allegedly will return. Talk about a knowledge revolution!

I’m at a loss to explain why one aspect of the ARM mission hasn’t been discussed in the media: seeing that advocates of the ARM think nothing about re-arranging the architecture of the Solar System for their convenience, environmental activists might object to the very idea behind the mission. We can’t get to a near-Earth asteroid with the Orion spacecraft and the Space Launch System (SLS), so let’s just drag the asteroid to us! Imagine a defenseless rock, innocently tumbling its way through space, only to be snagged, bagged, and defiled – appropriated and exploited by arrogant, human interlopers. There ought to be a law!

Then too, the SLS program has a problem. The out-years budget for NASA allows for the development of the launch vehicle and the supporting infrastructure that it requires, but no money is budgeted for payloads. This has led some agency officials to solicit possible unmanned, scientific payloads – missions that entail using large, massive spacecraft that need quick trajectories to deep space destinations. Although a few potential robotic science missions have been identified, there are not nearly enough of them to keep the SLS manifest fully populated.

These two ideas – appropriating an asteroid and a need for destinations for our new spacecraft got me thinking about finding some common ground. As I mentioned previously, meteorites have fallen to Earth for thousands – millions of years. The total amount probably exceeds several hundred thousand tons of material, of which we have only accounted for a few hundreds of tons. These former near Earth objects (NEO) came from space – their rightful domain before being captured by Earth’s strong gravitational pull. And as we’re sentient beings of conscience, we should both desire and strive to restore the natural balance of things in the universe, as we understand them to be.

So, I propose that we send the Earth’s collections of meteorites back whence they came. We should round up every meteorite in public ownership (the Curatorial Laboratory at the Johnson Space Center in Houston has hundreds of kilograms of meteorites collected in Antarctica) and load them onto SLS rockets. The abundance of meteorites currently residing unnaturally in museums could be confiscated, along with the NASA collection. Although many meteorites are privately held, an international law could be passed to outlaw their ownership and these too could be added to the launch manifest. The law could further decree that any future meteorite landing on Earth is the property of the universe and will be returned hence with dispatch. Earth will be deemed a no-meteorite-go-zone, kept clean of these foreign bodies, with all endangered space rocks released back into their natural habitat. Kumbaya all around.

By returning these rocks and boulders to interplanetary space, we’d have a multitude of “exciting” destinations for the Orion spacecraft and SLS launch vehicle while biding our time until our “ultimate” mission to Mars. It is the right thing to do for these rocks. After all, it’s not their fault that they ended up here on the Earth – thoughtlessly swept up by the gravitational monster that it pleases us to call our home planet. We could send some of the meteorites into low Earth orbit. There, they will provide endless hours of training and amusement for the crew on the International Space Station, keeping them on their toes to maneuver the station in order to avoid collisions (Look lively, m’lads!). Other meteorites would be sent out into deep cislunar space, including locations near the Object-That-Cannot-Be-Named. Once in space, these free ranging beauties will provide a wide variety of targets for human missions.

This simple but innovative and sustainable mission plan accomplishes several objectives simultaneously. We create new payloads for the SLS launch vehicle, thus avoiding the embarrassment of developing a new heavy lift vehicle with nothing to put on top of it. We create a variety of new target destinations for future missions, thus providing years of top-notch human spaceflight spectacles, as each previously studied meteorite is approached, encountered, studied and sampled again, this time within the confines of its own natural habitat. We correct a great planetary wrong by putting the Solar System back into its original, natural order. And we’ll rest easier, knowing that we have ensured a vibrant, continuing space program while at the same time “giving back,” as the currently popular phrase would have it. There will always be meteorites needing rescue to return whence they came. Here is a true mission into the future – appropriate for our time and one that will elevate our civil space program for decades to come.

Posted in planetary exploration, space policy, space technology, Space transportation | 33 Comments

“Overthrowing” Science?

The clockwork universe -- "overthrown" by relativity? (From Einstein and Eddington, BBC)

The clockwork universe — “overthrown” by relativity? (From Einstein and Eddington, BBC)

I enjoyed watching a couple of movies during the holidays. Covering important historical events, they detailed the back stories behind major scientific developments.

Einstein and Eddington, a BBC production from a few years ago (available on YouTube), is a dramatization of one of the most famous scientific experiments of the last century. The 1919 British expedition to Africa led by Sir Arthur Eddington, to observe and record a total solar eclipse, was undertaken to test Albert Einstein’s General Theory of Relativity.

The Imitation Game tells the story of Professor Alan Turing’s involvement in cracking Enigma – the German coding device used to encrypt the military communications and operations of the Third Reich. This successful, British top-secret effort by a group of scientists and cryptologists, is credited with saving many lives and for shortening the duration of World War II considerably.

While these two films are interesting and reasonably well told, what caught my attention were certain ideas implied by the narratives. Viewers need to be cognizant of history – and artistic license – when a filmmaker uses the descriptor “based on a true story.” In both cases, the story lines got some things wrong. In Einstein and Eddington, it was implied that the General Theory of Relativity (tested and validated by Eddington’s observations) “overthrew” Newtonian mechanics (the physics that we all learn in high school). At the end of The Imitation Game, we are told that “Turing’s Machine” (the collection of relays and rotating drums that was used to decode the Enigma messages) is “known today as the computer.” This statement implies that Turing invented the modern computer. I think that both of these “conclusions” (as they seem to imply) are wrong and do a disservice because they reflect a misunderstanding of how science works and the meaning of scientific knowledge.

Science is the process by which we explain nature. It involves not merely expensive laboratory equipment, white lab smocks and wild hair on absent-minded academics, but in reality, it is a way of thinking about problems. We observe the world and devise explanations for phenomena. Usually, most of these “guesses” are wrong. The most common misunderstanding about science is that it is a collection of immutable knowledge. Actually, it is a collection of the best explanations that we have at any given time. Any scientific explanation is subject to change, given enough compelling evidence. Researchers must keep an open mind about scientific explanations (called hypotheses), even those that have been long accepted by most workers (the scientific “consensus”).

When a hypothesis has been around for some time and continually passes whatever tests we can devise for it, it becomes elevated to the status of a scientific theory. Note well that this meaning of the word theory is very different from its common meaning in everyday speech. In common parlance, we typically use the word theory to mean what a scientist means by the word hypothesis, which is usually no more than an opinion (informed or not). But there is a very important difference.

In science, any hypothesis must be testable. To maintain its status as a viable concept, hypotheses undergo repeated testing. A million “passings” of an experimental test mean nothing against a single failure. If a hypothesis cannot stand experimental or observational scrutiny, it must be discarded. At best, it is incomplete; at worst, it is simply wrong. If a hypothesis continually stands up over time to many different tests, it gradually becomes accepted as a theory. Good hypotheses and theories not only stand up to rigorous testing, but they make predictions about what possible future tests will indicate.

The system laid out in Sir Isaac Newton’s Principia (1687) described a mechanistic world that was predictable and comprehensible. Its famous Law of Gravitation made testable predictions, one of the first being a precise description of the timing and location of the next apparition of the 1682 comet (now known as Halley’s comet), which promptly appeared again in 1758. The Newtonian system was so thorough and comprehensive that it was thought to be the definitive explanation for the way our universe worked.

Toward the end of the 19th Century, problems with Newtonian mechanics appeared. These involved diverse phenomena ranging between the extremely small and the extremely large. Problems appeared with the classical understanding of light as a wave. The orbit of Mercury did not conform to strict Newtonian predictions. Einstein, working to explain some of these discrepancies, concluded that classical Newtonian mechanics were not wrong – merely incomplete. It was only at the extreme ranges of possible measurement (such as very massive objects like stars, and very high velocities such as the speed of light) that these discrepancies were evident. Einstein went on to develop a new system to better describe the behavior of the universe in these extremes.

The contention of the film Einstein and Eddington that Einstein “overthrew” Newtonian physics is simply wrong. General Relativity (Einstein’s name for his model) doesn’t overthrow anything – it extends mechanics into realms with which Newton had no experience. Under normal conditions (i.e., human-scale interactions with nature), Newton’s equations work just fine. Only at the very limits of observational science do we find that we need relativistic mechanics. A good example of this is the use of GPS systems to navigate cars, ships and airplanes. Because GPS satellites move at very high speeds (orbital velocity) and use extremely precise (atomic) clocks, corrections must be made for the fact that relativity predicts that time moves more slowly the faster you travel. This relativistic time correction is needed to give the meter-scale precision that GPS can deliver.

One of the most interesting things about General Relativity is that it does not replace Newtonian physics – it encompasses it. When velocities and distances are more within the realm of normal human experience, the Einstein gravitational equation reduces to the Newtonian one. Thus, General Relativity did not “overthrow” Newtonian theory – it extended it into new realms. Scientific revolutions rarely overthrow systems of thought, more typically they extend and refine our knowledge. (One exception is the overthrow of the Ptolemaic Earth-centered Solar System by the Copernican Sun-centered one.)

Likewise, Turing’s Enigma de-coding machine at Bletchley Park was not the world’s first computer. Computing machines have been built for centuries, each new one being more advanced, more powerful and more capable than the last. If any one person should be granted the “honor” of being the father of the computer, it is probably John von Neumann, whose basic computer architecture is used in every computer today. Turing certainly deserves great credit for his ideas about algorithms and computable numbers, but a “Turing Machine” is a theoretical concept, not a practical computer. The work of von Neumann built upon and extended Alan Turing’s work (whose value von Neumann fully acknowledged). Newton notably expressed the cumulative process of learning in science when he said, “If I have seen further, it is by standing on the shoulders of giants.”

Science advances incrementally (small steps that contribute to knowledge) and cumulatively (each piece adds to the larger whole). It is also supposed to be self-correcting. Scientists must accept and acknowledge the concept that scientific knowledge is constantly changing and changeable. Thus, ideas like “the opinion of the majority of scientists” or “consensus” reflect not science but our current incomplete (and likely mistaken) state of knowledge. The worst science of all twists new observations, facts and discoveries inside out to preserve the viability of some existing model. A wide variety of current popular scientific ideas (such as the origin of the Moon and global climate change) belong in this category. The attractiveness or appeal of an idea is not relevant to its validity. Scientific hypotheses must be falsifiable. If they are not, we’re just chasing our tails.

I strongly recommend both films for enjoyable entertainment and insight into how science works – just watch out for the producers’ misunderstandings of it.

Posted in Lunar Science, Philosophy of science | 19 Comments

On the Habitability of the Moon and Mars

Moon Mars cities

Humanity’s future homes? Understand the problem first. (Artwork by R. A. Smith)

After reading the comments to a question recently posed at Reddit, I’m once again struck by how quickly a serious discussion about space can fly off the rails without knowledge of basic facts and their implications. The question that was raised is “Why is everyone so eager to colonize Mars, while the Moon, with its proximity and low gravity, sits empty?” As you might expect, the comments on this question vary widely in their relevance and cognizance. I thought it might be useful to collate some of the relevant facts that must be considered in determining which body is most useful for learning the life skills of an off-planet species.

Of course, the word “colonize” is loaded with different interpretations, but in this case, I take it to mean the establishment of permanent human settlements on either world. As is so often the case, the discussion at Reddit quickly turns toward comparing the two objects in terms of their resources and surface environments. While some of the comments are well informed, many misconceptions about the properties of both objects are readily evident – both confusing the casual reader and inhibiting the discussion.

Humans need raw materials, wherever they live, including light elements (e.g., oxygen, hydrogen and carbon (see page 4 of this paper), usually associated with the needs of life support, such as air, water and food) and heavier elements (needed to make things, including structures and machines). Energy is required to process this material into whatever form is required. Fortunately, all of the objects of the inner Solar System are rich in materials, although their concentrations vary from place to place. The critical controlling factor on whether a place can be inhabited is the availability of a reliable and continuous source of energy.

There is no “Second Eden” in our Solar System. Wherever people travel in the space around our Sun, they will have to create a protective environment to shield their bodies from the harsh conditions that they encounter. Because we are talking about not merely exploring, but rather living off the Earth, we need to be able to make what we need to survive from locally available materials. Naturally, some places are easier to settle than others, but when deciding which locations have more merit, it is important to fully understand all the requirements for habitation, not just the most obvious (albeit critical ones), such as the availability of water or the depth of the local gravity well. The key light element materials needed to support life are the so-called CHON elements (carbon, hydrogen, oxygen and nitrogen). Water supplies the middle two, but sources of both carbon and nitrogen must be found and available for harvest. After collection, we must be able to find or synthesize the substances needed, which involves a lot of chemical processing, time, and energy.

The Moon is depleted in light elements (although large quantities are present near the poles) but is well endowed in the heavier rock-forming elements (e.g., iron and aluminum). Over billions of years of micrometeorite bombardment, the lunar surface has been ground into a fine, grain-sized dust of jagged, angular fragments of minerals and glass. Moving parts quickly become immobile when coated with this talcum powder-like, abrasive dust. Future lunar inhabitants will need to mitigate these effects, as well as protect themselves from the transfer and inhalation of the local surface dust. The Moon has no appreciable atmosphere (its exosphere has a surface pressure of 10-15 bar, or about one-thousandth of a trillionth of the atmospheric surface pressure of Earth). The lack of a global magnetic field means that the lunar surface is a hard radiation environment. Both solar particles (including coronal mass ejections) and galactic cosmic rays bombard its surface. Over the course of a single lunar day (28 Earth days) at the equator, the Moon experiences thermal extremes ranging from 100° C to -150° C, while at the near-permanently lit areas near the lunar poles, the temperature is a constant -50° C. Compared to the planets, the Moon’s low gravity (about 1/6 that of the Earth) makes it a relatively easy object to access and leave (something we did successfully on six occasions, 45 years ago).

Mars appears to be richer in light elements than the Moon. We know very little about the nature and abundance of the heavier elements on Mars, but meteorites (that we believe come from Mars) suggest that its crust is made of rocks quite similar to those that make up both Earth and Moon. Thus, it is likely that iron is very abundant, and it is probable that aluminum and other metals can also be found in quantity. Like the Moon, Mars also has very fine dust, but it appears to be composed of clay minerals and thus, it is likely to be both softer and less abrasive than lunar dust. However, analysis of data from landed probes suggests that Mars dust may be highly reactive chemically (including the presence of toxic substances, like peroxides). Future Mars inhabitants will need to protect themselves from these substances.

Mars has an atmosphere but it is extremely thin (surface pressure is about 6 millibars, or six thousandths of an Earth atmosphere) and is composed almost completely of carbon dioxide. The martian atmosphere can be used to aerobrake (i.e., slow down a spacecraft during landings) but its atmosphere is not thick enough to eliminate the need for significant propulsive braking. This is a problem since the martian gravity is more than twice that of the Moon, or about 3/8 (0.38) the gravity of the Earth. Landing on Mars with heavy (i.e., human-sized) landers remains an important, unsolved issue (called the Entry-Descent-Landing (EDL) problem). The deep gravity well of Mars means that bigger, more energetic spacecraft will be required to get off the planet (and streamlined, as initial passage will be through an atmosphere that, while thin, is still significant). Mars is cold, but warmer periods occur in some areas (temperatures range from about -150° C near the poles, up to almost 20° C during summer at the equator). Although its atmosphere provides some protection, the surface of Mars remains a hard radiation environment, roughly equivalent to what is received by the equipment and crew on board the International Space Station.

On both planets, humans must be protected from the local environment. Pressurized habitats are needed and must include shielding from radiation. Such protection will likely be accomplished through the use of local material as shielding, either water (an excellent radiation protective) or local soil, requiring high-power machinery to excavate and move large amounts of material. Both Moon and Mars contain significant deposits of water. On the Moon, water is found in quantity within the permanently dark floors of polar craters. Hydrogen is also implanted on the grains of the lunar soil in extremely small quantities. Water appears to be more widely distributed on Mars, being found as vapor in the atmosphere, chemically bound in clay minerals everywhere, and in some localities at higher latitudes, near the surface as ground ice.

Energy is the critical pacing item for colonization. Wherever people go in space, they will need energy and lots of it. We must create a special environment to protect ourselves, something we get naturally here on Earth. The principal sources of electrical energy in space travel are solar and nuclear. The closer you are to the Sun, the more solar energy is available. Because Mars is about 1.5 times as far from the Sun as the Earth-Moon system, solar energy is less than twice as intense there (inverse-square law). This allows small robotic spacecraft to operate on Mars with solar panels, but solar electric, as the sole source of energy for larger vehicles and facilities (such as human habitats), is not practical. It is certainly inadequate for the amounts of energy needed for resource processing necessary to support a human colony. For this reason, credible plans for the colonization of Mars rely on the continuous operation of nuclear reactors.

On the Moon, a day/night cycle of two weeks duration (at the equator) means lunar inhabitants must survive a very long, cold night without solar power. In the past, ideas about lunar habitation have always collided with this reality, leading to a requirement of a nuclear reactor. Recently, however, mapping of the Moon’s surface found areas near the poles of the Moon that remain in sunlight almost continuously. This is possible because the Moon’s spin axis is nearly perpendicular to its plane of orbit around the Sun. This discovery makes lunar habitation much more likely. We can now envision an initial human presence off-planet without the need for the near-term development of a practical space nuclear reactor (an item that does not currently exist and will require several billions of dollars for development).

One last consideration is the distance from Earth. The Moon has the advantage of being relatively close – about three days away on typical trajectories. Moreover, as it is in orbit around the Earth, the Moon is constantly available for both arrival and departure, so a quick bug-out is always an option. In contrast, launch windows to Mars occur infrequently, on the order of every two years with current technology. Transit times (one-way) are several months in duration and do not offer easy abort options. The proximity of the Moon results in instantaneous RF communications (3 seconds round trip) while the distance of Mars means that communications between Earth and Mars have time-lags of tens of minutes.  Thus, habitation requires much more local autonomy at Mars than the Moon.  Unless the first colonists have a death wish, these issues of proximity and access must be addressed.

We know about de-conditioning of the human body in zero gravity, but we are completely ignorant of such effects in the fractional gravity the Moon and Mars. We think that problems from radiation can be minimized, but the long-term effects of living in a shielded environment are unknown. Some focus on initial access as the biggest problem, but gravity is only one factor and consideration among many. Any debate about where to “settle” in space must be cognizant of these and many other facts. Both the Moon and Mars have their respective advantages and disadvantages. The decision over where to focus our limited resources in the near term must take into account the relative abundance of materials needed, their locations on the object and our ability to access and process them into a form that we can use.

Debate is good and is to be encouraged but only informed debate is useful and essential.

Related: A comparison of asteroids vs the Moon as a space destination can be found in this 3-part series:

Destination: Moon or Asteroid? Part I: Operational Considerations

Destination: Moon or Asteroid? Part II: Scientific Considerations

Destination: Moon or Asteroid? Part III: Resource Utilization Considerations

Posted in Lunar development, planetary exploration, space policy, space technology, Space transportation | 53 Comments