What You Should Think About Space Elevators

November 23, 2007

“When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.”

–Arthur C. Clarke

In the novel Fountains of Paradise, Arthur C. Clarke creates a vivid tapestry of one plausible future. At one point in this work, penned in 1979, the leader of a major project does research online in preparation for a media appearance alongside a pundit skeptical of his work. While Google, Wikipedia, et al. provide a reality strikingly similar to Clarke’s vision of the future, another of his predictions has not yet come to pass. Yet there are encouraging signs of a sort.

The focus of the novel is a creation comparable to a vertical railroad for purposes of hauling mass into space. With thriving colonies on the Moon and Mars, rocket propulsion was becoming prohibitively expensive and taking a heavy toll on the upper atmosphere. Everything changes when an engineer finds out about a special sort of filament that is virtually indestructible. The incredible strength of this technology makes it possible to string wires from the a hub in geosynchronous orbit to a fixed point on the surface of the Earth. Building out a rail line from that radically changed the economics of human activity in space.

In reality there are no breakthroughs in the field of indestructible filaments. Yet work in carbon nanotube synthesis offers another striking parallel to Clarke’s foresight. Experts in the field today suggest the not-so-distant future may be home to a space elevator consisting primarily of a newspaper-sized ribbon of material synthesized to possess downright astounding tensile strength. Promising leads in the field of nanotechnology could make it possible to synthesize a ribbon that would remain unbroken while stretching the full distance from a ground station to an orbital anchor/spaceport.

In the halls of power, this remains an idea far ahead of the times. Though it may be less bold than America’s push to put men on the Moon, at present federal involvement seems limited to the occasional small grant along with NASA’s decision to assign one engineer to monitor and support ongoing research. Already this ongoing research offers much promise. In particular, carbon nanotube synthesis is subject to aggressive exploration by a mix of private and public institutions. Fantastically strong materials would have obvious commercial applications.

In that area I favor more publicly funded research. It seems that having such a fundamental technology in the public domain would produce more and better economic activity than allowing it to be controlled by a single vendor. Products produced by many corporate R&D departments working with the material offer much more promise than work with the fundamentals of making long carbon nanotube lattices shrouded in trade secrecy. Yet even if that winds up being a proprietary innovation, a space elevator project could provide the kind of enormous bulk order needed to get mass production underway promptly.

Assuming there is no crippling corruption in procurement, credible estimates suggest as little as $8 billion could finance implementation of this idea. That is no small price tag, but it does come in under the cost of two months additional funding for the occupation of Iraq or less than 1/10th the resources consumed by the missile defense budget. In fact, a consortium of private investors could pull together a project like this if the technology becomes available and this application is not pursued by any major government.

Be it private or public, the end result would be an ability to lift people and freight into space and return them safely to Earth at a small fraction of the cost involved in operating a rocket-propelled launch vehicle. Vast amounts of energy required to produce vast amounts of rocket fuel could give way to a solar farm in space and a single power plant on the ground to energize carriages traversing the elevator. The journey might be slower, but it would combine much reduced cost with much reduced physiological stress — opening up space travel to a much broader range of human beings.

Already teams of academics and engineers engage in competitions to produce the most effective or efficient vehicles for climbing or descending a prospective space elevator. Since the actual material has yet to be produced, variety in the format of these competitions builds up a flexible knowledge base. When the time comes that there is an actual need for space elevator carriages, many engineers will be capable of bringing years of experience to the project.

Using existing methods, it costs thousands of dollars to rocket a kilogram of cargo into space. The most wildly optimistic estimates about the future efficiency of ordinary spacecraft are in line with the most extreme pessimistic estimates about the cost-to-weight ratios made possible by a working space elevator. If we go beyond pessimism, the possibility exists of producing multiple Earth-based space elevators, not to mention lines for lunar and Martian shipping without the use of rocket fuel. Getting ample supplies to permanent settlements on those celestial bodies, and facilitating economically significant exports back to Earth, would be a huge advance on the journey to venture beyond humanity’s cosmic cradle.

In fact, a lack of interest among Earth’s rocket science establishment leads the protagonist in Clarke’s novel to look to Mars first. Lighter Martian gravity means that a much shorter tether is required to reach from the surface to a facility in stable synchronous orbit. As in reality, the book depicts the challenges posed by one of Mars’s small moons with a transequatorial orbit. The story resolves this problem by deliberately maneuvering the span to avoid the swift little moon as it races past.

Without significant economic activity on Mars, it is a poor place to look for space elevator funding. Yet were these feats of engineering to be accomplished on both worlds, substantial settlements and real interplanetary trade could be sustained with a much smaller energy budget than any rocket-based approach would require.

For now, the space elevator remains an intriguing idea more than it is a concrete proposal. Yet it is already much more than a pipe dream. No one would be enormously shocked to encounter headlines about the successful synthesis of carbon nanotubes in a format with properties suitable to the space elevator application. It is a result many scientists are already laboring to achieve as a logical extension of existing work in that field. So long as that result has not come to pass, perhaps it is wise that our government does no more than token work on space elevator planning and development.

Yet when it becomes possible to produce materials up to the task, swift and decisive action is warranted. Whichever government, intergovernmental agency, or private conglomerate manages to get an wonder like this to function will abruptly acquire a tremendous competitive advantage when it comes to launching and collecting spaceborne mass. Both the human adventures and the economic opportunities to follow from the initial achievement could make the following decades an age of marvelous progress.

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What You Should Think About Fermi’s Paradox

October 19, 2007

“Since, in the long run, every planetary society will be endangered by impacts from space, every surviving civilization is obliged to become spacefaring — not because of exploratory or romantic zeal, but for the most practical reason imaginable: staying alive.”

–Carl Sagan

It was not so long ago that the only explanations for what can be seen in the night sky were fictions produced for the sake of religious narrative. Some ancients were able to infer the Moon to be a distant sphere. Galileo studied the moons of Jupiter in some detail. Soon classical mechanics, a realm of physics that provides a basic understanding of everything from billiard balls to orbital trajectories, would unfold in part from the observations made through early telescopes.

Today no serious modern thinkers subordinate science to faith in the quest to understand the universe beyond our homeworld. We have found that the Sun is the most common sort of luminous object in this decidedly large galaxy. We know the Milky Way is bigger than average because we have come to photograph and study a diverse assortment of galaxies all around us. As it becomes evident that extrasolar planets are no freak occurrence, it also becomes evident that the cosmos features an unthinkable amount of real estate.

Pioneering nuclear physicist Enrico Fermi posed a question inspired by an understanding that our celestial home is not unique. If the universe contains countless worlds, a fraction of which may resemble our own, with a fraction of those producing life and a fraction of those leading to intelligence, then why has there not yet been any verifiable communications between an alien civilization and our own? Fermi’s thinking on the subject held that the lack of such encounters was a compelling argument against the existence of extraterrestrial intelligence.

Some scientists are quick to point out that “absence of evidence is not evidence of absence.” Though the argument has seen some application here, it takes a form Carl Sagan characterized as “appeal to ignorance” in his Baloney Detection Kit. Santa Claus, Invisible Pink Unicorns, Flying Spaghetti Monsters, etc. could all be defended based on the idea that a lack of reliable proof they exist does not provide any argument to believe they do not exist.

On the other hand, Sagan personally seems to have been strongly inclined toward the belief that other intelligences have evolved naturally in our universe. An appeal to ignorance should be disregarded on its own, but that does not justify disregarding other considerations. A North Pole compound where elves handcraft millions upon millions of toys seems unlikely because the Arctic has been extensively surveyed. By contrast, the capacity to survey worlds beyond our own solar system is still extremely limited.

Fermi had a point when it came to the fact that no overt relations have ever been established between humans and extraterrestrial beings. Yet does this point rest on entirely sound assumptions? When it comes to life from beyond our galaxy, physics poses some significant challenges to human contact. For one, galaxies themselves are so large, it is difficult to imagine a need that could only be fulfilled by reaching for a distant one. Then there is space itself. Not only are galaxies orders of magnitude farther apart than star systems, but the fabric of the universe constantly expands. On the scale of intergalactic travel, this creates an effect that makes a journey through space grow longer while it is underway.

Barring bold assumptions in the manner of “warp drive” or “hyperspace,” inhabitants of our galaxy may well be completely isolated from meaningful interaction with inhabitants of galaxies that are not cosmic neighbors to our own. On the other hand, our own galaxy is obviously not remote from itself. Interstellar distances are vast, but cosmological expansion has a trivial effect on the scale of journeys to and from millions of stars in the nearest 1% of our galaxy. Intergalactic civilizations require capabilities so far from current human understanding that meaningful speculation is difficult. Intragalactic civilizations are another matter.

One estimate, based on recently elevated energy prices, puts the price tag at $40 billion just to produce the power to propel an ark with a hundred colonists to a nearby star system. Actually constructing such a vessel and sustaining the lives of its crew is beyond the technology of today, but it is not so far beyond present limits that speculation is meaningless. Sagan is among many to have noted a remarkable coincidence. After billions of years of life on Earth, the rapid rise of intelligence and technology reveals the means to destroy our own habitat and the means to reach out to other worlds, with both prospects emerging in stunning historical proximity.

The ability to span interstellar distances is something of an awesome power. Is it really sound to assume that beings with such knowledge and means at their disposal would gain much from dealing directly with human beings? I’ve always thought it was a peculiar assumption, born of the jet age and the earliest space exploration efforts, to think that alien vessels would be prominent, or even visible, spectacles. Scientists headed into the bush to learn about the behavior of other species on our world will often use effective concealment, in order that their presence not change the behavior of subjects under observation. It would only take a fairly small technological edge to approach the study of humans in such a way as to leave no unambiguous evidence of the effort.

As the Sun is a common sort of star, systems with similar material composition are also likely to be common. Basic material needs may or may not ever be relevant in the context of interstellar shipping. If they are, surely it would be simpler and safer to harvest material from relatively inert orbs than one teaming with complex biology. Conspiracy theories and government secrecy leave the question of alien artifacts found on Earth so cloudy as to be best avoided in serious discussion. On the other hand, the extent of surveillance we conduct in our own solar system leaves all manner of prospective hiding places for listening posts or even traffic hubs. Pluto’s recent reclassification demonstrates the limits of what we actually know about celestial objects in our own proverbial backyard.

One exciting development in the field of astronomy involves interferometry. New technologies make it possible to deploy networks of telescopes that yield some visual details as if the network were a single lens with a diameter defined by the distance between those telescopes. With existing methods, it would be possible to deploy a space-based telescopic network with the capacity to directly image planets around other stars. So far study of extrasolar planets has been extremely limited — many discoveries do not go beyond observations of gravitational tug exerted by a star’s planetary companions, and the rest rarely go beyond analyzing the chemical composition of a planet as the smallest hints of reflected light are captured.

A global interferometer network, peering into the void with a virtual eye bigger than our own planet, could take clear pictures of these distant worlds. Would we find signs of biological activity (like the patterns of green evident on our own world?) Might we even find signs of technology (like the patterns of light evident in a night-side viewing of Earth?) These are questions that can be answered in the lifetime of most readers, provided there is political will to do it.

Until our understanding of distant worlds is improved in such a way, we remain in the dark about some details that might better frame Fermi’s paradox. Perhaps it is ultimately a question best answered with questions. Is it arrogant to think we are so accomplished or interesting that alien starships would have cause to make Earth a popular port of call? Might an existing interstellar authority maintain isolation for certain beings (or habitats) in the interest of allowing a natural rise from primitive biology to galactic citizenry? Could our lack of global political unity leave outsiders reluctant to risk actions that might contribute to such abominations as warfare?

As far as has been confirmed, we remain alone in the universe. Yet as far as we know, that seems an implausible guess. Given how common main sequence stars and extrasolar planets seem to be, it would be puzzling if none had given rise to a race of cosmic cohabitants. The fact that no credible individuals claim to possess E.T.’s phone number is a far cry from proof that there are no extraterrestrial civilizations.

We are only on the brink of looking deeply enough into space to lock down many crucial unknowns in speculation about the probability of such civilizations. Perhaps we are still a long way from looking deeply enough at our own political and social structures to be fit companions for a more enlightened form of life. Whatever the underlying reality may be, this is an area of contemplation that does much to put everything else in fresh perspective.


What You Should Think About Human Space Exploration

October 5, 2007

Treading the soil of the moon, palpitating its pebbles, tasting the panic and splendor of the event, the feeling in the pit of one’s stomach, the separation from terra . . . these form the most romantic sensations an explorer has ever known.”

–Vladimir Nabokov

I was just about to embark on “What You Should Think About Torture” when I paused to reflect on this project so far. Much of my focus has been on social and political problems. At times it can be pretty dark stuff. Thus I felt like establishing a tradition of positive themes for readers headed into the weekend. So Arthur Miller and the Spanish Inquisition will have to wait while we look to the heavens.

Few issues offer a better challenge to radical libertarian orthodoxy than nationalized space exploration. Though we know catastrophic impact events do happen, and in theory some other cosmic events could imperil us, death by astronomical hazard is, well, astronomically unlikely. The survival imperative does not apply directly to this matter. Outside that realm, the sort of people enamored with the phrase “President Ron Paul” tend to stand against government activity on principle.

Some will bolster this stance by focusing on the virtues of privately funded space ventures. All the hoopla surrounding the Ansari X Prize reveals how warped this thinking can become. Yes, the effort from Scaled Composites achieved suborbital flight for a fraction of the cost of a shuttle mission. A slight brush with space is also a fraction as useful as deploying maneuverable vehicles with the capacity to reach high orbit. Then let’s not forget the giants providing the shoulders upon which Paul Allen and Burt Rutan now stand. To hear the “privatize the sidewalks” crowd talk of this achievement, you’d think the winning team acted alone to take humanity right from the Bronze Age to the Space Age.

By no means do I wish to imply that there is no role for private endeavors in space. Corporate-government partnerships accomplished wonders in fields like relaying telecommunications and prospecting for resources by means of satellites. As relevant capabilities, with particular emphasis on deploying launch vehicles, become attainable goals for private entities, responsible exploitation of space should be encouraged. For that matter, the right breakthroughs at the right time could make possible a private space elevator before any government shows the initiative to make use of those same breakthroughs.

Still, it remains on the shoulders of governments to conduct exploration for its own sake. Microchips, weather satellites, and freeze dried food were not the ultimate goal of early space exploration efforts. Yet technological spin-offs like those have given the civilized world far greater benefits than the cost of assorted public space programs. It is just the sort of progress Wall Street would never fund. The influence of capital markets drives corporations to become ever more myopic. Most privately funded pure research has been phased out in order to focus more resources on R&D structured to produce specific ways of generating new revenue in a relatively narrow time frame.

Publicly financed space exploration creates one of those increasingly rare avenues of progress in which bold efforts to overcome enormous challenges will tend to produce a steady stream of useful discoveries. Because the nature and timing of these discoveries does not fit neatly into short term plans, it does not fit into a model of corporate operations dominated by quarterly thinking. More to the point, these innovations occur precisely because great minds are focused on great achievements that have nothing to do with commercial goals.

No doubt money is a powerful motivator. Yet Sputnik and Mir give us history to verify that breathtaking achievements can follow from other motives. A sound economy should find ways to harness the powerful force of human greed. Yet it is a dangerously unsound economy that harnesses only that force while neglecting all others. Ultimately, it could be that the greatest of all the secondary benefits provided by space exploration is human inspiration. In government agencies around the world, this inspiration serves to motivate excellent work from teams of brilliant thinkers who do not necessarily dedicate their lives first and foremost to personal enrichment.

Yet the inspirational value of space exploration goes far beyond this role of encouraging brilliant science and engineering work. Young people may be more dedicated to wholesome pursuits as a function of aspirations generated by space programs. Educators benefit from more compelling material to exploit in striving to engage student interest. Even people who do not now nor ever will endeavor to do relevant work can draw much inspiration from achievements in the heavens. Think how the Apollo Program instilled pride in all Americans, and perhaps to some degree in the entire human race.

Today the future of space exploration is in flux. China has embarked on a credible initiative to place human explorers on the Moon. Russia is revitalizing its space program with an eye toward manned flights to Mars. The United States also has a bold initiative intent on returning to the Moon, then reaching Mars. However, it is plagued by a ridiculous mismatch of overreaching Presidential mandates and insufficient funding. Add to this the dysfunctional web of autocratic nepotism that makes being politically connected more important than having sound designs or competent management.

Discouraged by unrealistic goals and outlandish technology proposals, it is only natural that American leaders in the field of space science might suggest turning away from human exploration altogether. Getting a few human bodies into space is no big deal, but taking along life support enough for something like a mission to Mars is an extremely big deal. Innovations in computing make it possible for probes and other robots to act with much of the autonomy that makes human explorers useful on a mission. There is no substitute for subjective human observation. Yet, when it comes to gathering samples, taking measurements, and other strictly empirical work; it is often much easier to develop and deploy a robotic method than it is field and equip personnel intent on the same tasks.

With that in mind, the coldest and most calculating rational approach would suggest you should think manned space exploration is a relic of the time before advanced information and automation technology. Yet I do not believe that is the correct conclusion to reach. In this area, I believe it is unreasonable to adopt the coldest possible view. Public morale, national pride, and international goodwill are all real phenomena that tend to be accompanied by real economic and social benefits. One area where a team of NASA robots cannot compete with a team of NASA astronauts is public relations.

Far from a frivolous distraction, the messages of hope and possibility space exploration achievements generate can be uplifting to people from all walks of life and all nations of the world. Any two months of full scale military operations in Iraq require expenditures greater than the entire annual budget of NASA (and some of NASA’s own budget is consumed by service to military projects.) It may not be cheap, and it may even require some political reform, but I believe the social and cultural consequences of continued manned space exploration alone justify the cost. Factor in the likelihood of great inventions falling into the public domain, and we have ourselves a form of stimulus spending that positively stimulates our economy while also stimulating the best aspects of human nature itself.