On the Reasons for Spreading to Space

Paul Gettings

Introduction
Why go to space?
How to get there
- Engines
Conclusion
About this document ...

Introduction

Outer space, that vast black void surrounding our little blue-green world, has captured the imagination of humans since before recorded history. Originally the sole domain of gods and monsters, it has recently also become the (temporary) home of ordinary humans. In the last half of the 20th century, humans achieved the ability to touch the sky, and roam among the great deeps with their gods.

Outer space represents the only limitless frontier; any world is finite, albeit very large. Space, while possibly finite, is so vast that the time when humans occupy it all cannot be forseen. A billion billion suns blaze in the dark voids, and it will take many, many aeons for humans to reach and settle them all.

As a limitless frontier, space has promise and rewards beyond the wildest dreams of history, and challenges to match the rewards. There is no more hostile environment known. There are no distances on Earth which come within orders of magnitude to the routine distance between planets, much less stars. To those who overcome these barriers, the rewards are great; fortunes will be made, and history altered, by those who step forward and continue the exploration of the limitless frontier.

For the forseeable future, humans will be limited to this solar system; the distances to the nearest stars are too far for our technology. But the solar system holds 9 worlds waiting for the imprint of humans. Some, such as Pluto and Jupiter, are not readily usable. Others, such as Mars, are plausible as planets which might one day be able to support humans without domes and space suits. Still, the system of Sol holds more resources and room than all the requirements of civilization for many, many decades. There are minerals of incredible purity in the asteroids, volatiles bound in the crusts of dead worlds. For anyone who can reach the resources, and extract them, there are supplies for decades of unrestrained growth.

This paper sets out a simple goal: to persuade the reader why humans, as a public or private venture, should expand off our little world into the dark vastness of space; and explain how the first steps of massive space exploration and exploitation might be done.

Why go to space?

Space is big, hostile, uncaring, and vast beyond belief. Why should enormous resource be poured into launching people and equipment into space, rather than improving life here on Earth? There are several reasons, each compelling in it's own right, and unassailable when taken together.

Protection of the species - Humans are the only known sentient, tool-using species. As such, we are the only species known which has the possibility of taking an active role in preventing extinction of ourselves. There have been large asteroid impacts, and other cataclysmic extinctions in the past, and there will be more in the future. Humans might survive a massive asteroid impact through industry, hydroponics, and hardened shelters. Humans can definitely survive massive asteroid impacts, nuclear wars, lethal plagues, etc. by spreading to many worlds, each self-sufficient and containing millions.
Protection of the Earth - Of the worlds known to humans, only Earth has indigenous life. This may be unique for a large portion of the galaxy, if not the universe. Human occupation, and our drive for always-improving qualty of life, is hard on the resources and ecosystems of Earth. Even with perfectly efficient and clean energy sources, complete recycling, and such, humans still represent an enormous impact and pressure on ecosystems. Moving much of the population off Earth provides a fool-proof method for relieving this pressure. Earth can, given time, recover to be untrammeled wilderness while the industry necessary for high quality of life is done on worlds where there is no life to damage.
Limitless resources - Earth is finite; no matter what argument is made about the size of a given resource (oil, iron, wheat, etc.), all resources are finite. Moving into space takes these resource limits, which civilization is beginning to bump into, and pushes them far, far into the future. There is more metal and volatile elements present in the crusts of moons and asteroids than has ever been used or conceived on Earth. While still finite, the resource limits go from visible to beyond comprehension, as they were at the beginning of civilization. Note that there will likely again come a time when the resource limits of Sol become a limit; then either humans must stop growth, or expand to new stars.
Exploration and Growth - Humans have always wondered what is beyond the next hill, or behind the lights in the sky. Curiosity about the world is a defining trait of complex life. How the unverse works, and what there is kicking about in it, are two of the fundamental questions of all religion, and the fundamental reason for the development of science. Exploration of space, starting with the worlds of Sol and expanding to other stars, is the ultimate expression of our curiosity and drive for knowledge. There is no frontier as vast, untamed, or unknown, as that of space.

For one or all of these reasons, humans should pursue the exploration and exploitation of space with every resourse possible. Massive, cheap, space travel will not solve all the world's problems, but it will solve many of them.

All problems on Earth can be classified as either a problem of resources, or one of philosophy. Space can solve any problem of resources - there are plenty of resources and volume to make nearly any manufactured good nearly free.

Philosophical problems, including political systems and orientations, cannot directly be solved by space exploitation except for ones which are solved by the removal of one side. With many worlds unclaimed by any life, various political groups that seek a homeland of their own can be ceded a planet, or large portion of a planet, to call their own. Relations between planets and colonies are no different than relations between nations on Earth. Hence, space exploitation will not put an end to war and strife, but it can make war less common; how many wars are the result of resource inequity? How many wars can be prevented when most raw resources are nearly free to anyone?

This should not be taken to imply that immediately after the settling of the first colony off-world, political quarrels and wars will come to a screeching halt. More likely, once space begins being exploited, there will be strife and chaos over who can explore and claim portions of space, who owns the resources found off-Earth, etc. After being settled, possibly through violence and war, these problems can lead towards a time when resources are no longer the cause of such conflict.

How to get there

With the U.S. Apollo program in the 1960s and '70s, it was shown that relatively simple technology could get humans to space, and return them safely to Earth. This technology, and much more, that cost trillions of dollars to develop and build in the '60s, can be found on the commercial market today for a tiny fraction of the original cost. Technology is now so cheap, that groups of individuals (and even some particularly dedicated soloists) can conceive of placing humans in orbit, or reaching the near planets (the Moon, Mars possibly, etc.). Government or commercial funding could get the job done much faster. All that is lacking is the will to go.

NASA, the foremost space agency in the current era, is in the grips of a deep crisis, whether or not they acknowledge it. NASA, during the Apollo program, was the dream job of every budding engineer and scientist. NASA tackled the impossible jobs ("put a man on the Moon within the decade"), and did the coolest projects (robot explorers of Mars) for the shear purpose of making it happen. Money was not the concern, political ambition was not the concern; getting the impossible done was the only concern. Over time, this has shifted, and now NASA is seen as being a giant bureaucracy where little happens, and many promising projects are done without the consent or support of the establishment. NASA has lost its' image of being the place to work for aspiring engineers and scientists. They lost this image on the day they decided not to pursue manned exploration of space. Why this decision was made is irrelevant.

Manned exploration is the only task which is both seemingly impossible, and yet attractive to everyone. Watching a robot rover wander over the surface of another world is nice, but it is no comparison to watching a human, real and alive, walking on another world. The impossible captures the imagination, and becomes the dream of the people.

Since NASA, as a government bureaucracy, cannot decide to re-establish the manned exploration of space (Congress doesn't believe it to be worth the cost), it is up to the private sector to lead the way, possibly with government help. NASA still has large budgets for research, and many talented engineering teams. Government-sponsored and/or conducted research can help the private sector take those all-important first steps into space.

For private ventures into space, there must be an economic return. The likelyhood of a group of very wealthy investors founding an organization dedicated to the peaceful, public exploration of space is very unlikely. It is, however, the ideal case.

Return on the investment to reach space can come from several areas:

Power - Power generation in space can be done without environmental concerns, and solar panels can gather at least 10x the power as on Earth. This makes power generation possibly a very lucrative enterprise. Initial estimates of being able to generate all the world's energy needs for $0.02/kW-hr depends only on halving the current cost per kilogram to orbit.
Manufacturing - Manufacturing also need not worry about contamination or other environmental concerns. But, there is also potentially a large class of materials which can only be made in low or zero-gravity conditions. This cannot be achieved on Earth, but is easy in space. Once setup, a factory on the Moon would have ready access to any resource in the Moon's crust. Shipments from off-Earth factories to Earth will most likely be down a gravity well, and hence need very little fuel; shipment from the Moon to Earth is much, much cheaper than from the Earth to the Moon.
Tourism - Once outposts are established with cheap transit between Earth and off-Earth locations, tourism can become a non-trivial revenue source. However, tourism will likely only be significant once a large presence in space is established.

All possible revenue streams require large investments of capital to achieve the first dollar back. Setup of a power generation system on the light-side of the Moon, complete with transmission satellites and ground stations on Earth, would take $\sim$ $200 billion. This is a large, but not impossible, number for private ventures to raise. The trick, then, is to create an organization which can convince the many investors required that the risk of their money is worth the reward.

Engines

The risk of being the first to space can be reduced to a single area: propulsion. Propulsion of spacecraft is incredibly crude, and remarkably inefficient. Chemical rockets, invented by the Chinese before 1300 AD, are still the only available method of lifting and moving large cargos among the planets. Attempting to establish a power-generation or manufacturing industry on the Moon with chemical rockets is possible, but a sharply limited vision.

The guiding vision of this document, is that access to space should be like air transport on Earth; cheap, ubiquitous, and easy. There is no point on Earth which cannot be reached by aircraft (perhaps a charter one). Similarly, there should, in time, be no place in the solar system which cannot be reached by spacecraft. Chemical rockets cannot create this vision. Travel to Mars, much less the outer planets, with chemical rockets, is akin to being trapped on an old windjammer ship; travelling across the globe took months, not hours.

Hence, the real source of risk in a private space venture, and the remaining engineering problem to be solved, is that of propulsion. With chemical rockets, moving material from Earth to a target, and back, is expensive and limited. This makes launches dangerous, expensive, and hence risky. Outposts must have many months of supplies, in case a launch fails, and launches must be carefully placed and scheduled to take advantage of weather, orbital alignments, etc.

Assume the first private venture to space solves the problem of propulsion; the corporation designs, tests, and builds a plasma drive system using thermonuclear power cores and water as the propellant. Reaction mass (water) is heated to plasma (100,000 to 1,000,000 K) with masers, and the plasma vented down a rocket cone (magnetically shielded of course). The resulting thrust is many thousands times more than a chemical rocket with similar fuel consumption. Hence, much less fuel, or much more mass, can be lifted per launch. The fuel is water, which can be obtained from many of the inner and outer planets or moons.

With such a propulsion system, it is conceivable to thrust continuously to a target at greater than 1g. A trip to Mars, instead of taking months, takes days. The outer planets are now accessible within weeks. With a nearly constant 1g thrust, the spacecraft has artificial gravity. The enormous power requirements of a plasma drive mean that the relatively tiny power requirement for a magnetic shield is easily met; crews need no longer fear the solar wind and its' terrible radiation. The spacecraft is not dependant on gravity assists, solar panels, or complex chemical fuels. A spacecraft could refuel from nearly any body in the solar system, making it vastly harder to strand or lose a spacecraft.

The risk of launches is greatly reduced, as the spacecraft does not need auxiliary fuel or boosters to reach orbit; spacecraft would become like aircraft - they land at spaceports, refuel, exchange cargo, and launch without external assistance. Launches can be anywhere, in any weather. Special orbital windows are widened or eliminated, as a spacecraft can achieve orbit with the main engine alone, hold positions for days or weeks, and burn from one planet to another without gravity assist or complicated flight plans. Outposts need not have such enormous stocks on hand, as the chance of being totally isolated is dramatically reduced.

Computational power is so vastly improved compared to the Apollo era, that ground control need only be for landing and takeoff, like the air traffic controllers at airports on Earth. Crew and computers can analyse positions, troubles, and flight paths on the way, without needing a ground base to compute and evaluate changes. This makes spacecraft more robust and independant, which allows for more spacecraft to be in operation at any time. Space is so vast, that collisions between spacecraft anywhere but at ports is extremely unlikely; radar and plasma propulsion solves this problem immediately anyway.

Conclusion

So, the goal to reach is to develop and produce such a plasma drive. The enormous risk, and money, involved in a venture to space, is all in propulsion. Solve propulsion, and the other systems of a spacecraft are almost available off-the-shelf, at very small risk and investment. Therefore, all the money, research, and manpower should be spent to solve the problem of propulsion. This is a hard problem, with many engineering obstacles. There is no reason to believe that it cannot be done; this is an engineering challenge, not a scientific one. Sending men to the Moon was an engineering challenge, of similar scope and difficulty to our problem of propulsion. Money and political will solved the Moon; it can do the same now.

The prize for the first group to solve the propulsion problem is great: conquest of space. This is a prize that is worth hundreds of billions of dollars, and years of effort. It is a prize that would revolutionize the world. It is the greatest prize in history, for it promises limitless resources and room. All that is needed is the will, ability, and money to assemble a team, and make it happen.

About this document ...

On the Reasons for Spreading to Space

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Paul Gettings 2003-08-06