The Starship and the Canoe. Kenneth Brower
The Promise of Our Destiny
“We can hope to survive in a world bristling with hydrogen bombs for a few centuries, if we are lucky,” Freeman Dyson has written. “But I believe we have small chance of surviving ten thousand years if we stay stuck to this planet. We are too many eggs in too small a basket.
“The emigration into distant parts of the solar system of a substantial number of people would make our species as a whole invulnerable. A nuclear holocaust on Earth would still be an unspeakable tragedy, and might still wipe out ninety-nine percent of our numbers. But the one percent who had dispersed themselves could not be wiped out simultaneously by any man-made catastrophe, and they would remain to carry on the promise of our destiny.
“This vision of comet-hopping emigrants, streaming onward like the covered wagons on the Santa Fe Trail, is perhaps absurdly romantic or fanciful. Maybe it will never happen the way I imagine it. But I am convinced that something more or less along these lines will ultimately happen. Space is huge enough, so that somewhere in its vastness there will always be a place for rebels and outlaws. Near to the sun, space will belong to big governments and computerized industries. Outside, the open frontier will beckon as it has beckoned before, to persecuted minorities escaping from oppression, to religious fanatics escaping from their neighbors, to recalcitrant teen-agers escaping from their parents, to lovers of solitude escaping from crowds. Perhaps most important of all for man’s future, there will be groups of people setting out to find a place where they can be free from prying eyes, free to experiment with the creation of radically new types of human beings, surpassing us in mental capacities as we surpass the apes.”
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The Promise of Our Destiny (Another Opinion)
According to the Tlingits, the Creator tried to make human beings out of a rock and out of a leaf at the same time. The rock was slow, while the leaf was very quick. Therefore human beings came from the leaf. The Creator showed a leaf to the first human beings, and told them, “See this leaf. You are to be like it. When it falls off the branch and rots, there is nothing left of it.” That is why there is death in the world. If men had come from the rock there would be no death.
“We are unfortunate in not having been made from rock,” people used to say, as they grew old. “Being made from a leaf, we must die.”
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Orion
The idea of a bomb-propelled spaceship began with Stanislaw Ulam, the inventor of the hydrogen bomb. He and Cornelius Everett worked the notion out in a rough way at Los Alamos in 1955. It was taken over by Theodore Taylor, a former colleague of Ulam’s at Los Alamos. Taylor was a physicist who had spent much of his career designing bombs, and who wished that he hadn’t. His gift was for the concrete. He did with Ulam’s spaceship what he had done previously with a succession of bombs; he rendered an abstract notion practical.
“Ulam is very much a man of my own type,” says Freeman Dyson. “Basically a mathematician. He’s more like me than like Ted Taylor. Ulam and I never stick with anything very long. Ted does. Ted got hold of the idea and made it a lot better. Ted designed it, understood how to do it in detail. He could organize. He got the project going, as Ulam could never have done.”
It was Taylor who gave the project its name. “I just picked it out of the sky,” he says of Orion.
Taylor, like Dyson a former student of Hans Bethe’s, met with their old teacher in 1956 in San Diego at a conference on atomic energy. Also on hand was Edward Teller, Alvin Weinberg, Marshall Rosenbluth, and other nuclear heavyweights. The conference was organized by Frederic de Hoffmann, a former Los Alamos physicist who now headed General Atomic, a new division of General Dynamics Corporation. Secrecy had just been lifted from nuclear reactors, and de Hoffmann wanted a free discussion on what might be done with them. Edward Teller had one idea. He believed that what the world needed was a reactor so safe it was “not just foolproof, but Ph.D.-proof.” Taylor and Dyson liked the idea, and they joined the safe-reactor team. They found they worked well together. They collaborated in the design of a small nuclear reactor called TRIGA, its purpose the production of medical isotopes. That was how they spent their summer vacations. Then they went their separate ways, Freeman back to Princeton, Taylor to work at General Atomic.
In winter of 1957, Taylor called Dyson in Princeton and explained Ulam’s new idea. Taylor wanted to build a ship that would blast them into space with atomic bombs. This did not for a moment sound crazy to Freeman.
“It sounded good. It didn’t frighten me. The immediate reaction of everybody is that it will blow the ship to pieces. I wasn’t bothered by that. The thing made sense on a technical level. It sounded like what we’d all been waiting for. This was an alternative to chemical rocketry that could work.”
Freeman has little enthusiasm for chemical rockets. In a rocket, velocity is severely limited by the heat-tolerance of the engine alloys. In a chemical rocket, temperature limitations hold the velocity of the ejected gas to about four kilometers per second. In a nuclear rocket the limit is about eight kilometers per second. A nuclear-powered rocket remains an inviting idea, however, in that nuclear fuel is the most compact energy source known, with a million times the energy of any chemical fuel. A lot of high-velocity human thought has gone into nuclear engines and possible ways to circumvent their temperature limitations. “Gas-core” systems would cheat by insulating the engine with a gas that, upon being heated, becomes the propellant. “Nuclear-electric” systems would use a nuclear reactor to generate electromagnetic energy and produce a jet of ions—the plasma-drive that powers much of science fiction. Plasma-drive has yet to power a real engine, but it’s a promising idea, and someday Freeman would like to give some time to it. “There’s no problem in plasma drive, except in the energy source,” he says. “It’s one of the things I’d like to build—a nuclear-electric engine for a spaceship.” A plasma-drive engine would be sharply limited in its thrust. The ship would accelerate slowly, and thus would be most valuable in long-range, unmanned voyages.
Unmanned voyages do not particularly excite Freeman Dyson. The voyages that Ted Taylor was planning did excite him. Taylor’s manned spaceship would move its crew and equipment rapidly around the solar system. It presented fewer problems to be worked out than other systems presented, Freeman thought, and he believed these could be resolved in his lifetime. In spring of 1958 he took a leave of absence from the Institute for Advanced Studies, moved his family to California, and began work on Orion. In July 1958 he wrote this manifesto:
From my childhood it has been my conviction that men would reach the planets in my lifetime, and that I should help in the enterprise. If I try to rationalize this conviction, I suppose it rests on two beliefs, one scientific and one political.
1.There are more things in heaven and earth than are dreamed of in our present-day science. And we shall only find out what they are if we go out and look for them.
2.It is in the long run essential to the growth of any new and high civilization that small groups of men can escape from their neighbors and from their governments, to go and live as they please in the wilderness. A truly isolated, small, and creative society will never again be possible on this planet.
To these two articles of faith I have now to add a third.
3.We have for the first time imagined a way to use the huge stockpiles of our bombs for better purpose than for murdering people. My purpose, and my belief, is that the bombs which killed and maimed at Hiroshima and Nagasaki shall one day open the skies to man.
The Orion spaceship would escape temperature limitations by fleeing the heat. The time during which each bomb blast interacted with Orion’s pusher plate would be reduced to a millisecond or less. The explosions would transfer their momentum to the spacecraft—blow it away—before the heat could penetrate. Common sense has the spaceship blowing away, all right, but common sense is wrong. In explaining their idea to doubters, the Orion men used the coal-on-the-rug analogy. A hot coal pops from the fire onto the rug. If you convey it carefully between thumb and forefinger back to the fireplace, you scream.