So paint this across your mind:
We’ve led up to this: the Bebebebeque rebels’ transporter at ground level has exploded while linked to the half-repaired Enterprise transporter. The flare picked up every life form within a mile and scattered them throughout the Enterprise!
Picture a splash page with an inset: one-third of a page of Sunday comics showing just one scene, plus a window inset for a closeup. (I wanted one scene. Sharman says it generally looks better with the window.)
We’re in the recreation level of the Enterprise. The rec level is a park, lush with vegetation. At the moment it looks like a hallucinatory Vietnam, because kzinti and Bebebebeque and Enterprise crew are all fighting it out for control. A ravager is tearing things up too. He’s bigger and meaner than the kzinti. The kzinti are bigger than humans. The crew is generally actor-in-rubber-suit-sized but not all human. The Bebebebeque are tiny; most of them ride antigravity sleds. The perspective and orientation are all screwed up.
The window: closeup of Uhura and an anonymous Crewman, both armed, behind a covering boulder. The Crewman is telling Uhura, “My brother wanted me to help him with his wet-ranch on Midar—”
The splash page: In the extreme foreground, four little beetle-shapes are manipulating a phaser rifle as if it were a Napoleonic-era cannon. Beyond them, still close, are Uhura and Crewman, and beyond them, humans and oversized kzinti are all fighting it out in a swarm of Bebebebeque on flying sleds, dodging or running whenever the ravager comes near.
Crewman: “—but I thought it was too dangerous, so I joined the flipping Navy.”
It’s a quote from THE MOTE IN GOD’S EYE, intended as a tip o’ the hat for Jerry Pournelle…who thought I should have been working on something more productive, like whatever collaboration we were on at the moment.
A few years ago there were no triple collaborations in the science fiction field. A normal collaboration is hard enough. Why would three people try to write a book?
Well, it was a contract matter.
The contract, and the negotiations that surrounded it, were a ball of snakes. Jerry Pournelle and I ultimately contracted to write a sequel to THE MOTE IN GOD’S EYE for Pocket Books—a thing we might have wanted anyway, and never mind the extraordinary pressures; but there was a clause we would surely have crossed out. It said that Jerry and I could not work on any other collaboration together until this one was finished.
We got antsy.
Triple collaborations were not forbidden. We signed contracts for four.
THE LEGACY OF HEOROT, written by me and Jerry Pournelle and Steven Barnes, was totally successful. Steve believes that Jerry and I think like two lobes of a brain. Effectively he had one collaborator, he says, and that made it more workable.
With A LABOR OF MOLES, the third collaborator is an artist, Wendy All. The book is finished but for Wendy’s illustrations. It may reach print before the book you’re holding…but we were stalled for several years. Wendy never nagged. We’re grateful.
Jerry and I planned FALLEN ANGELS many years ago. The story line involves a heroic underground derived from science fiction fans. We even auctioned off places in the book at convention charity functions. We planned to do it for fun…and never got around to it, until the MOTE sequel blocked us too.
Jim Baen found us Mike Flynn as a third collaborator. ANGELS should be turned in before you open this book.
You’ll remember that Jerry and I wrote a sequel to Dante’s INFERNO, set in present time, as a hack science fiction writer tries to escape from Hell. You may not know that Jim Baen tried to produce a computerized INFERNO game. The authors would have been me and Jerry Pournelle and, as our third collaborator, Alex Pournelle to do the programming.
I did some work on the INFERNO game.
Alex dropped out and was replaced.
The game got as far as a limited program with maybe twenty “rooms.”
Then everybody gradually lost interest.
Me too. I had not guessed, or remembered, how repulsive is the territory of Hell. I now recall that we wrote the novel in four months, because we wanted out. Good riddance. The only thing I regret losing is the Planetarium in Limbo.
As in the book: you dive into a red giant star, or through an Earthlike planet, or dive to the surface of a neutron star and hover…no telling how many choices of star we could afford to embed. But one would have been a black hole. You dive past the accretion disk and on in. The screen tells you, “You have passed the Schwarzschild radius.” The screen scrolls up, leaving white space, and the computer locks up. You have to restart from scratch.
So we’re talking about four triple collaborations, of which three looked like lost causes. It now appears that three out of four worked. Caveat vendor.
• • •
• • •
BIGGER THAN WORLDS
Just because you’ve spent all your life on a planet doesn’t mean that everyone always will. Already there are alternatives to worlds. The Russian space station may have killed its inhabitants, and the American Skylab has had its troubles, but the Apollo craft have a good record. They have never killed a man in space.
Alas, they all lack a certain something. Gravity. Permanence. We want something to live on, or in, something superior to a world: safer, or more mobile, or roomier. Otherwise, why move?
It’s odd how much there is to say about structures larger than worlds, considering that we cannot yet begin to build any one of them. On the basis of size, the Dyson Sphere—a spherical shell around a sun—comes about in the middle. But let’s start small and work our way up.
THE MULTIGENERATION SHIP
Robert Heinlein’s early story, “Universe,” has been imitated countless times by most of the writers in the business.
The idea was this: Present-day physics poses a limit on the speed of an interstellar vehicle. The ships we send to distant stars will be on one-way journeys, at least at first. They will have to carry a complete ecology: they couldn’t carry enough food and oxygen in tanks. Because they will take generations to complete their journeys, they must also carry a viable and complete society.
Clearly we’re talking about quite a large ship, with a population in the hundreds at least: high enough to prevent genetic drift. Centrifugal force substitutes for gravity. We’re going to be doing a lot of that. We spin the ship on its axis, and put all the things that need full gravity at the outside, along the hull. Plant rooms, exercise rooms, et cetera. Things that don’t need gravity, like fuel and guidance instruments, we line along the axis. If our motors thrust through the same axis, we will have to build a lot of the machinery on tracks, because the aft wall will be the floor when the ship is under power.
The “Universe” ship is basic to a discussion of life in space. We’ll be talking about much larger structures, but they are designed to do the same things on a larger scale: to provide a place to live, with as much security and variety and pleasure as Earth itself offers—or more.
GRAVITY
Gravity is basic to our life style. It may or may not be necessary to life itself, but we’ll want it if we can get it, whatever we build.
I know of only four methods of generating gravity aboard spacecraft.
Centrifugal force seems to be most likely. There is a drawback: coriolis effects would force us to relearn how to walk, sit down, pour coffee, throw a baseball. But such effects would decrease with increasing moment arm—that is, with larger structures. On a Ring City, for example, you’d never notice it.
Our second choice is to use actual mass: plate the floor with neutronium, for instance, at a density of fifty quadrillion tons per cubic foot; or build the ship around a quantum black hole, invisibly small and around as massive as, say, Phobos. But this will vastly increase our fuel consumption if we expect the vehicle to go anywhere.
Third choice is to generate gravity waves. This may remain forever beyond our abilities. But it’s one of those things that people are going to keep trying to build, forever, becau
se it would be so damn useful. We could put laboratories on the sun, or colonize Jupiter. We could launch ships at a million gravities, and the passengers would feel nothing.
The fourth method is to accelerate all the way, making turnover at the midpoint and decelerating the rest of the way. This works fine. Over interstellar distances it would take an infinite fuel supply—which we may have, in the Bussard ramjet. A Bussard ramjet would use an electromagnetic field to scoop up the interstellar hydrogen ahead of it—with an intake a thousand miles or more in diameter—compress it, and burn it as fuel for a fusion drive. Now the multigeneration ship would become unnecessary as relativity shortens our trip time: four years to the nearest star, twenty-one years to the galactic hub, twenty-eight to Andromeda galaxy—all at one gravity acceleration.
The Bussard ramjet looks unlikely. It’s another ultimate, like generated gravity. Is the interstellar medium sufficiently ionized for such finicky control? Maybe not. But it’s worth a try.
Meanwhile, our first step to other worlds is the “Universe” ship—huge, spun for gravity, its population in the hundreds, its travel time in generations.
FLYING CITIES
James Blish used a variant of generated gravity in his tales of the Okie cities.
His “spindizzy” motors used a little-known law of physics (still undiscovered) to create their own gravity and their own motive force. Because the spindizzy motors worked better for higher mass, his vehicles tended to be big. Most of the stories centered around Manhattan Island, which had been bodily uprooted from its present location and flown intact to the stars. Two of the stories involved whole worlds fitted out with spindizzies. They were even harder to land than the flying cities.
But we don’t really need spindizzies or generated gravity to build flying cities.
In fact, we don’t really need to fill out Heinlein’s “Universe” ship. The outer hull is all we need. Visualize a ship like this:
1. Cut a strip of Los Angeles, say, ten miles long by a mile wide.
2. Roll it in a hoop. Buildings and streets face inward.
3. Roof it over with glass or something stronger.
4. Transport it to space. (Actually we’ll build it in space.)
5. Put reaction motors, air and water recycling systems, and storage areas in the basement, outward from the street level. Also the fuel tanks. Jettisoning an empty fuel tank is easy. We just cut it loose, and it falls into the universe.
6. Use a low-thrust, high-efficiency drive: ion jets, perhaps. The axis of the city can be kept clear. A smaller ship can rise to the axis for sightings before a course change; or we can set the control bridge atop a slender fin. A ten-mile circumference makes the fin a mile and a half tall if the bridge is at the axis; but the strain on the structure would diminish approaching the axis.
What would it be like aboard the Ring City? One gravity everywhere, except in the bridge. We may want to enlarge the bridge to accommodate a schoolroom; teaching physics would be easier in free fall.
Otherwise it would be a lot like the multigeneration ship. The populace would be less likely to forget their destiny, as Heinlein’s people did. They can see the sky from anywhere in the city; and the only fixed stars are Sol and the target star.
It would be like living anywhere, except that great attention must be paid to environmental quality. This can be taken for granted throughout this article. The more thoroughly we control our environment, the more dangerous it is to forget it.
INSIDE-OUTSIDE
The next step up in size is the hollow planetoid. I got my designs from a book of scientific speculation, Islands in Space, by Dandridge M. Cole and Donald W. Cox.
Step One: Construct a giant solar mirror. Formed under zero gravity conditions, it need be nothing more than an echo balloon sprayed with something to harden it, then cut in half and silvered on the inside. It would be fragile as a butterfly, and huge.
Step Two: Pick a planetoid. Ideally, we need an elongated chunk of nickel-iron, perhaps one mile in diameter and two miles long.
Step Three: Bore a hole down the long axis.
Step Four. Charge the hole with tanks of water. Plug the openings, and weld the plugs, using the solar mirror.
Step Five: Set the planetoid spinning slowly on its axis. As it spins, bathe the entire mass in the concentrated sunlight from the solar mirror. Gradually the flying iron mountain would be heated to melting all over its surface. Then the heat would creep inward, until the object is almost entirely molten.
Step Six: The axis would be the last part to reach melting point. At that point the water tanks explode. The pressure blows the planetoid up into an iron balloon some ten miles in diameter and twenty miles long, if everybody has done his job right.
The hollow world is now ready for tenants. Except that certain things have to be moved in: air, water, soil, living things. It should be possible to set up a closed ecology. Cole and Cox suggested setting up the solar mirror at one end and using it to reflect sunlight back and forth along the long axis. We might prefer to use fusion power, if we’ve got it.
Naturally we spin the thing for gravity.
Living in such an inside-out world would be odd in some respects. The whole landscape is overhead. Our sky contains farms and houses and so forth. If we came to space to see the stars, we’d have to go down into the basement.
We get our choice of gravity and weather. Weather is easy. We give the asteroid a slight equatorial bulge, to get a circular central lake. We shade the endpoints of the asteroid from the sun, so that it’s always raining there, and the water runs downhill to the central lake. If we keep the gravity low enough, we should be able to fly with an appropriate set of muscle-powered wings; and the closer we get to the axis, the easier it becomes. (Of course, if we get too close the wax melts and the wings come apart…)
MACROLIFE
Let’s back up a bit, to the Heinlein “Universe” ship. Why do we want to land it?
If the ship has survived long enough to reach its target star, it could probably survive indefinitely; and so can the nth-generation society it now carries. Why should their descendants live out their lives on a primitive Earthlike world? Perhaps they were born to better things.
Let the “Universe” ship become their universe, then. They can mine new materials from the asteroids of the new system, and use them to enlarge the ship when necessary, or build new ships. They can loosen the population control laws. Change stars when convenient. Colonize space itself, and let the planets become mere way-stations. See the universe!
The concept is called Macrolife: large, powered, self-sufficient environments capable of expanding or reproducing. Put a drive on the Inside-Outside asteroid bubble and it becomes a Macrolife vehicle. The ring-shaped flying city can be extended indefinitely from the forward rim. Blish’s spindizzy cities were a step away from being Macrolife; but they were too dependent on planet-based society.
A Macrolife vehicle would have to carry its own mining tools and chemical laboratories, and God knows what else. We’d learn what else accidentally, by losing interstellar colony-ships. At best a Macrolife vehicle would never be as safe as a planet, unless it was as big as a planet, and perhaps not then. But there are values other than safety. An airplane isn’t as safe as a house, but a house doesn’t go anywhere. Neither does a world.
WORLDS
The terraforming of worlds is the next logical step up in size. For a variety of reasons, I’m going to skip lightly over it. We know both too much and too little to talk coherently about what makes a world habitable.
But we’re learning fast, and will learn faster. Our present pollution problems will end by telling us exactly how to keep a habitable environment habitable, how to keep a stable ecology stable, and how to put it all back together again after it falls apart. As usual, the universe will teach us or kill us. If we live long enough to build ships of the “Universe” type, we will know what to put inside them. We may even know how to terraform a hostile world for the con
venience of human colonists, having tried our techniques on Earth itself.
Now take a giant step.
DYSON SPHERES
Freeman Dyson’s original argument went as follows, approximately.
No industrial society has ever reduced its need for power, except by collapsing. An intelligent optimist will expect his own society’s need for power to increase geometrically, and will make his plans accordingly. According to Dyson, it will not be an impossibly long time before our own civilization needs all the power generated by our sun. Every last erg of it. We will then have to enclose the sun so as to control all of its output.
What we use to enclose the sun is problematic. Dyson was speaking of shells in the astronomical sense: solid or liquid, continuous or discontinuous, anything to interrupt the sunlight so that it can be turned into power. One move might be to convert the mass of the solar system into as many little ten-by-twenty-mile hollow iron bubbles as will fit. The smaller we subdivide the mass of a planet, the more useful surface area we get. We put all the little asteroid bubbles in circular orbits at distances of about one Earth orbit from the sun, but differing enough that they won’t collide. It’s a gradual process. We start by converting the existing asteroids. When we run out, we convert Mars, Jupiter, Saturn, Uranus…and eventually, Earth.
Now, aside from the fact that our need for power increases geometrically, our population also increases geometrically. If we didn’t need the power, we’d still need the room in those bubbles. Eventually we’ve blocked out all of the sunlight. From outside, from another star, such a system would be a great globe radiating enormous energy in the deep infrared.
What some science-fiction writers have been calling a Dyson Sphere is something else: a hollow spherical shell, like a ping pong ball with a star in the middle. Mathematically at least, it is possible to build such a shell without leaving the solar system for materials. The planet Jupiter has a mass of 2 × 1030 grams, which is most of the mass of the solar system excluding the sun. Given massive transmutation of elements, we can convert Jupiter into a spherical shell ninety-three million miles in radius and maybe ten to twenty feet thick. If we don’t have transmutation, we can still do it, with a thinner shell. There are at least ten Earth-masses of building material in the solar system, once we throw away the useless gases.