"From Macrostructures Engineering: Progress Report" is also available as scans from the Lunacon 1980 Program Book.
Twelve years ago I spent a week in the Bay area south of San Fransisco. There were two fan gatherings, and in between I guested with Ed adn JoAnne Wood. Incredible place. The guest room was ten thousand books, floor to ceiling, precisely enclosing a bed and a desk. I tried to close the door the first night, and all the books started to topple on me. JoAnn came running. "You didn't try to close the door, did you?"
That first night was the first time I tried to describe the Ringworld to a fannish gathering. I was lucky. One of Ed's books had the correct formula for angular momentum. If I hadn't looked it up that afternoon, I would have made a fool of myself.
Ed thought I had.
"You stretch the mass of Jupiter into six hundred million million miles of area and you'll put your foot though it. It'll be as thin as typewriter paper!" he told me after the meeting. Not having the math handy in the back of his car, I simply told him it wouldn't. He said it would, I said it wouldn't. He ... well, I wonder if he's convinced yet.
There was another fun moment before the book reached publication. My wife and I were driving Chip Delany to the airport. He asked what I was working on. Some antic whim led me to begin describing the Ringworld ... without mentioning its size. Finally he asked, and I told him. Ninety-three million miles in radius and a million miles in diameter. He cracked up. "And they call you a hard science fiction writer?"
Twelve years.
I turned in the manuscript for The Ringworld Engineers in October or thereabouts, and I've been going antsy ever since. The $30 acid-free hand-sewn hardback is out now, and the more mundate hardback should have reached Lunacon about the time I did, and Publishers Weekly did a good review. Once it's in book format, the compulsion goes away, almost.
This book means a lot to me.
Ringworld came out ten years ago. Ten years ago people started asking me about a sequel. I said there wouldn't be one. Nobody believed me.
"You left it wide open for a sequel," I was told. And I explained that Louis Wu would be returning to the Ringworld, but I would not.
And I went on with my career ... testing my versatility every so often by trying things I'd never done before, nonfact articles, TV scripts, vignettes, collaborations ... but the Ringworld just kept tapping me on the shoulder.
In the halls at Noreascon, MITSFS students were chanting, "The Ringworld is unstable!" (Well, I knew there would be attitude jets. There wasn't room for everything in one book!)
During one of my speeches an audience member pointed out that the Ringworld is quite simple mathematically. Treat it as a suspension bridge with no endpoints.
Dan Alderson did some dynamic studies of the Ringworld. He pointed out that you could put several in a system, in different orbits and with different diameters. He also wrote of a solar system that contains four: at right angles to each other, the size of Earth's orbit and rotating past each other on frictionless bearings, and a fourth the size of Jupiter's orbit, for Mesklinites, rotating at a good fraction of lightspeed.
I wrote an articles on large structures.
Minneapolis fans wrote a ballad that included, "Oh the Ringworld is unstable, yes the Ringworld is unstable, yes the Ringworld is unstable! Did the best that he was able, and it's good enough for me!"
Peter Weston passed the word from a British college professor: the tensile strength of the Ringworld floor needs to be on the order of the force that holds an atomic nucleus together. From such stuff you could make a garbage bag that would hold a thermonuclear explosion.
Fans kept asking about the sequel.
Freeman Dyson wondered why anyone would build one Ringworld. Woudln't a lot of little ones be safer? I started wondering about that myself.
A high school teacher used Ringworld in class. Her students concluded that the Ringworld's worst problem is that all the topsoil would wind up in the bottoms of the oceans in about three thousand years. Definitely a problem.
I worried about Louis Wu. He'd been hit with a tasp. He knew what it felt like under the wire --
Two friends -- Ctien and Dan Alderson, both computer programmers -- finally solved the difficult problem of the Ringworld's exact instability. The Fist-of-God impact would grind the structure against its sun in three and a half years.
Jesus! I'd never dreamed it was that bad!
I started thinking about the Ringworld in earnest ... and, you know, there were things nobody had noticed. I left clues to the identity of the Ringworld engineers, but why they built it still needs some explanation. Halrloprillalar was clearly talking through her hat; she didn't know. And there had to be a lot more Ringworld races ...
I started a sequel after all.
It was as scary project. Ringworld had won a Hugo and a Nebula. I'd been learning for ten years; how could I risk showing that I hadn't become a better writer? Big structures are not a new thing any more, what with Rendezvous with Rama and Orbitsville and Titan. The Ringworld itself isn't new any more. The sequel to Ringworld had to be better than Ringworld.
Friends continued to help. Frank Gasperik suggested that with no coal or oil on the Ringworld, any civilization at our level would be using alcohol for fuel, and maybe making plastic from the residue. Dan Alderson gave me data on the Ringworld meteor defense.
And now it's done.
There will be no more Ringworld novels. I said so the last time; maybe this time you'll believe me. Have I ever lied to you before?