“Permission to believe” in a Moore’s Law for space launch? (part 1)
Both chips and rocket launchers are fabricated from increasingly advanced materials, but in making rockets, there is no obvious analog to “making things smaller.” For example, to increase specific impulse is to make things worse, in a way: a rocket is almost a bomb, and increases in specific impulse tend to make rockets more bomblike. SpaceDev supplied SpaceShipOne with an admirably safe, simple hybrid rocket engine, but hybrids that depend on pressurized gas oxidizer will have pressure vessels with thick walls, and the fuel is contained in cylinder that has to be quite long. Both of these design issues increase the weight of an engine that has inherently lower specific impulse than most liquid-fuel or solid-fuel engines. Scaled Composites’ contribution was primarily aeronautical: how to increase the initial launch altitude and reduce the weight of a space plane. But altitude is a relatively small contributor to the cost of getting to orbit, and are space planes the future for reaching orbit?
Nor is there an obvious analog to increasing chip dimensions, which is possible mainly because of increasing purity in making silicon wafers. It’s nice to have lighter composite materials to make rockets out of, naturally, but the amount that you can lift ultimately has to be governed by the rocket equation, in which fuel weight is the main governing variable. That takes you back to specific impulse: how to pack a punch without knocking yourself out.
An analogy for “circuit cleverness” in launch systems isn’t easy to draw. The basic design of rockets hasn’t changed in decades. We seem to be down to the second- and third-order optimizations. Some have pointed out that SpaceX’s design involves little more than a commercial implementation ideas of Truax and von Braun.
Furthermore, an orbital-class launcher is far from being free from detailed consideration of trade-offs. Someone once characterized an airliner as “a bunch of compromises flying in close formation.” A rocket launcher might be thought of as a bunch of sharks swimming so closely together and so rapidly as to be in constant danger of inflicting bleeding wounds on each other. Just one little fin-nick, and the water boils red.
Finally, Moore made no mention of the magic of photolithography. Perhaps that went without saying for his audience. Fabrication of circuit features on chips is by far the most parallel factory automation process ever. Exposure of layers through mask patterns creates millions of on-chip artifacts simultaneously. It’s only in recent years that barriers to optical scaling have appeared, as feature dimensions drop below the wavelengths of light. Hopes for some similar parallelism in building launch systems, which are so much more three-dimensional than silicon chips, may only be in nanotechnology: a still-uncertain prospect, at least for manufacturing large objects like launchers.
Permission and marketing
Not only is physics on your side in IC fabrication, so is market demand. Moore continued: “…especially the cost of doing things electronically drops as a result of the technology.” That is, given that there is demand for information processing capacity, there is a true driver: people want to do things electronically. Feynman’s “room at the bottom” will be increasingly colonized under the pressure of market forces.
Compare that to the space industry. There are increasing terrestrial and atmospheric substitutes for orbit, some of them courtesy of the same technologies that gave us SpaceShipOne, others (like the transoceanic optical fiber surplus) an unintended consequence of Moore’s Law. The space hotel concept remains intriguing but unproven: no sane billionaire is likely to slap down the cash it would take to test that market. Far from risking their jobs by not coming up with innovations on the clocktick of some space-launch Moore’s Law, launch visionaries, time and again, in their attempts to pioneer some advanced launch concept, have only been handed a ticket to career oblivion.
Paranoia as a virtue
VLSI pioneer Carver Mead spoke of a “permission to believe” that the electronics industry had gotten from Moore’s Law. Moore’s Law seems, by contrast, to have benefited almost immediately from a requirement to believe. As Moore wrote in a retrospective 1995 essay contributed to Engines of Innovation: U.S. Industrial Research at the End of an Era,
…once something like this gets established, it becomes more or less a self-fulfilling prophecy. The Semiconductor Industry Association puts out a technology road map, which continues this generation [turnover] every three years. Everyone in the industry recognizes that if you don’t stay on essentially that curve they will fall behind. So it sort of drives itself.
“Sort of drives itself,” sounds gentle, like some futuristically autonomous luxury automobile. Andrew Odlyzko put it in more savagely Darwinian terms, in his paper, “The Decline of Unfettered Research”:
Management is not telling a researcher, “You are the best we could find, here are the tools, please go off and find something that will let us leapfrog the competition.” Instead, the attitude is, “Either you and your 999 colleagues double the performance of our microprocessors in the next 18 months, to keep up with the competition, or you are fired.”
Space launch could use to be so red in tooth and claw. Or should it be?
Moore’s Second Law: show me the money
The outlook for capitalizing a private launch industry may be dimmed by a crisis that the IC industry, after a long run, could now be headed for itself: a twilight in the financial markets.
In his paper about photolithography and the future, Moore cautioned:
I am increasingly of the opinion that the rate of technological progress is going to be controlled from financial realities. We just will not be able to go as fast as we would like because we cannot afford it, in spite of your best technical contributions. When you are looking at new technology, please look at how to make that technology affordable as well as functional.
In this, Moore is invoking what has come to be called Moore’s Second Law: IC fab lines aimed at the next doubling in transistor capacity tend to cost exponentially more than the current generation of fab lines.
Live by the market imperative, die by the market imperative. In the above Engines of Innovation essay, Moore “describes why Intel of all companies chose not to create a corporate research unit”, according to one review. Note that this is in a book that bemoans the eclipse of the big corporate research labs, an underappreciated source of fundamental innovation. It seems that Intel was on the leading edge socially, not just technically.
Relentless downsizing and a focus on short-term profit is not the R&D environment that encouraged researchers to invent the transistor and photolithography, the two enabling technologies for Moore’s Law. As the Baby Boom ages, and corporations must increasingly demonstrate earnings in the wake of the Bubble to justify their inclusion in boomer stock portfolios, further investment in more advanced IC fabrication for ever-greater computer power (and we might reasonably ask, for what?) may yet fall prey to Moore’s Second Law. The very long-term R&D investment required for expensive orbital vacation complexes may never even start.