While I’m on the subject of foundational concepts in the relationship between science and engineering, here’s the outline of a methodology for applying current science to assess lower bounds on the capabilities of a select subset of future technologies. (As many of you know, some of those lower bounds are startlingly high.)
A subset of the potential capabilities of future levels of technology can be understood by means of a design process that can be described as exploratory engineering. This process resembles the first phase of standard design engineering (termed conceptual engineering, or conceptual design), but it serves a different purpose:
- In standard engineering, design leads to the manufacturing of a product.
- In exploratory engineering, design leads to understanding of what a future manufacturing process could produce.
Because of this difference in objective (products vs. knowledge) conceptual engineering and exploratory engineering have both similarities and differences:
|
|
Conceptual engineering |
Exploratory engineering |
|
Objective |
Create and evaluate system-level designs (typically parameterized) |
— Same — |
|
Background technology |
Known capabilities delivered by current fabrication technologies |
Conservative, physics-based estimates of capabilities delivered by future fabrication technologies |
|
Process of analysis |
Identify required subsystems and components, and their required performance parameters |
— Same — |
|
Basis of calculations |
Typical performance of available materials and components |
Conservative, physics-based estimates of lower bounds on the performance of feasible materials and components. |
|
Results of calculations |
Estimates of the performance of fully refined, system-level designs |
Lower-bound estimates of the performance of fully refined, system-level designs |
|
Production and performance |
Product must be manufacturable and competitive today |
Product is not manufacturable today, and need not be competitive in the future |
|
Implication for design criteria |
Seek efficient configurations to maximize performance and minimize cost of production |
Seek simple designs and assume large design margins to maximize confidence and minimize cost of design analysis |
|
Results of the design process |
Choice of system-level design concepts for refinement and possible production |
Estimates of the capabilities of future levels of fabrication technology for evaluation of research and policy options |
In the early 20th century, a missing fabrication technology was the combination of engineering expertise and metalworking techniques (among others) that were required to build large aerospace vehicles. The physics of rocket propulsion, however, were well understood, and the strength and weight of large, well-made aluminum structures could be estimated with reasonable accuracy.
On the basis of exploratory engineering applied to this kind of knowledge, engineers who studied the matter were confident that orbital flight could be achieved by means of multistage chemically fueled rockets. By the 1940s, a study by the British Interplanetary Society had filled in considerable detail and given a good estimate of the size of a vehicle that could reach the Moon.
Those who hadn’t studied the matter were sometimes confident of the opposite.
Astronomers who knew the daunting speed of orbiting objects (but didn’t trouble to examine the exploratory engineering analysis) sometimes called spaceflight absurd. In a characteristic move, a Professor of Physics and Chemistry, one A. W. Bickerton, demonstrated the impossibility of something irrelevant, then generalized it: He did a silly calculation that implicitly assumed that a rocket must put its fuel into orbit (and a bad fuel, at that), then announced that spaceflight was simply impossible.
Reasoning from the unworkability of a bad idea to the impossibility of a well-researched engineering concept is a repeated theme of interactions at the interface between science and engineering. (Engineers ignoring a crucial scientific fact is, of course, another.)
Here’s an entertaining list of quotations from the history and prehistory of flight, and spaceflight.
See also:
- How to Learn About Everything
- How to Understand Everything (and Why)
- A Map of Science
- The Antiparallel Structures of Science and Engineering
- Science and Engineering: A Layer-Cake of Inquiry and Design
- A Telescope Aimed at the Future
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Jeffrey Soreff 08.29.09 at 5:33 pm UTC
Would you consider “Heteroaromatic Rings of the Future” (William R. Pitt*, David M. Parry†, Benjamin G. Perry‡ and Colin R. Groom, J. Med. Chem., 2009, 52 (9), pp 2952–2963
DOI: 10.1021/jm801513z) to be exploratory engineering? They aren’t specifying the fabrication technology in detail, but do select a large subset of the skeletons as synthetically tractable. In the application to medicinal chemistry, simply increasing the number of viable alternatives is a help, so in
that sense they are improving a lower bound on performance.
Eric Drexler 10.31.09 at 8:35 pm UTC
Yes, of a sort — but a rather unusual sort.