Arthur Kantrowitz? Gerard K. O’Neill? Timothy Leary? Arthur C. Clarke? Anonymous?

Question for Quote Investigator: Grand futuristic projects such as the following four examples have been greeted with a mixture of hope, excitement, skepticism, and derision:
(1) Laser propulsion systems for spacecraft
(2) Space-based solar power systems
(3) Space habitats with thousands or millions of people
(4) Space elevators on the Earth or the moon
A proponent was asked to give a timeline for the development of one of these advanced technological systems. The reply was ingenious:
You’ll have the result ten years after you’ve stopped laughing.
This statement has been attributed to U.S. physicist Arthur Kantrowitz, U.S. physicist Gerard K. O’Neill, U.S. psychologist Timothy Leary, and English science fiction author Arthur C. Clarke. Would you please explore this topic?
Reply from Quote Investigator: The earliest match found by QI appeared in “The CoEvolution Quarterly” in September 1975. The clever response was attributed to Arthur Kantrowitz by Gerard K. O’Neill.
Kantrowitz was the longtime director of the Avco-Everett Research Laboratory. He and his colleagues made advances in multiple technologies, e.g., supersonic wind tunnel design, magnetohydrodynamic power generation, superconducting magnets, and laser propulsion.1
O’Neill was a Professor of Physics at Princeton University who pioneered particle storage rings for high-energy physics. He also designed space habitats and advocated for space manufacturing. In 1975 O’Neill was interviewed by editor and entrepreneur Stewart Brand who asked him about the timeline for developing a space habitat housing thousands of people. O’Neill presented the words of Kantrowitz. Boldface added to excerpts by QI:2
Arthur Kantrowitz, the president of AFCO-Everett was out visiting us a few days ago. He happens to be quite enthusiastic about this work, and he says that his answer for things of that kind is to say, “You’ll have the result ten years after you’ve stopped laughing,” which is I think, a pretty good answer.
The most responsible answer I could give is to say that if I really had the responsibility for getting it done by a certain time and the authority to do it in what I would consider the right way, then I would be willing to make a very strong commitment that it could be done in 15 years from time-zero. Whatever that time-zero is.
QI believes this saying should be credited to Arthur Kantrowitz although the evidence is indirect. QI has not yet found a citation containing the quotation directly from Kantrowitz.
Below are additional selected citations in chronological order.
Continue reading “Dialogue Origin: “When Will This Futuristic System Be Built?” “Ten Years After You’ve Stopped Laughing””