Eh, it varies. The apollo program was pretty good. There was some stuff with networking that seemed to take off a few years ago. The human genome project was pretty spiffy.
On the other hand, the Manhattan Project beats all of these aside from that obscure networking stuff, Apollo and the HGP were more taking existing working stuff and doing it on a more ambitious scale. I've been studying the Manhattan Project as of late, and it's for example amazing how much the plutonium path was pushed before they understood really important details about it, like fast neutron cross section, average number of neutrons from fast neutron fission (needs to be > 1), how to chemically isolate it after transmutation in a natural uranium reactor, and how to do that with that fantastically radioactive irradiated stuff.
Or the faith that they'd be able to develop a good enough membrane for the Oak Ridge gaseous diffusion plant (high pressure + fiercely corrosive UF6). Or how they got all this in motion before having good bomb designs, and how the Pu240 contamination of reactor brewed vs. cyclotron created plutonium required getting the most difficult bomb design to work ... and it worked the first time! Or how they set to making multiple reactors before they really knew they'd work, and if the size they'd chosen would work in the face of the neutron poisons it would likely generate.
And in such short time; study of the people and their methods of management (e.g. Groves and Oppenheimer) is very worthwhile for many HN readers.
The interesting part about the Manhattan Project wasn't the funding of the R&D. It was the fact that we created an entire industrial infrastructure to pull it off.
Almost 84% of the Manhattan Project funding went to the industrial production at Oak Ridge and Hanford--more than 80% of all funding went just to producing fissionable material.
Almost 1 in every 250 Americans worked on the Manhattan Project.
This wasn't just big. It was unprecedented. And it almost didn't work. If the atomic bomb had been delayed even a few more months, the war would have been over.
If the atomic bomb had been delayed even a few more months, the war would have been over.
Very possibly not; Operation Olympic, the invasion of the smaller main island of Kyushu, was in every mind but McCarther's on hold due to massive reinforcements and an (underestimated) huge number of kamikazes available. Those who knew about the bomb were planning on using a number of them for that invasion if the initial 2-3 demonstrations of it failed, those who didn't were planning on using chemical weapons (I think in general, but maybe for or also for Olympic). So what would have happened if the war dragged on to it's scheduled October 1945 date? We can't know.
But the rest that you say, yeah. Bohr didn't think the project was feasible without turning a nation into a factory, and upon coming here, noted that was indeed what we did.
I would start with Rhodes' The Making of the Atomic Bomb (http://www.amazon.com/The-Making-Atomic-Bomb-Anniversary/dp/...). It has something for everyone, although many want to e.g. skip the initial 300 or so pages on the relevant developments in nuclear physics. And the author will sometimes go on excessively long digressions, like all about Swedish village where Lise Meitner and her nephew Otto Hahn did their Christmas vacation when she was the first to get the news from her colleague back in (Nazi) Germany that uranium fissioned.
Next book for the management of the project, although there's a lot more, e.g. Groves was responsible for US intelligence actions WRT to Germany and Japan's nuclear projects, one of the last chapters it titled something like "Destruction of the Japanese Cyclotron", is his Now It Can Be Told: The Story Of The Manhattan Project (http://www.amazon.com/Now-It-Can-Told-Manhattan/dp/030680189...).
Earlier publication date, so less could "be told", but lots of good stuff. E.g. when he first got an estimate of something major from the Chicago "Metallurgical Lab", he asked for the uncertainty factor, expecting something like 25%, and got a factor of 10. After explaining that in a neat "to feed somewhere between 10 and 1,000 people" metaphor, he then relates how they discussed it for a while, he realized there would be no firmer figure for some time, and then they all forged ahead. A truly remarkable man.
There's also a lot that's been published on Oppenheimer, but I'm not studying Los Alamos too much now, and e.g. the above book is very interesting for lots more details in how Groves picked him, and reexamined it in late 1944 or so because of Oppenheimer's relatively poor health and still couldn't find a replacement (as noted by Rhodes, if Oppenheimer had lived just a bit longer he ought to have gotten a Nobel for his earlier and way ahead of it's times late '30s theoretical astronomy on topics like neutron stars and black holes).
I'm in the middle of the Manhattan Project section in this much more specialized book, which has a political science analysis focus that's not going to be of interest to most of us, but it's quite promising, the railway story is neat and feeds right into Germany's physics establishment story; check back with me in a few weeks to see if it's worth your while: Technology and International Transformation: The Railroad, the Atom Bomb, and the Politics of Technological Change (http://www.amazon.com/gp/product/0791468682) the cheapest copy is now $19 (plus shipping), vs. the $3 I got it for, so it's very possibly not worth it.
I've also got these books on order: The General and the Bomb: A Biography of General Leslie R. Groves, Director of the Manhattan Project (http://www.amazon.com/gp/product/0396087612) and suggested from the previous book The Atomic Scientists: A Biographical History (http://www.amazon.com/gp/product/0471504556) which might be interesting if you really like the first 300 pages of Rhodes' book.
The key is to keep the project small. Once projects reach a certain size there's a whole ecosystem of bureaucratic parasites that latch on and begin feeding. "Purple suit" projects like this one are particularly prone to this problem since they involve three or four giant bureaucracies from the get-go.
As an alternate path, forget limiting project size, find harmless places to store the bureaucrats, and decide that success is worth whatever amount of money it takes.
I think that last element helps explain the Manhattan Project's success, rightly brought up by a poster above. They simply had to succeed and they were potentially able to tap the wealth of the entire United States to make it happen. Smart, motivated people + quasi-infinite resources: things can happen.
