What if the Manhattan Project had started earlier?

[25thID]

It was six years from the time in August 1939 that Einstein alerted FDR about the possibility of building atomic bombs with uranium, to the time a uranium bomb was detonated in August 1945. But the Manhattan Project to build that bomb only started in 1942. The first three years were spent in doing sparsely-funded research and in compiling a series of study committee reports. Scientists at the time and later complained about the “swimming in syrup” pace of that early work. What if the government managers (Lyman Briggs, Vannevar Bush) had pushed that preliminary study phase a bit faster? What if the effort to actually build the bomb had then been launched sooner?

How would our having the atom bomb even four or five months sooner have affected the Allied Victory and the postwar world?

 

[Pesterfield]

Why did you decide on four or five months instead of a year or two?
How much of the 1942-1945 gap was avoidable?

Either way it'll be important to know how many bombs are produced, is it like otl just a few and used immediately or will they be stockpiled for the invasion of Europe and/or Japan?

Also will an earlier start on research mean a more effective bomb?

 

[Mark E.]

How would our having the atom bomb even four or five months sooner have affected the Allied Victory and the postwar world?

Such a bump would have been possible. FDR would still have been president, ordering two bombs on Germany. Truman takes over and assures people he will bomb no more if a surrender is tendered.

 

[25thID]

Why did you decide on four or five months instead of a year or two?
How much of the 1942-1945 gap was avoidable?

Either way it'll be important to know how many bombs are produced, is it like otl just a few and used immediately or will they be stockpiled for the invasion of Europe and/or Japan?

Also will an earlier start on research mean a more effective bomb?

Why did you decide on four or five months instead of a year or two?
How much of the 1942-1945 gap was avoidable?

Either way it'll be important to know how many bombs are produced, is it like otl just a few and used immediately or will they be stockpiled for the invasion of Europe and/or Japan?

Also will an earlier start on research mean a more effective bomb?

I was being intentionally "conservative" in saying that saving just a few months during the 1939-1942 "swimming in syrup research phase is a very plausible counterfactual. But some of the scientists, the likes of Szilard and Lawrence, did eventually write that from a technological point of view, the program to actually build the bomb could have gotten going a year or more earlier.
I am not sure that the actual Manhattan Project phase (42 to 45) could realistically have gone any much faster. As it was, they were actively pursuing the several different isotope separation methods, EM and Gas Diffusion, (along with thermal diffusion and centrifuges for awhile), plus breeding plutonium in graphite and in heavy water piles, all at the same time, i.e. building the industrial plants before piloting them or even really designing them. So kudos to Leslie Groves, I don't think we can say he could have done his job faster.

Also, it's a very challenging question of how they would be used if we had say 6 or 8 bombs available before the defeat of Germany. Indeed, would they have been used "preferentially" on Germany in keeping with the strategic objective of defeating the Nazis first, only later turning toward Hiroshima, Kokura, Nagasaki? Or would they be used essentially simultaneously on both Germany and Japan? Asked another way: how would FDR explain "holding back" a war-ending weapon from the Pacific theatre even for a few weeks, and thereby continuing to let US forces die there, just to end the war in Europe first?

As to a more effective bomb given more design time. Hmm. Gotta think about that one.

 

[25thID]

Such a bump would have been possible. FDR would still have been president, ordering two bombs on Germany. Truman takes over and assures people he will bomb no more if a surrender is tendered.

I don't disagree, but wonder if we are confident that the Japanese would have seen the glowing ruins of, say, Dresden, or Hanover and would have 1) believed they had been destroyed by atom bombs and 2) would have been prompted to surrender.

 

[naraic]

Why did you decide on four or five months instead of a year or two?
How much of the 1942-1945 gap was avoidable?

Either way it'll be important to know how many bombs are produced, is it like otl just a few and used immediately or will they be stockpiled for the invasion of Europe and/or Japan?

Also will an earlier start on research mean a more effective bomb?

Starting four or five months early would have had the Manhattan project starting at the same time as Tube Alloys.

Churchill approved Tube Alloys in August 41. Roosevelt approved the Manhattan project in January 1942. Starting 4-5 months early would be starting at the same time as the British which would seem reasonable.

In early 1942 a number of British scientists from Tube Alloys visited America and shared information with the Manhattan project. I would imagine that if the Manhattan project started earlier there would be less benefit from the British visit. So starting 5 months early might mean a boost of 2-3 months in the final project.

 

[marathag]

As to a more effective bomb given more design time. Hmm. Gotta think about that one.

Teller was thinking about his 'Super' during the War, after all.
But many of the post war developments can up during the War, but put off in the race to get bombs ASAP.
So you could see using composite Uranium/Plutonium cores for implosion devices(Oak Ridge could make more HEU than Hanford could do Plutonium), more lenses and of better geometry and HE composition for better efficiency, and levitated pit.
All that together means an early Mk 5 bomb with a 120kt yield for same size and weight, with Tritium boosting around the corner for even higher yields. just going to 60 lenses from 32 will get you 50-60kt

 

[Garrison]

The early research was relatively slow because Uranium fission had only been discovered in 1938 and no one knew if this was something that could actually be weaponized. During 1939-42 it wasn't really a weapons program, it was basic scientific research exploring the physics of nuclear fission.

 

[25thID]

Teller was thinking about his 'Super' during the War, after all.
But many of the post war developments can up during the War, but put off in the race to get bombs ASAP.
So you could see using composite Uranium/Plutonium cores for implosion devices(Oak Ridge could make more HEU than Hanford could do Plutonium), more lenses and of better geometry and HE composition for better efficiency, and levitated pit.
All that together means an early Mk 5 bomb with a 120kt yield for same size and weight, with Tritium boosting around the corner for even higher yields. just going to 60 lenses from 32 will get you 50-60kt

You are surely right: a more potent fission bomb as you suggest could have been developed sooner if the project had started earlier. But whether the US had gotten serious about building the bomb a year, or a few months earlier, wouldn't there have been the same urgency to get something that would work built sooner rather than get a better one later? Yes, someone like Kistiakowsky might have said, "This design has a good chance of working, but I can get you more 'effective' implosion if you give me another few months", but would Groves (under constant schedule pressure from Marshal) have let him and the rest of Oppie's team have more time? So I am not sure an earlier start would have produced an even more powerful bomb to end the war, but rather, a bomb akin to the actual ones, produced and used earlier. I think.

 

[25thID]

Starting four or five months early would have had the Manhattan project starting at the same time as Tube Alloys.

Churchill approved Tube Alloys in August 41. Roosevelt approved the Manhattan project in January 1942. Starting 4-5 months early would be starting at the same time as the British which would seem reasonable.

In early 1942 a number of British scientists from Tube Alloys visited America and shared information with the Manhattan project. I would imagine that if the Manhattan project started earlier there would be less benefit from the British visit. So starting 5 months early might mean a boost of 2-3 months in the final project.

I agree about Tube Alloys vis a vis Manhattan; but before Tube Alloys came the Brits' Maud Committee, akin to our Uranium Committe under Lyman Briggs, and there were personnel from UK (e.g. Tizard and Cockcroft) who came to the US personally and shared Uranium info in late 1940. The Brits also in that timeframe shared the "breakthrough" report co-authored by one of the "discoverers" of fission (Fritsch). That report showed that a uranium bomb was indeed feasible as to mass of U required, as to practicality of U isotope separation, as to cost and as to time required. Had Briggs not promptly locked up that mid-1940 report from the Brits in his safe, to be shared with no one, the US researchers still trying to answer those questions throughout 1940 and 41s could have made a quantum leap forward.
Point is that the US program on its own could have moved faster but for comparatively lethargic human management. In addition, the US program could also have gotten accelerated if the managers had paid attention to the data the Brits were sending them, and which the Brits' Cockcroft spent weeks crisscrossing the US to get the Comptons and the Lawrences energized about.
But now, looking at it from another angle, say that the US had made progress sooner even without paying attention to the Brits' input. So when the US started the bomb building in earnest, they would have been even less inclined to merge their effort with Tube Alloys and invite the Brits to participate. As it was, Groves truly was relatively unreceptive to the couple dozen Brits who helped out at Los Alamos and elsewhere. So a more nearly total exclusion of Brits from the effort is plausible.
In which case, Klaus Fuchs would never have set foot inside Los Alamos.

 

[25thID]

The early research was relatively slow because Uranium fission had only been discovered in 1938 and no one knew if this was something that could actually be weaponized. During 1939-42 it wasn't really a weapons program, it was basic scientific research exploring the physics of nuclear fission.

Yes and no.
It is true that no one knew if a bomb could actually be built, in a timeframe before the war was otherwise ended. So, a period of research into the physics of fission was of course necessary before anyone could bend metal. Moreover, there were folks in the US scientific community who initially only thought nuclear fission might someday be used as a propulsive power source for ships, not a way to vaporize fleets of them.
However, the reason FDR set up the Uranium Committee was because Einstein's August 1939 letter had specifically raised the spectre of a city-destroying bomb, and warned that the Nazis could already be working on it.
But regardless of whether we characterize that early work as basic research or as much more mission-focussed development, the contemporary evidence indicates that it could feasibly have been conducted with more budget, more resources, more coordination (such as with the Brits who were far ahead). Just one example: Fermi requested $6,000 to help him build his first experimental pile at Columbia University ( not the famous one in Chicago). It took the government apparently more than 6 months to get it into Fermi's hands. That inertia was not due to any nuclear fission physics phenomena. It was due to bureaucratic boot dragging. But for early management actions such as this, I believe the bomb effort could have yielded results sooner.

 

[Pesterfield]

but would Groves (under constant schedule pressure from Marshal) have let him and the rest of Oppie's team have more time?

They were already working on two bomb designs, what's a few more?

 

[25thID]

It would have been a question of time.
Marathag said that if the team had started developing the bomb earlier, they might have been able to come up with a more potent weapon, by August 1945, i.e. if they had been given the time by the Pentagon to continue refining the bomb design. Yes, quite possibly a "better" bomb could have been developed by August 1945. But my point is that an earlier start to the bomb project would have encountered the same, but earlier, pressure from the Pentagon to use a workable one as soon as possible. Would the Pentagon have allowed the Los Alamos team to go ahead and take more time and develop more designs so they could later use the most efficient one? I don't think so. An earlier start on the bomb effort would not have led to a longer bomb effort still ending in August 45. It would have led to a bomb-building effort of about the same duration, culminating earlier, perhaps destroying Dresden atomically instead of incendiarily.

 

[marathag]

. Would the Pentagon have allowed the Los Alamos team to go ahead and take more time and develop more designs so they could later use the most efficient one?

The Gun type might never been used, as it used several Critical Masses worth of Uranium to make 12kt.
If things are advanced enough on the implosion design, then Gadget may have used Uranium for the implosion test, then a 2nd test with Plutonium.
At that point in the ATL, the Mk1 Little Boy might remain a paper design, like the Mk2 Plutonium Gun, Thin Man.
HEU and Plutonium would be used for implosion
The Mk 3 Fatman would get maybe a half dozen cores manufactured before improved designs would be manufactured, like in air loading Capsule loading like the OTL Mk 4

 

[Issei Uzumaki]

It was six years from the time in August 1939 that Einstein alerted FDR about the possibility of building atomic bombs with uranium, to the time a uranium bomb was detonated in August 1945. But the Manhattan Project to build that bomb only started in 1942. The first three years were spent in doing sparsely-funded research and in compiling a series of study committee reports. Scientists at the time and later complained about the “swimming in syrup” pace of that early work. What if the government managers (Lyman Briggs, Vannevar Bush) had pushed that preliminary study phase a bit faster? What if the effort to actually build the bomb had then been launched sooner?

How would our having the atom bomb even four or five months sooner have affected the Allied Victory and the postwar world?

While technically the project was greenlit in 1942, the origins of it are actually in fall of 1939 with the first studies to determine if it was feasible, so all you really need is FDR to be convinced by the Advisory Committee on Uranium in the fall of 1939 that not only is it possible but they should begin researching potential bomb applications ASAP. You could therefore have a theoretical startup by Spring of 1940. So if you go along the OTL development TL, you then get a bomb by late '43, or early '44 at latest, as long as you also get the same type of funding.

EDIT: Forgot to actually answer your question on impact, oops.

My take, is that if it is done before D-Day, they probably just build a stockpile up until they can get back into France, otherwise without air superiority they could not ensure a bomber could get through to drop it. That being said, as soon as they think they have a safe enough window to get to Berlin, that bad boy gets dropped. They didn't target Tokyo because the Emperor was deemed necessary to ensure the peace and didn't want to kill him in the blast but thats not an issue in Germany. Once that bomb is dropped, you get a push for peace from remaining soldiers and all efforts, you have a far different cold war borders, assuming it still comes to that.

The interesting domino to fall would be Japan. The USSR did not agree to attack Japan until Yalta in 1945. If you knock Germany out a year early, you now have the entire weight of US/UK/French forces coming down on Japan. I could actually see the Allies telling Stalin his help isnt needed, not wanting communist influence to spread. Imagine the US / UK fleets now so throughly destroying Japan by mid-1944 that the Philippines are taken that much sooner with all the US war effort on that. you probably get an invasion of Formosa in this new TL as well to truly cut off Japan from DEI. Then once the US is close enough to US B 29s, the stockpile of A-bombs starts dropping on any and all military targets they could find. That might get a Japanese surrender by spring of 1945.

 

[Horton229]

I am not sure you necessarily get to a Mk5 or Mk6 early enough to be war ending weapon. The focus will still be on a workable design.
With the extended time, you might have more fissionable material. Once the implosion device is shown to work, you can use HEU in such devices as they are more efficient, so there are possible more bombs.
One issue is delivery. Can the B-29 program be spend up as well?

 

[marathag]

One issue is delivery. Can the B-29 program be spend up as well?

Not really,as much of that was over the Wright engine fiasco, that took Dodge, yes the car company, to sort out many of the issues that Wright missed.
But even with the crap early Wrights, the B-32 had less problems with engine fires than the B-29, better nacelle design for cooling.
My idea is that rather than the B-32 as lower priority 'backup' to Boeing, it's equal, so has an extra billion dollars spent on it, to work out the bugs in pressurization turret fire control and other bits.

 

[Horton229]

I figured the B-29 was 'done' just about as fast as possible, so an alternate delivery vehicle, given an 'expectation' of a working bomb in, say, late-1944 makes a lot of sense. Given the sums of money spent, another billion here or there isn't likely to break the bank.

 

[CaptainCalvert]

They were already working on two bomb designs, what's a few more?

The German nuclear programme suggests that you can have too much of a good thing!

More seriously, there are only so many top scientists and engineers to go round. Until you have a working device, the best should be trying to make a working bomb plus maybe a Plan B (as OTL).
That means your bomb improvement team will of necessity be slightly less top flight, and will come second for lab space, tests etc. They may well be able to do good preparatory work, but real improved performance will have to wait until there's an acceptable process for making working bombs so the A team can shift priorities.

 

[Bernard Woolley]

Skipping over the technical discussion, an earlier available bomb is going to be bad for Germany. If the B-29 isn’t available, the Lancaster would be a viable delivery platform, having been studied for the job. Depending on when the first weapons are available, there may be no D-Day.

What’s interesting to think about is whether the Allies use the bombs as they become available, as they essentially did with Japan, or build up a stockpile to hit Germany with several almost simultaneously.