What if the Manhattan Project had started earlier?

[marathag]

OAK RIDGE (Total) $1,188,352,000 63%
—K-25 Gaseous Diffusion Plant $512,166,000 27%
—Y-12 Electromagnetic Plant $477,631,000 25%
—Clinton Engineer Works, HQ and central utilities $155,951,000 8%
—Clinton Laboratories $26,932,000 1%
—S-50 Thermal Diffusion Plant $15,672,000 1%
HANFORD ENGINEER WORKS $390,124,000 21%
SPECIAL OPERATING MATERIALS $103,369,000 5%
LOS ALAMOS PROJECT $74,055,000 4%
RESEARCH AND DEVELOPMENT $69,681,000 4%
GOVERNMENT OVERHEAD $37,255,000 2%
HEAVY WATER PLANTS $26,768,000 1%

You can see, that R&D was one of the cheaper aspects of the Program, Big Money went to the engineering side

Lancaster would be a viable delivery platform

Too low a ceiling, and just too slow. You have 44 seconds from 34,000 feet to be clear of the detonation area. B-29 Silverplates got 9 mile slant range away from Ground Zero, and that caused sever buffeting

 

[25thID]

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

Well yes, if the bomb project had started earlier, then more refined designs might have been available by August 45, but what I was trying to say, perhaps inelegantly, is that if the bomb project had started earlier, the pressure from the Pentagon and White House would have started earlier too, so the Los Alamos crew would not have been given the time to work on the several refined designs as you mention before the first ones were used. As you probably know, the Thin Man Plutonium Gun got somewhat further along than a paper design---a batch of 17 foot long gun barrels was cast for that planned weapon before it was discovered that the isotopic mix of the reactor-bred Pu, as compared to the early, cyclotron-created Pu made it so readily and rapidly fissionable that a gun detonation was not feasible. The attached authentic photo of the planned Thin Man gun barrels is from the counterfactual history: Mangi, J. The First Atomic Bomb 2022 Pen & Sword.

 

[25thID]

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.

I agree with you that had FDR and the Uranium Committee acted differently as you suggest, it is conceivable to get an A-bomb much much earlier (not just the few months that I postulated), and indeed that would set US/UK on a different path to victory both in Europe and Pacific, with, as you say, very different postwar developments in both theatres.
I believe the soviets expressed their intent as early as the Teheran conference of 1943 to invade Japan after the defeat of Hitler, but I agree with your point that the proven existence of atomic bombs would have changed the US attitude toward soviet involvement. But in reality, the US was of somewhat mixed mind about that all the way through to the end--we didn't need Bolshevik boots on the ground, but dead Soviet Soldiers were preferable to similar numbers of dead US and UK ones. Besides, Soviet plans were not so much in response to any "request" or need for help on our part, as it was an opportunity for Stalin to redress the 1905 defeat of Russia by Japan. That is, Stalin was going to go into Japan soon after the Nazi defeat whether we welcomed him doing so or not.

 

[25thID]

Given workable bombs (not necessarily the most efficient designs) being available (and deliverable) somewhat earlier, say late 44 or 45 as the consensus seems to be a plausible situation, then the strategic plan does open up. Use however many as it takes on Germany to get surrender, then turn to Japan and use more as needed? Or use them, like any other weapon, in both theatres concurrently? I agree, Tokyo would not be bombed, for same reason it wasn't actually---don't kill the Emperor God. But I don't think we'd bomb Berlin either, because by late in the war, we knew Hitler was a subterranean madman. How would it be if we had nuked Berlin only to have Hitler crawl up out of his deep bunker a day or two later like an invincible god? However, using atom bombs (instead of HE and napalm) to destroy the likes of Dresden and Hanover, and Yokohama and Kobe more or less at the same time, might have helped convince both capitals that "there's plenty more where they came from". That is, just as we truly did make a quasi-bluff ( we really only had only one more bomb ready to go in August 45) and one or two a month after that, if we had the bombs earlier and still had two wars going, we would have built up a bare minimum of a stockpile before using them in both Europe and Japan and implying rapid continued production. These ideas are in Mangi, J. Dropping the Atomic Bomb on Hirohito and Hitler 2022 Pen & Sword.

 

[Pesterfield]

How would it be if we had nuked Berlin only to have Hitler crawl up out of his deep bunker

If the Allies know of Berlin bunkers would the city be hit with a ground burst and maybe multiple bombs?

 

[Carl Schwamberger]

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.

The US Navy was approved to start a atomic power project in 1939 & the budget (1938 Budget bill) reworked to fund research in 1940. This seems to have initially at least a power plant project. When the Manhattan project was authorized in 1943 the Navy research & its laboratories at the Philadelphia Navy Yard were taken into the Manhattan Project.

Heres a equally interesting point. France also initiated a large scale atomic power research project in 1939. In that year they collected all the refugee physicists they could and set them up under the coordination of the Curie Institute along with the established French researchers. France also contracted every drop of Heavy Water Norsk Hydro could produce. The last shipment of that sent in march 1940. The Belgian controlled Uranium mine in the Congo had been selling small batches for research labs and industry, but in 1939 France also contracted for every gram available & the Belgians accelerated extraction. The Germans got their hands on some 1,300 tons of Uranium ore among the other loot from France and Belgium.

I've run across a couple descriptions of a Brit intelligence officer, a Brigadier, racing around unoccupied France in the last days before the armistice. Collecting the refugee physicists & packing the off to Britain. Rhodes in 'The Making of the Atomic Bomb' identifies those who made it to the UK. Heres the trick. They were judged security risks and most kept on ice until after the Tube Alloy project started.

What France might have been able to accomplish alone or with Brit & US assistance is difficult to say, but like the US they were a step ahead in making a start in 1939 at a larger scale and coordinated research project. The key I think is getting to a actual chain reaction outside the sub micro scale on lab benches. Fermis Uranium pile in sustained chain reaction not only proved which theories & speculative paths were correct, but gave up data that accelerated development. Had France survived the 1940 campaign & got their Yellowcake & Heavy Water into a sustained reaction like Fermi, but in 1941 vs 1942 we can postulate a full years advance to a bomb.

 

[Carl Schwamberger]

Given workable bombs (not necessarily the most efficient designs) being available (and deliverable) somewhat earlier, say late 44 or 45 as the consensus seems to be a plausible situation, then the strategic plan does open up. Use however many as it takes on Germany to get surrender, then turn to Japan and use more as needed? Or use them, like any other weapon, in both theatres concurrently? I agree, Tokyo would not be bombed, for same reason it wasn't actually---don't kill the Emperor God. But I don't think we'd bomb Berlin either, because by late in the war, we knew Hitler was a subterranean madman. How would it be if we had nuked Berlin only to have Hitler crawl up out of his deep bunker a day or two later like an invincible god? However, using atom bombs (instead of HE and napalm) to destroy the likes of Dresden and Hanover, and Yokohama and Kobe more or less at the same time, might have helped convince both capitals that "there's plenty more where they came from". That is, just as we truly did make a quasi-bluff ( we really only had only one more bomb ready to go in August 45) and one or two a month after that, if we had the bombs earlier and still had two wars going, we would have built up a bare minimum of a stockpile before using them in both Europe and Japan and implying rapid continued production. These ideas are in Mangi, J. Dropping the Atomic Bomb on Hirohito and Hitler 2022 Pen & Sword.

Precisely how many bombs could be available is not easy to estimate. When Gen Groves reported on the start of the Plutonium manufacture he stated the goal was for 36 bombs in 1946. i'm unsure if that meant by the end of the year, or mid year after 12 months production. As it was the Hanford reactors were able to deliver bomb grade Plutonium for aprox four to five bombs by September 1945. In that month the reactors were shut down to correct construction defects, and make design improvements. Rhodes estimated five cores could have been ready to detonate by November 1945 & 18 more in 1946. But, that is just a best guess. The variable being how much down time the two production reactors at the Hanford site would require.

It is also possible to make a decision earlier to continue production of bomb grade Uranium for a few more gun type bombs if the need is foreseen that far ahead.

 

[25thID]

If the Allies know of Berlin bunkers would the city be hit with a ground burst and maybe multiple bombs?

I don't know if we had enough information about the bunker and about the ability of one or more ground bursts to destroy it.

 

[Bernard Woolley]

Too low a ceiling, and just too slow. You have 44 seconds from 34,000 feet to be clear of the detonation area. B-29 Silverplates got 9 mile slant range away from Ground Zero, and that caused sever buffeting

It was studied as a potential alternative. There is even some evidence that a small unit trained for the task. Lancasters could have been used in a sacrificial role if there was enough urgency to the situation.

 

[raharris1973]

The trend in this discussion towards assuming Germany is the first atomic target, or at most, debating whether the bomb is used simultaneously on Germany and Japan is ignoring one or two earlier detailed discussions on this subject. I summon thee @CalBear. There was extensive discussion about how Japan was easier to target with the weapon because of its weaker air defenses and habit of not challenging single aircraft that the Germans never conceded. I believe one of these discussions also noted that one of the earliest contemplated targets, rather than a Japanese or German city, was a Japanese fleet concentration or fleet facility at Truk lagoon in the west-central Pacific.

The factor in favor of emphasizing use against Germany early and often is the relatively more serious threat that the Germans could successfully develop their own atomic during the war than the Japanese could. (even though the threat isn't that serious). However, the argument for simultaneous use, or starting with Japan is that the small-ish number of atomic bombs available early is more likely to be a decisive killing blow against Japan than Germany, with less chance of the bomb delivery mission being intercepted or forced to abort or the bomb being captured.

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?

Great question. See my speculations above. I would vote for at least simultaneous. Not for the domestic political reasons you suggest, but for practical strategic reasons of efficacy. If the the difference in starting use of the bomb between theaters is just a matter of a few weeks, I honestly can see FDR managing the politics of that fine, justifying that on a military urgency/expertise case.

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

Not really, as you later suggest, the pressure will be there to deliver results just as soon as possible.

, wouldn't there have been the same urgency to get something that would work built sooner rather than get a better one later?

exactly, because...

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?

....bingo

So a more nearly total exclusion of Brits from the effort is plausible.

interesting....would this come with a cost in efficiency or timeliness that delays completion of a usable weapon (maybe not compared to OTL's date for having a weapon, but compared to the development time OTL's program that did not entirely exclude Brits took)

In which case, Klaus Fuchs would never have set foot inside Los Alamos.

Well that vector of compromise of secrets disappears, which is a good thing. How much would that set back the Soviets?

Once that bomb is dropped [on Germany], you get a push for peace from remaining soldiers

Can we just guarantee that? What if Hitler or regime hardliners or others who know they are dead men walking use totalitarian means to force the continuation of fighting?

However, using atom bombs (instead of HE and napalm) to destroy the likes of Dresden and Hanover, and Yokohama and Kobe more or less at the same time, might have helped convince both capitals that "there's plenty more where they came from". That is, just as we truly did make a quasi-bluff ( we really only had only one more bomb ready to go in August 45) and one or two a month after that, if we had the bombs earlier and still had two wars going, we would have built up a bare minimum of a stockpile before using them in both Europe and Japan and implying rapid continued production. These ideas are in Mangi, J. Dropping the Atomic Bomb on Hirohito and Hitler 2022 Pen & Sword.

Sounds like the way to go. And, vis-a-vis the Germans, it's not like conventional contact and attrition has stopped. And if the bluff fails, in a few months you'll have semi-mass production, then truly mass production, of the atomics.

 

[CalBear]

dramatic music

Who Summons the BEAR!!!

thunder of cymbals



The Manhattan Project was always, even before it had a name, understood to be a tool to be used against the Reich. Germany was clearly the more potent enemy and more serious threat. What was not anticipated was the issues surrounding the required delivery system. If Manhattan had presented a dozen Mk III bombs to the Allied High command in May 1, 1942 they could not have been used, not unless the willingness existed for a straight up suicide mission.


There was exactly one aircraft that could successfully deliver a 1st Generation. the specially modified versions of the B-29 known as "Silverplates". These aircraft (modified B-29B) were faster than the conventional bomber, a critical element in the eventual delivery method. The Lancaster was the only other bomber in squadron service that could handle the Bomb (along with the low production B-32), but it lacked both the operational ceiling and max speed needed to deliver the bomb and escape.

When Tube Alloys/Manhattan began literlly no one actually knew, even beyond if it could be done, what the eventual weight and likely yield of the weapon would be. The weight wound up being just short of five tons and the yield was expected to be in the 15-20 kT range. The yield provided a very clear picture of what sort of distance an aircraft would need to put between itself and the blast. To achieve the required distance a radical set of maneuvers was developed that stressed the modified B-29 to their limits, even then the aircraft were subjected to heavy turbulence from the bombs shock wave.

It is strikingly unlikely that the Bomb could have been delivered over the Reich, compared to Japan. The Japanese had ignored their anti-aircraft defense to a degree that, in hindsight, seem almost unimaginable, to the degree that aircraft over 30,000 feet were, while not safe, at relatively limited risk. The counbtry had also had reached the point that virtually all Avgas was being held for repelling the expected invasion. This combined meant that three plane elements of B-29s were almost literally ignored (at Hiroshima, the Japanese had actually sounded the "all Clear" from the original air raid warning since it was obviously only a couple weather planes). The Reich NEVER stopped defensing its airspace. Weather and BDA had to be conducted by high speed aircraft like the Mosquito or modified fighters that could get in and out before the Luftwaffe (both air and AAA) had a chance to react.

 

[marathag]

Well that vector of compromise of secrets disappears, which is a good thing. How much would that set back the Soviets?

Ted Hall sent info to the Soviets on processes for making bomb grade Plutonium, and details on the Fatman
Bomb.
He didn't know that Fuchs was also spying, and the Soviets pretty much used Fuchs to doublecheck what Hall was sending

 

[25thID]

The trend in this discussion towards assuming Germany is the first atomic target, or at most, debating whether the bomb is used simultaneously on Germany and Japan is ignoring one or two earlier detailed discussions on this subject. I summon thee @CalBear. There was extensive discussion about how Japan was easier to target with the weapon because of its weaker air defenses and habit of not challenging single aircraft that the Germans never conceded. I believe one of these discussions also noted that one of the earliest contemplated targets, rather than a Japanese or German city, was a Japanese fleet concentration or fleet facility at Truk lagoon in the west-central Pacific.

The factor in favor of emphasizing use against Germany early and often is the relatively more serious threat that the Germans could successfully develop their own atomic during the war than the Japanese could. (even though the threat isn't that serious). However, the argument for simultaneous use, or starting with Japan is that the small-ish number of atomic bombs available early is more likely to be a decisive killing blow against Japan than Germany, with less chance of the bomb delivery mission being intercepted or forced to abort or the bomb being captured.



Great question. See my speculations above. I would vote for at least simultaneous. Not for the domestic political reasons you suggest, but for practical strategic reasons of efficacy. If the the difference in starting use of the bomb between theaters is just a matter of a few weeks, I honestly can see FDR managing the politics of that fine, justifying that on a military urgency/expertise case.


Not really, as you later suggest, the pressure will be there to deliver results just as soon as possible.

exactly, because...

....bingo

interesting....would this come with a cost in efficiency or timeliness that delays completion of a usable weapon (maybe not compared to OTL's date for having a weapon, but compared to the development time OTL's program that did not entirely exclude Brits took)

Well that vector of compromise of secrets disappears, which is a good thing. How much would that set back the Soviets?

Can we just guarantee that? What if Hitler or regime hardliners or others who know they are dead men walking use totalitarian means to force the continuation of fighting?

Sounds like the way to go. And, vis-a-vis the Germans, it's not like conventional contact and attrition has stopped. And if the bluff fails, in a few months you'll have semi-mass production, then truly mass production, of the atomics.

In our history books, the Brits' role is minimized, but I believe you are quite correct to speculate about what effect an altered role for the Brits would have had. As Gowing (Britain and Atomic Energy) and others point out, the Brits' early nuclear insights were considerably in advance of what US was doing. After years of less-than-full partnership, the Brits who did work at almost all of the Manhattan Project sites made a wide range of valuable contributions. Although Groves almost dismissed their role when he wrote his Now It Can Be Told memoir, he was actually on record as having praised the Brits' role and had asked more than one to stick around after the war. The several accounts I've read indicate that the contribution of the Brits, especially at Los Alamos, got us the bomb probable a few months sooner than if they hadn't been there.

As to the degree of Fuchs' help to the Soviets, he is the most famous of the several known spies at Los Alamos who were from the UK, and he may or may not have been the most "effective". So I think it is fair to say that without UK involvement in Manhattan, and therefore without the help of the UK traitors, the Soviet bomb might have taken a little, but not much longer to develop. However, as much of this thread is saying, a few months plus or minus in the availability of atomic weapons could have had wide geopolitical consequences, as in, would a later Soviet bomb have affected the Chinese or Korean Wars?

 

[ivanotter]

The interesting part is if the bomb is available in '43, and being used, the targt would be Germany. But it could just as well have been shot down i believe.

 

[ivanotter]

But let us look at a plausible scenario:

Mid 1943:
Kursk is going full tilt
Scicily invaded

The target is Hamburg (over water flight).

Will the german generals call it quits? or will another bomb do it

 

[DennisMSullivan]

I enjoyed this book:
The Berlin Project by Gregory Benford.

The bomb is ready to use by June 6, 1944.

 

[hammo1j]

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.

My guess with air superiority as it was at the time would be a B29 night drop with turrets removed to prevent strain on the 3350s.

If no B29, the Lancaster would have to be a Mark IV or Lincoln as the Mk III could not make 30k feet.

In either case you would need Mosquito or P61 escorts as the German NF force was still potent.

 

[Horton229]

I'm not sure one or two bombs is going to do it for Germany. If this is the case, the question re: stockpiling or using as/when available becomes more pressing.

Another consideration - as mentioned above by CalBear, German airspace was a very different proposition in 1944 vs. Japan in 1945 (or at any time). The fear of losing a weapon would be huge, even if the German's have no effective way of delivering it. The ferocious power of these weapons is no longer a theory, and London is far too close for comfort.

 

[Pesterfield]

The fear of losing a weapon would be huge, even if the German's have no effective way of delivering it.

Arm the bomb before reaching Germany and if they feel they're going to be shot down just drop it?
Might lead to a few failed missions and some small towns or countryside being nuked.

If anyone anticipates that it goes to the argument for building up a stockpile first.

 

[raharris1973]

The Manhattan Project was always, even before it had a name, understood to be a tool to be used against the Reich. Germany was clearly the more potent enemy and more serious threat.

There was exactly one aircraft that could successfully deliver a 1st Generation. the specially modified versions of the B-29 known as "Silverplates".

It is strikingly unlikely that the Bomb could have been delivered over the Reich, compared to Japan.

Well that's quite the rub then, isn't it?

Imagine the bomb is available at various early intervals:
6 months early - February 1945
1 year early - August 1944
18 months early - February 1944
2 years early - August 1943?

When was the Silver-plate B-29 and escape tactic first available?

Assuming that sticks to OTL's schedule

Is your third statement, "It is strikingly unlikely that the Bomb could have been delivered over the Reich, compared to Japan." categorical? German air defense is too formidable at late as the final months, weeks, days of the 3rd Reich, February-March 1945, for an atomic bombing to be executed on on a German target in Germany?

Would the B-29 and sufficiently close bases have been available to hit the Japanese targets in the home islands by February 1945? What about August 1944? If technology and range existed, were air defenses sufficiently degraded?

If the Allies are sitting on ready atomic bombs 6 months, a year, or two years earlier than OTL, unable to decisively employ them, is there any way they can anticipate the delivery system problem, make the B-29 available earlier and degrade air defenses earlier?

Can they come up with an alternate delivery solution. Or find super high-value, exposed German or Japanese military targets not on Japanese or German soil, they can employ bombs against, possibly at sea or on highly militarized outlying islands?