The Atomic bombing of Germany 1945

There have been many threads discussing what if an atomic bomb was ready and used against Nazi Germany. I even started a discussion for planning a vignette on the subject. Finally I have come up with a story of a nuclear attack against Germany in February 1945. There have been many discussions about what if the bomb were ready a year earlier. I have decided to add that into this story as well. So this will be the story of what a nuclear attack on Nazi Germany might have looked like.

The POD here of course is that the Trinity test takes place in 1944. This is a work in progress so the exact date is coming. I will also cover how the B-29s come to be in England.

Yes there is a lot of hand waving going on to make this happen. I found that making the Manhattan Project accomplish it's mission earlier than OTL is a lot easier than making the war in Europe last till August 1945.
 
Part I
The Atomic Bombing of Germany 1945



Part I

13 February 1945

RAF Marham, Great Britain

At 9PM a field order arrived from 8th Air Force headquarters at High Wycombe (codename:”Pine Tree”) to the 509th Composite Group. The field order stated that tomorrow, 14 February 1945 the 509th, in conjunction with other units of the 8th Air Force would attack the city of Dresden. The field order was merely a formality. The 509th, under the command of the recently promoted Colonel Paul Tibbets, already knew it was going to attack Dresden. The bomber group had officially been formed two months ago for the purpose of dropping an atomic bomb on either Nazi Germany or Japan. In fact it was Colonel Tibbets who had notified Pine Tree of the target selection.

The 509th Group flew Silverplate B-29 Superfortresses. These were B-29s modified to carry an atomic bomb. The group was actually part of the Manhattan Project, America’s ultra secret atomic weapons program. The 509th consisted of a mix of Silverplate B-29s, normal B-29s and C-54 cargo planes. The group was actually split into two detachments, Detachments (“Det”) A and B. Seven modified Superforts were in England with Col. Tibbets. Seven other Silverplates were deployed to the Pacific island of Tinian. There they were preparing for a nuclear strike against the Japanese.

The 509th Composite Group Det. A was for administrative and operational security reasons part of the 73rd Bombardment Wing. The 73rd was the only B-29 Superfortress bomber outfit in England. It had arrived in England in September 1944 commanded by Brigadier General Emmett O’Donnell. Officially the 73rd was part of the 20th Air Force under the direct command of General Henry “Hap” Arnold, commander of the entire USAAF. The USAAF’s other three operational B-29 combat wings, the 58th, 313 and 314th were currently in the Mariana Islands bombing Japan as part of the 20th Air Force. The 73rd Wing was initially supposed to be a separate unit, the XXI Bomber Command. It was soon decided that it would be easier for the B-29s to be integrated into the operations of the 8th Air Force already in England.

Operation Matterhorn and Project Heavyweight

In 1941 the Army Air Force planned on deploying the then unbuilt B-29 Superfortress to England. This was changed in the summer of 1942 with AWPD (Army War Plan Division) 42. Due to production and development problems it looked like the B-29 would be unavailable for immediate service in Europe.

In January at the Casablanca Conference President Roosevelt expressed the idea of basing long range bombers in China. Roosevelt wanted to use long range bombers to attack the Japanese home islands. He also wanted to show support to Chaing Kai Shek in the war against the Japanese. The Allied Joint chiefs of Staff felt supporting an air offensive against Japan from China would be a logistical challenge. The Japanese had overrun Burma in 1942 cutting off China from overland supply. The only way to keep China in the war was by flying war supplies over the Himalaya Mountains

In November 1943 Allied leaders were going to meet at the Cairo Conference. As President Roosevelt was preparing to attend the conference he received a message from Brigadier General Leslie Groves, head of the Manhattan Project. Groves informed the President that an atomic bomb would be ready no later than the end of 1944. General Groves suggested that definite plans be made to use the weapon against Germany and Japan.

In October 1943, Brigadier General Kenneth B. Wolfe had developed Operation Matterhorn. Matterhorn was the plan to base a force of B-29s in China for the purpose of bombing Japan. At the time the operation would be the only way the Americans could strike at Japan itself, which was President Roosevelt’s wish. Matterhorn was projected to go into effect June 1, 1944. Hap Arnold considered it a temporary fix until the Mariana Islands were captured at a date still to be determined. President Roosevelt was going to announce Operation Matterhorn at the Cairo conference but now the situation changed with news of the availability of an atomic bomb.

Both Arnold and General Groves now believed it that the best course of action would be to have some B-29s in England as a contingency for use against Nazi Germany. At the time it was still believed that the Germans were making progress on their own atomic weapons program. One of the purposes of the Manhattan project was to counter the Germans. It was also becoming obvious that the B-29 would be the only American bomber capable of carrying an atomic weapon. Right now only 100 bombers had been built. The AAF needed to supply combat wings for service against Japan and also to deliver nuclear weapons. In keeping with the “Germany first” strategy there was now a way of knocking Hitler and the Nazis out of the war.

George Marshall, US Army Chief of Staff was not too happy with Operation Matterhorn sided with Arnold. Marshall convinced the President to move the Matterhorn deployment from China to the Mariana Islands. From there the United States would begin an air campaign against the Japanese empire. A B-29 combat wing would be deployed to England to be available in case it was needed. In order to placate the Chinese more air transport units and B-24 bombers would be sent to the China-Burma-India (CBI) Theater. Churchill was told of the planned deployment at Cairo. He endorsed the idea of very long range (VLR) bombers in England. Churchill however hoped that the bombers might be used against targets in eastern Europe, especially Poland if possible. He wanted to show support to the Poles. Stalin was informed of the Superfortresss at the Tehran Conference two days after the Cairo meeting. He was not informed of the atomic bomb. Stalin was very interested in the B-29. Unknown to both Churchill and Roosevelt, Russian intelligence knew about the plane and about the Manhattan Project as well.

Project Heavyweight became the codename to move the B-29s to Great Britain. In December 1943 an advance party was sent to England to survey airfield sites. The rest of the 8th Air Force bombers were stationed in Norfolk, England so the Superforts would join them there to simplify logistics. RAF airfields at Marham, Sculthorpe, Lakenheath were selected. North Pickenham, an airfield under construction for the USAAF was also selected. Construction of an airfield at Milisle, Northern Ireland was halted and construction assets were to be moved to Norfolk. Construction began in January 1944. Arnold wanted the airfields completed before an invasion of France scheduled in the spring of that year. The project became a priority for USAAF Aviation Battalions already in Britain.

To be continued........
 
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In his novel The Berlin Project, physicist Gregory Benford argues that the bomb could have been ready in 1944 if the Manhattan Project was conducted differently.
I admitted to hand waving. Let’s say the MAUD report isn’t ignored and the Manhattan Project has a run of good luck. They skip Thin Man and develop Fat Man. Think of this story as a training scenario.
 
Part II
Part II

The Manhattan Project

In August 1943 a scale model of the “Fat Man” bomb was dropped from a Navy TBF Grumman Avenger. This test took place at the Naval Proving Grounds in Dahlgren Virginia*. This test was arranged by Naval Captain William “Deke” Parsons, head of the Manhattan Project Ordnance Division. The test of the Fat Man bomb prototype was a success. In February 1944 Parsons repeated the test again. This time the testing was done at Muroc Army AirField in Southern California. The next month in March another scale model Fat Man bomb was dropped, this time from an actual B-29. Data from the March test was sent to Boeing so modifications could be made on the B-29.

In the Spring of 1944 work began on the modified B-29s now called “Silverplates”. This caused some controversy for the USAAF. In March Hap Arnold was fighting what became known as “The Battle of Kansas”. Arnold was trying to get the production level of combat ready Superforts up to make the number of bombers he needed. Every Silverplate B-29 now made meant one less B-29 being sent to a combat bomber wing.

In Los Alamos, New Mexico work continued on a Plutonium bomb. On Monday May 8, 1944 a rehearsal for testing the atomic device was held. Robert Oppenheimer, lead scientist for Manhattan wanted to make sure that the implosion type bomb would actually work. There were also concerns that a test would be wasting millions of taxpayer dollars as well as plutonium. Oppenheimer planned to use the rehearsal to test all procedures needed to detonate the device. That Monday 108 tons of TNT laced with radioactive material was successfully detonated*.

On Friday August 4, 1944 at 0302MT the world’s first nuclear explosion took place in Los Alamos. That same day another historical event took place. In the city of Amsterdam in Nazi occupied Holland, Anne Frank and her family were arrested by the Germans.



*OTL the test in Virginia was for the failed “Thin Man” prototype.

*I moved up the original Trinity rehearsal exactly one year and a day.
 
I realized that I forgot there were three B-29 wings in the Marianas in February 1945. The 314th Bombardment Wing arrived at North Field Guam in January 1945. I have corrected Part I of the story to reflect this.
 
Part III
Part III

From: “The Allies and the Atomic Bomb” Time Magazine 1995

“The Summer of 1944 has recently become considered one of the most controversial periods of World War II. The United States successfully tested a nuclear weapon on August 4, 1944, yet the first bomb was not dropped on Nazi Germany until February 14, 1945. On one side you have supporters of the Western Allie’s decision. They feel that Hitler would not have surrendered if the bomb was used right away. The Japanese would also have not been intimidated by one nuclear bomb being dropped on their ally.”

“On the other side are those who feel that Roosevelt and Churchill let the war against Nazi Germany go on longer than necessary. They note that in August 1944 the Germans liquidated the Lodz Ghetto and sent that of the Jews held there to Auschwitz. Also that month the Warsaw Uprising began. Some modern day Poles (both former communist and non-communist) consider not using the bomb against the Nazis that autumn one more betrayal by the western powers.”

“Japanese right-wing nationalists feel that the Americans were saving the bomb for them all along and that President Roosevelt only ordered the nuclear bombing of Germany after giving in to political pressure. (These same nationalists also say with a certain amount of pride that the Americans feared the Japanese people.)”
 
Part IV
Roosevelt’s Decision

On May 15, 1944 the week after the atomic test rehearsal, General Groves attended a meeting at The White House. Also at the meeting were Secretary of War Stimson, General Marshall and Admiral William Leahy, Chief of Staff to the President. General Arnold did not attend because he had suffered a heart attack on May 10th.

General Groves formally informed the President of the upcoming plan for a nuclear test in August. It was at this meeting that President Roosevelt made his decision on how the atomic weapons program would proceed. The atomic bomb would remain for now a top-secret deterrent against the Nazi atomic program. The upcoming invasion of Europe would not be postponed. Groves could not guarantee that the test in August would be 100% successful. Marshall felt that the allies had already invested too much time and resources in the invasion to delay it further and Roosevelt agreed with him. If the Germans retaliated against the invasion with what the President called “unfavorable means” then the use of atomic weapons would be considered. As for the Japanese the President wanted the US Military to start considering the atomic weapons as an alternative to invading Japan. Another meeting was scheduled for after whenever the D-Day invasion and the atomic test in August was made to hammer out a final military plan.
 
Part IV-B
Operation Overlord the invasion of France took place on June 6, 1944 in Normandy. General Marshall and a now recuperated General Arnold traveled to England to meet with General Dwight Eisenhower, allied supreme commander. In addition to visiting Normandy, the Generals also came to brief Eisenhower on the Manhattan project. They also came to brief Churchill on Roosevelt’s decision on the atomic bomb and get his reaction. Admiral William Purnell from the Manhattan Project accompanied Marshall and Arnold.

General Marshall met with Prime Minister Churchill at 10 Downing Street and told him of President Roosevelt’s decision. Churchill felt the bomb should be used as a first strike weapon against both the Nazis and Japanese but for now would back the President’s choice.

Admiral Purnell held a separate briefing for Eisenhower, General Carl “Tooey” Spaatz USAAF, commander of Strategic Air Forces Europe, and Charles Portal, Britain’s Chief of the Air Staff. Hap Arnold also attended. Purnell explained to them the basics of the Manhattan project and asked Portal for RAF support in delivering the bomb if needed. General Eisenhower was told by Arnold that the final decision to use the atomic bomb would be made by President Roosevelt in agreement with Prime Minister Churchill. Eisenhower and Spaatz were also told that the B-29s soon to arrive would be for use against strategic targets as part of the Twentieth Air Force. After the briefing Purnell traveled to East Anglia to inspect the future B-29 airfields.
 
Part V
Part V
On August 8th General Groves returned to The White House for final confirmation of the “military policy for the device”. There were additional members of this conference. Admiral Ernest King,Chief of Naval Operations was there. William Penney, head of the British delegation to the Manhattan Project was there to represent His Majesty’s government. General Arnold was now in attendance along with Brigadier General Haywood Hansell, selected to take command of XXI Bomber Command of the Twentieth Air Force. The XXI Bomber Command would be the B-29 force in Great Britain. Hansell had led the 1st Combat Wing of the VIII Bomber Command over Europe and helped plan the Combined Bomber Offensive (CBO). Arnold wanted Hansell to give input into how the new Superfortresses would be utilized to deliver an atomic bomb.

The meeting opened with the President and the other members viewing a film of the nuclear test brought to Washington by Groves. After this Secretary of War Stimson made the proposal that the atomic bomb not be used until enough bombs were produced to strike both Germany and Japan. President Roosevelt agreed with this. General Groves estimated that the Manhattan project could have a dozen Plutonium bombs manufactured by the end the year. He also reported that his scientists were now working on a Uranium bomb that would be ready at the around the same time. Groves closed by stating that a unit was being formed to train exclusively for dropping atomic bombs.

Heywood Hansell now briefed the members of the meeting. He told the members of the meeting that German air defenses were still formidable over Germany. No one had any idea how the B-29 would perform against German air defenses. There was also the fear that the Germans could possibly capture an unexploded atomic bomb. With that being said, his XXI Bomber Command would develop tactics to deal with the Luftwaffe. The Presence of Hansell’s bombers in Britain would not alert the Germans to Allies introducing a secret weapon against them.

In the Case of Japan, General Arnold asked that the capture of the islands of Iwo Jima and Okinawa be given priority over an invasion of Formosa. Arnold said his bombers would need fighter protection over Japan especially now that they would have to get an atomic bomb carrying Superfortress through. The Formosa invasion was cancelled.

A deadline was set to have the atomic bombs ready for use on Germany in December and on Japan in January 1945. The deadline for Japan was later changed to March 1945 once planning for the invasion of Iwo Jima began.

William Penney traveled to London with a copy of the atomic test film to brief Winston Churchill. Soon after Churchill sent a letter to Roosevelt where he stated he wanted RAF participation in any nuclear attack against Germany. Churchill also offered the use of British Lancaster bombers as a strike aircraft. The Prime Minister also inquired about using atomic bombs to retaliate for German V-1 and V-2 rocket attacks against Great Britain. Roosevelt urged the Prime Minister to be patient. Retaliation against the Nazis would be coming.

In Europe it looked like the war against Nazi Germany might end before the bomb arrived. Privately this is what Secretary of War Stimson hoped would happen. The Allies broke out of Normandy in late July before the first atomic test was carried out. In August Operation Dragoon, the landings in Southern France was carried out. Paris was liberated on August 25th and a German Army was destroyed in the Falaise Pocket. In September the situation changed. The Allied Armies bogged down along the German border. Operation Market Garden failed in Holland. In the east, the Russians stalled in Poland. The Warsaw uprising was crushed by the Nazis and it appeared that Stalin allowed that to happen.
 
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marathag

Banned
I admitted to hand waving. Let’s say the MAUD report isn’t ignored and the Manhattan Project has a run of good luck. They skip Thin Man and develop Fat Man. Think of this story as a training scenario.

Thinking of implosion earlier may get people thinking about imploding HEU as well as Pu, this accelerates the numbers of bomb cores that can be produced early on.
One Little Boy had enough material for over four implosion bombs

Postwar, most of the US stockpile was of composite cores, since Oak Ridge produced so much more material than Hanford.

Postwar, the US built more Gaseous Diffusion Plants besides K-25, being K-27, K-29, K-31 and K-33.

There was some delay in choosing the barrier material in 1943 that wasted about six months by itself, a simple PoD would be that Groves takes a gamble and picks the correct material at the start, and greenlights more Gaseous Diffusion Plants at the same time. That with imploding HEU, might give you the extra time needed
 
Thinking of implosion earlier may get people thinking about imploding HEU as well as Pu, this accelerates the numbers of bomb cores that can be produced early on.
One Little Boy had enough material for over four implosion bombs

Postwar, most of the US stockpile was of composite cores, since Oak Ridge produced so much more material than Hanford.

Postwar, the US built more Gaseous Diffusion Plants besides K-25, being K-27, K-29, K-31 and K-33.

There was some delay in choosing the barrier material in 1943 that wasted about six months by itself, a simple PoD would be that Groves takes a gamble and picks the correct material at the start, and greenlights more Gaseous Diffusion Plants at the same time. That with imploding HEU, might give you the extra time needed

What if this timeline’s Little Boy was an HEU bomb? I mentioned that Los Alamos is still working on a uranium bomb. Groves needs to produce as many bombs as possible.
How many composite cores can be produced each month?
 
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marathag

Banned
How many composite cores can be produced each month?

OTL, had the decision been made to use composite cores, around 20 cores would have been ready by the end of 1945 link

I have not been able to fix the date when Oak Ridge had produced just enough HEU to do a Trinity test
 
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