509th Operations Group

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509th Composite Group
509th Composite Group insignia patch
Active	December 17, 1944
Country	United States
Branch	United States Army Air Forces
Type	Composite bombardment group
Role	Nuclear Weapon Bombardment
Size	1767 personnel, 15 B-29 and 5 C-54 aircraft
Part of	313th Bomb Wing Twentieth Air Force
Garrison/HQ	North Field, Tinian, Mariana Islands
Motto	Defensor Vindex- Defender Avenger (Approved 10 Jul 1952)
Engagements	Hiroshima Nagasaki

The 509th Composite Group was an air combat unit of the United States Army Air Forces during the Second World War and as the 509th Operations Group, is a current unit of the United States Air Force. It was tasked with developing and employing a combat delivery system for the Atomic bomb and conducted the attacks on Hiroshima and Nagasaki, Japan, in August 1945.

The group later became a medium bombardment group of the Strategic Air Command, as the combat component of the 509th Bomb Wing, before being inactivated in 1952. Its lineage, honors, and history were also bestowed on the like-numbered wing in 1947.

After more than forty years of inactivation, the group was activated again as part of the 509th Bomb Wing and designated the 509th Operations Group, conducting the combat and training operations of the B-2 Spirit bomber.

Contents 1 Organization of the 509th Composite Group 1.1 Wartime command organization[1] 1.2 Squadron commanders 1.3 Component support organizations 2 History of the 509th Composite Group 2.1 Organization and training 2.2 Equipment and crews 2.3 Operational history 2.4 Atomic Bomb Missions 2.4.1 Mission compositions 2.5 Post-World War II history 2.6 Campaigns 2.7 Honors 2.8 Insignia 3 History of the 509th Operations Group, USAF 3.1 Organization 4 References 5 See also 6 Additional Sources

[edit] Organization of the 509th Composite Group

[edit] Wartime command organization^[1]

Position	Name	Dates of service
Group Commander	Col. Paul W. Tibbets,	December 17, 1944—January 22, 1946
Deputy Group Commander	Lt.Col. Thomas J. Classen	May 4, 1945—
Group Operations Officer (S-3)	Major James I. Hopkins, Jr.	December 17, 1944—
Group Executive Officer	Lt.Col. Gerald E. Bean	December 17, 1944—
Group Adjutant	Captain Thomas L. Karnes	December 17, 1944—

[edit] Squadron commanders

393rd Bomb Squadron (Very Heavy)

Wartime Commander	Date of command
Major Thomas J. Classen	March 12, 1944¹
Lt.Col. Paul W. Tibbets	September 14, 1944
Lt.Col. Thomas J. Classen	December 17, 1944
Major Charles W. Sweeney	May 4, 1945
Postwar Commander	Date of command
Lt.Col. Virgil M. Cloyd	July 1, 1946
Lt.Col. Phillip Y. Williams	June 1, 1948
Lt.Col. Robert B. Irwin	September 3, 1948
Lt.Col. Phillip Y. Williams	October 15, 1948
Lt.Col. James I. Hopkins	January 3, 1949
Lt.Col. Phillip Y. Williams	January 20, 1949
Lt.Col. Jack D. Nole	May 3, 1949
Lt.Col. Phillip Y. Williams	June 13, 1949
Lt.Col. William S. Martensen	June 30, 1949

¹The 393rd Bomb Squadron was part of the 504th Bomb Group (VH) from March 12, 1944, to September 14, 1944. 320th Troop Carrier Squadron

Commander	Date of command
Major Hubert J. Konopacki	December 17, 1944¹
Major Charles W. Sweeney	January 6, 1945
Captain John J. Casey, Jr.	May 4, 1945²

¹The 320th Troop Carrier Squadron was activated on December 17, 1944, and ²disbanded August 19, 1946.

[edit] Component support organizations

Unit	Commander	# of personnel
Headquarters and Base Services Squadron	Major George W. Westcott	99
390th Air Service Group	Lt.Col. John W. Porter	190
1027th Air Materiel Squadron	Major Guy Geller	140
603rd Air Engineering Squadron	Captain Earl O. Casey	225
1395th Military Police Company	Captain Louis Schaffer	127
1st Ordinance Squadron (Special, Aviation)	Major Charles F. Begg	298

[edit] History of the 509th Composite Group

[edit] Organization and training

The 509th Composite Group was constituted on December 9, 1944, and activated on December 17, 1944, at Wendover Army Air Field, Utah, commanded by Colonel Paul W. Tibbets. ^[2] Colonel Tibbets had been assigned to organize and command a combat group to develop the means of delivering an atomic weapon by airplane against targets in Germany and Japan. Because the flying squadrons of the group consisted of both bomber and transport aircraft, the group was designated as a "composite" rather than a "bombardment" unit.

Working with the Manhattan Engineering District at Site Y in Los Alamos, New Mexico, Tibbets had selected Wendover for his training base (over Great Bend, Kansas, and Mountain Home, Idaho)^[3] because of its remoteness. On September 10, 1944, the 393rd Bomb Squadron, a unit of B-29 Superfortresses, arrived at Wendover from the 504th Bomb Group (Very Heavy) at Fairmont Army Air Base, Nebraska, where it had been in group training since March 12. When its parent group deployed to the Marianas in early November 1944, the squadron was assigned directly to the Second Air Force until creation of the 509th CG.^[4] Originally consisting of twenty-one crews, fifteen were selected to continue training and were organized into three flights of five crews, lettered A, B, and C.

The 320th Troop Carrier Squadron, the other flying unit of the 509th, came into being because of the highly secret work of the group. The organization that was to become the 509th required its own transports for the movement of both personnel and materiel, resulting in creation of an ad hoc unit nicknamed "The Green Hornet Line".^[5][6] Crews for this unit were acquired from the six 393rd crews not selected to continue B-29 training, some of whom chose to remain with the 509th rather than be assigned to a replacement pool of the Second Air Force. They began using Curtiss C-46 Commandos and C-47 Skytrains already at Wendover and after November 1944 flew five acquired C-54 Skymasters.^[7] The 320th TCS was formally activated at the same time as the group.^[2]

Other support units were activated at Wendover from personnel already present and working with its Project W-47 (superseded by Project Alberta) or in the 216th Base Unit, both affiliated with the Site Y project. The 390th Air Service Group was created as the command echelon for the 603rd Air Engineering Squadron, the 1027th Air Material squadron, and its own Air Base Support Squadron, but as these units became independent operationally, acted as the basic support unit for the entire 509th Group in providing quarters, rations, medical care, postal service and other basic support functions. The 603rd AES was unique in that it provided depot-level B-29 maintenance in the field, obviating the necessity of sending aircraft back to the United States for major repairs. The 603rd made a number of modifications to the first contract order of Silverplate B-29s that were later incorporated as specifications for the combat models.^[8]

The 393rd Bomb Squadron began replacement of its original B-29s with modified Silverplate airplanes with the delivery of three in mid-October 1944.^[5] These aircraft had extensive bomb bay modifications and a "weaponeer" station installed, but initial training operations identified numerous other modifications necessary to the mission, particularly in reducing the overall weight of the airplane to offset the heavy loads it would be required to carry. Five more Silverplates were delivered in November and six in December, giving the group 14 for its training operations. In January and February 1945, 10 of the 15 crews under the command of the Group S-3 (operations officer) were assigned temporary duty at Batista Field, San Antonio de los Baños, Cuba, where they trained in long-range over-water navigation.^[9]

On March 6, 1945, the 1st Ordnance Squadron (Special, Aviation) was activated at Wendover, again from Army Air Forces personnel on hand or already at Los Alamos, and concurrent with the activation of Project Alberta. Its purpose was to provide trained personnel and special equipment to the group to enable it to assemble atomic weapons at its operating base, thereby allowing the weapons to be transported more safely in their component parts. A rigorous candidate selection process was used to recruit personnel, with reportedly an 80% "washout" rate, and those made a part of the unit were not permitted transfer until the end of the war, nor were they allowed to travel without escorts from Military Intelligence units.^[10] En route to Tinian at Mather Air Force Base in California, the commanding general of the base was told at gunpoint [1] he was not allowed on board The Great Artiste.

With the addition of the 1st Ordnance Squadron to its roster, the 509th CG had an authorized strength of 225 officers and 1,542 enlisted men, almost all of whom deployed to Tinian. The 320th TCS did not officially deploy but kept its base of operations at Wendover. In addition to its authorized strength, the 509th had attached to it on Tinian 51 civilian and military personnel of Project Alberta, and two representatives from Washington, D.C.,^[11] Brigadier Thomas Farrell (General Leslie Groves' executive officer) and Rear Admiral William R. Purnell of the Military Policy Committee.^[12]

The 509th began replacement of its 14 training Silverplates in February 1945 by transferring four to the 216th Base Unit. In April they began receiving Silverplates of the third modification increment and the remaining ten training B-29s were placed in storage. Each bombardier completed at least 50 practice drops of inert pumpkin bombs and Col. Tibbets declared his group combat-ready.^[13] Preparation for Overseas Movement (POM) began in April.

[edit] Equipment and crews

B-29, "ENOLA GAY", 44-86292. Dropped "LITTLE BOY", August 6, 1945, on Hiroshima

B-29, "BOCKSCAR", 44-27297. Dropped "FAT MAN", August 9, 1945, on Nagasaki

Combat B-29's of the 393rd Bomb Squadron

AAF serial #	Victor #	Name	Crew #	Airplane Commander	USAAF Delivery	Arr. Tinian	Tail Code
B-29-36-MO 44-27296	84	Some Punkins	B-7	Capt. James N. Price	March 19, 1945	June 14, 1945	Large A
B-29-36-MO 44-27297	77	Bockscar	C-13	Capt. Frederick C. Bock	March 19, 1945	June 17, 1945	Triangle N
B-29-36-MO 44-27298	83	Full House	A-1	Maj. Ralph R. Taylor	March 20, 1945	June 17, 1945	Square P
B-29-36-MO 44-27299	86	Next Objective	A-3	Capt. Ralph N. Devore	March 20, 1945	June 17, 1945	Triangle N
B-29-36-MO 44-27300	73	Strange Cargo	A-4	Capt. Joseph E. Westover	April 2, 1945	June 11, 1945	Large A
B-29-36-MO 44-27301	85	Straight Flush	C-11	Maj. Claude R. Eatherly	April 2, 1945	June 14, 1945	Triangle N
B-29-36-MO 44-27302	72	Top Secret	B-8	Capt. Charles F. McKnight	April 2, 1945	June 11, 1945	Large A
B-29-36-MO 44-27303	71	Jabit III	B-6	Maj. John A. Wilson	April 3, 1945	June 11, 1945	Large A
B-29-36-MO 44-27304	88	Up An' Atom	B-10	Capt. George W. Marquardt	April 3, 1945	June 17, 1945	Triangle N
B-29-40-MO 44-27353	89	The Great Artiste	C-15	Capt. Charles D. Albury	April 20, 1945	June 28, 1945	Circle R
B-29-40-MO 44-27354	90	Big Stink	A-5*	Lt.Col. Thomas J. Classen*	April 20, 1945	June 25, 1945	Circle R
B-29-45-MO 44-86291	91	Necessary Evil	C-14	Capt. Norman W. Ray	May 18, 1945	July 2, 1945	Circle R
B-29-45-MO 44-86292	82	Enola Gay	B-9	Capt. Robert A. Lewis	May 18, 1945	July 6, 1945	Circle R
B-29-50-MO 44-86346	94	Luke the Spook	C-12*	Capt. Herman S. Zahn*	June 15, 1945	August 2, 1945	Square P
B-29-50-MO 44-86347	95	Laggin' Dragon	A-2	Capt. Edward M. Costello	June 15, 1945	August 2, 1945	Square P

Source:Richard H. Campbell, The Silverplate Bombers, ISBN 0-7864-2139-8

*These crews and aircraft commanders switched airplane assignments on August 9, 1945

Although all of the B-29's were named as shown, the only nose art applied to the aircraft before the atomic bomb missions was that of Enola Gay. ^[14] With the exceptions of victors 71 and 94, the others were applied some time in August 1945. Luke the Spook was not named until November 1945, and it is not known if nose art was ever applied to Jabit III,^[15] although the version shown at the 509th Yearbook gallery was first shown in 1997.^[16]

Color images of 393rd Bomb Squadron nose art

[edit] Operational history

The ground support echelon of the 509th CG received movement orders in April 1945 and moved by rail to its port of embarkation at Seattle, Washington. On May 6 the support elements sailed on the SS Cape Victory for the Marianas. An advance party of the air echelon flew to North Field, Tinian, on May 18, where it was joined by the ground echelon on May 29, 1945, marking the group's official change of station.^[6] Project Alberta's "Destination Team" also sent most of its members to Tinian to supervise the assembly, loading, and dropping of the bombs under the administrative title of 1st Technical Services Detachment.^[17]

The air echelon began deploying from Wendover June 4, 1945, with the first B-29 arriving at North Field on June 11. The group was assigned to the 313th Bomb Wing, whose four groups had been flying missions against Japan since mid-February, but because of security considerations was given a base area near the airfield on the north tip of Tinian, several miles from the main installations in the center part of the island.^[6] Two of the group's bombers were not delivered by Martin-Omaha until early July and remained at Wendover until July 27 to act as transports to Tinian for two of the Fat Man atomic bomb assemblies.^[18]

The group was assigned tail markings of a circle outline around an arrowhead pointing forward, but at the beginning of August, after it began flying combat missions, its fifteen B-29's were given the tail markings of other XXI Bomber Command groups as a security measure. The victor numbers previously assigned the aircraft were changed to avoid confusion with B-29s of the groups from whom the tail identifiers were borrowed.^[19]

Victor numbers 82, 89, 90, and 91 (including the Enola Gay) carried the markings of the 6th Bomb Group (Circle R); victors 71, 72, 73, and 84 those of the 497th Bomb Group (large "A"); victors 77, 85, 86, and 88 those of the 444th Bomb Group (triangle N); and victors 83, 94, and 95 those of the 39th Bomb Group (square P).^[20]

After ground training for the combat crews, the 509th began operations on June 30, 1945, with a calibration flight involving nine of the B-29s on hand. During the month of July and the first eight days of August the thirteen bombers of the 393rd BS flew an intensive training and mission rehearsal program that consisted of:

• 17 individual training sorties without ordnance
• 15 practice bombing missions against Japanese-held Truk, Marcus, Rota, and Guguan, between July 1 and July 22 with 90 B-29s using 500- and 1000-pound bombs to practice mission procedures^[21]
• 12 combat missions against targets in Japan using high-explosive "pumpkin bombs", with 37 B-29s dropping conventional-bomb replications of the Fat Man between July 20 and July 29^[22]
• 8 component-tests and rehearsal drops of five inert Little Boy and three Fat Man assemblies between July 23 and August 8^[23]
• a practise mission to Iwo Jima on July 29 in which an inert Little Boy was unloaded and then reloaded to rehearse the contingency plan for using a back-up bomber in an emergency.^[24][25]

While this training was taking place, the disassembled components of the first two atomic bombs were transshipped to Tinian by various means. For the uranium bomb code-named Little Boy, the U-235 projectile and bomb pre-assemblies left Hunters Point Naval Shipyard, California, on July 16 aboard the cruiser USS Indianapolis, arriving July 26. That same day three C-54s of the 320th TCS left Kirtland Army Air Field each with one of the U-235 target rings and landed at North Field on July 28.^[26][27]

The components for the bomb code-named Fat Man all arrived by air. On July 26 the bomb's plutonium core (encased in its insertion capsule) and the beryllium-polonium initiator were transported from Kirtland by C-54 in the custody of Project Alberta couriers, also arriving July 28. The pre-assemblies of Fat Man F-31 were picked up by B-29 at Kirtland on July 28 and reached North Field on August 2.^[28]

The final item of preparation for the operation came on July 29, 1945. General Carl Spaatz, commanding all strategic bombers in the Pacific, arrived at Tinian with the order for the attack. Drafted by Brig.Gen. Leslie Groves and sent by Gen. George C. Marshall from Potsdam on July 25,^[29] the order designated four targets: Hiroshima, Kokura, Niigata, and Nagasaki, and ordered the attack to be made "as soon as weather will permit after about 3 August."^[30]

[edit] Atomic Bomb Missions

See Main Article: Atomic bombings of Hiroshima and Nagasaki

The mission profile for both atomic missions called for weather scouts to precede the strike force by an hour, reporting weather conditions in code over each proposed target. The strike force consisted of a bombing aircraft, with the aircraft commander responsible for all decisions in reaching the target and the bomb commander (weaponeer) responsible for all decisions regarding dropping of the bomb; a blast instrumentation aircraft which would fly the wing of the strike aircraft and drop instruments by parachute into the target area; and a camera ship, which would also carry scientific observers. Each mission would have one "spare" aircraft accompanying it as far as Iwo Jima to take over carrying the bomb if the strike aircraft encountered mechanical problems.

The Hiroshima mission was flown as planned and executed without significant problems or diversion from plan. The Nagasaki mission, however, originally targeted Kokura and encountered numerous problems which resulted in the bombing of the secondary target, a delay in bombing of almost two hours, detonation of the bomb some distance from the designated aiming point, and a diversion of the strike force to emergency landings on Okinawa because of a lack of fuel. However the basic objectives of the mission were met despite the problems.

Lieutenant Jacob Beser flew on both attack aircraft (the only man to do so), although Maj. Charles W. Sweeney and crew observed Hiroshima from The Great Artiste and dropped the bomb on Nagasaki from Bockscar. Lawrence H. Johnston of Project Alberta observed all three nuclear explosions, including the Trinity test.

[edit] Mission compositions

Special Mission 13, Primary target Hiroshima, August 6, 1945^[31]

Aircraft	Pilot	Call Sign	Mission role
Straight Flush	Maj. Claude R. Eatherly	Dimples 85	Weather reconnaissance (Hiroshima)
Jabit III	Maj. John A. Wilson	Dimples 71	Weather reconnaissance (Kokura)
Full House	Maj. Ralph R. Taylor	Dimples 83	Weather reconnaissance (Nagasaki)
Enola Gay	Col. Paul W. Tibbets	Dimples 82	Weapon Delivery
The Great Artiste	Maj. Charles W. Sweeney	Dimples 89	Blast measurement instrumentation
Necessary Evil	Capt. George W. Marquardt	Dimples 91	Strike observation and photography
Top Secret	Capt. Charles F. McKnight	Dimples 72	Strike spare—did not complete mission

Special Mission 16, Secondary target Nagasaki, August 9, 1945^[32]

Aircraft	Pilot	Call Sign	Mission role
Enola Gay	Capt. George W. Marquardt	Dimples 82	Weather reconnaissance (Kokura)
Laggin' Dragon	Capt. Charles F. McKnight	Dimples 95	Weather reconnaissance (Nagasaki)
Bockscar	Maj. Charles W. Sweeney	Dimples 77	Weapon Delivery
The Great Artiste	Capt. Frederick C. Bock	Dimples 89	Blast measurement instrumentation
Big Stink	Maj. James I. Hopkins, Jr.	Dimples 90	Strike observation and photography
Full House	Maj. Ralph R. Taylor	Dimples 83	Strike spare—did not complete mission

While the Nagasaki mission was in progress, two B-29's of the 509th took off from Tinian to return to Wendover. Lt.Col. Classen, the deputy group commander, in the unnamed victor 94 and crew B-6 in Jabit III, together with their ground crews, were sent back to stage for the possibility of transporting further bomb assemblies to Tinian.^[33] However the plutonium cores were still at Site Y, and on August 13 Gen. Groves ordered that all shipments of material be stopped. His order reached Los Alamos in time to keep the third bomb from being shipped.^[34] The first Atomic War lasted 9 days, August 6 through August 15, 1945.

After the Nagasaki mission the group continued combat operations, making another series of pumpkin bomb attacks (12 dropped) on August 14. With the announcement of the Japanese surrender, however, the 509th CG flew three further training missions involving 31 sorties on August 18, 20, and 22, then stood down from operations. The group flew a total of 210 operational sorties from June 30 to August 22, and aborted four additional flights, with only one aircraft failure to take off. 140 involved the dropping of live ordnance.^[35] 62 sorties received combat credits for missions flown (49 pumpkin bomb and 13 atomic bomb sorties).^[36]

[edit] Post-World War II history

In November 1945 the 509th Composite Group left Tinian and relocated to Roswell Army Air Field, New Mexico. The eight Silverplate bombers that had been delivered to Wendover in August also joined the group. Col. William H. Blanchard replaced Col. Tibbets as group commander on January 22, 1946, and also became the first commander of the 509th Bomb Wing.

The Group was assigned to Strategic Air Command on March 21, 1946, bring one of the first eleven organizations assigned to SAC. At the time SAC was formed, the 509th Composite Group was the only unit to have experience with nuclear weapons and thus is regarded by many historians as the foundation on which SAC was built. In April 1946 many of the group's aircraft deployed to Kwajalein as part of Operation Crossroads, a series of atomic bomb tests. The remainder became the core of two new squadrons activated as part of the group, the 715th Bomb Squadron and the 830th Bomb Squadron.

On July 10, 1946, the group was renamed the 509th Bombardment Group (Very Heavy) and the 320th TCS was disbanded. With the creation of the United States Air Force as a separate service, the group became the combat component of the 509th Bomb Wing on November 17, 1947, although it was not operational until September 14, 1948, when Col. John D. Ryan was named commander.

The group was redesignated as a medium bomb group in 1948 as part of the Strategic Air Command, and acquired an aerial refueling mission with the assignment of KB-29s. Its 27 operational Silverplate B-29s (the 309th had ultimately received 53 of the 65 produced) were transferred in 1949 to the 97th Bomb Wing at Biggs Air Force Base, El Paso, Texas, when the group converted to B-50 Superfortresses.

Its squadrons were removed on February 1, 1951, and assigned directly to the wing, effectively ending its operations. The 509th was inactivated on June 16, 1952 as part of a SAC (and later Air Force-wide) phase-out of groups.

[edit] Campaigns

  

World War II:

• Air Offensive, Japan
• Eastern Mandates
• Western Pacific

[edit] Honors

Department of the Air Force Special Order GB-294, dated 2 September 1999, awarded the Air Force Outstanding Unit Award (with Valor) to the 509th Composite Group for outstanding achievement in combat for the period 1 July 1945 to 14 August 1945.^[37]

[edit] Insignia

In addition to the official insignia the 509th Bomb Wing for B-2 stealth bomber test flights, based in Roswell, New Mexico, sported an informal insignia involving an alien, the legend "To Serve Man" (referring to a famous Twilight Zone episode) and the legend "Gustatus Similis Pullus" or "Tastes Like Chicken" (referring to the possible taste of long pig).^[38][39]

[edit] History of the 509th Operations Group, USAF

509th Operations Group
509th Operations Group
Active	July 15, 1993
Country	United States
Branch	United States Air Force
Type	Wing Operations Group
Role	B-2 Combat and Training Operations
Size	4 squadrons
Part of	Air Combat Command
Garrison/HQ	Whiteman Air Force Base, Missouri
Motto	Defensor Vindex

The group was redesignated 509th Operations Group on March 12, 1993, and activated on July 15 as the flying component of the 509th Bomb Wing at Whiteman Air Force Base, Missouri. The 509th is equipped with all 20 of the USAF's B-2 Spirit bombers and its 394th CTS also uses T-38 Talon trainers.

[edit] Organization

The 509th OG consists of four component squadrons:^[40]

• 393d Bomb Squadron

The 393rd BS ("Tigers"), a traditional squadron of the 509th, was activated as a B-2 squadron on August 27, 1993.

• 13th Bomb Squadron

Activated as the 325th Bomb Squadron on January 6, 1998, the squadron was re-designated the 13th BS by Air Combat Command on September 23, 2005. The 13th BS ("Grim Reapers") had previously been a squadron of the 7th Operations Group, flying B-1B Lancers.

• 394th Combat Training Squadron

A Flying Training Unit (FTU), the 394th CTS conducts all flying training connected with the B-2.

• 509th Operations Support Squadron

A non-flying squadron, the 509th OSS ("Hawks") controls all airfield activities at Whiteman.

[edit] References

[edit] See also

• Enola Gay
• Paul Tibbets
• Project Alberta
• Pumpkin bomb
• Silverplate

[edit] Additional Sources

• 509th Operations Group Official Site
• The Atomic Heritage Foundation The former Children of the Manhattan Project site apparently is defunct, and its data can be found at the "MPHPA Classic" menu button.

v • d • e Manhattan Project Project Sites Hanford Engineer Works · Oak Ridge, Tennessee · Los Alamos, New Mexico · Berkeley Radiation Laboratory · Chicago Metallurgical Laboratory · Trinity Test Site · Project Alberta · Project Ames · Dayton Project People Robert Oppenheimer · Leslie Groves · Enrico Fermi · David Bohm · Emilio Segrè · Edward Teller Related Articles Timeline of the Manhattan Project · History of nuclear weapons · Nuclear weapons and the United States · S-1 Uranium Committee · Chicago Pile-1 · X-10 Graphite Reactor · Y-12 National Security Complex · Operation Alsos · Smyth Report · 509th Operations Group · Fat Man · Little Boy · Atomic bombings of Hiroshima and Nagasaki (debate)