Mark 21 nuclear bomb
E865251
The Mark 21 nuclear bomb was a high-yield thermonuclear weapon developed and deployed by the United States during the early Cold War era.
All labels observed (1)
| Label | Occurrences |
|---|---|
| Mark 21 nuclear bomb canonical | 2 |
How this entity was disambiguated
This entity first appeared as the object of triple T10223469 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
NED1
Entity disambiguation (via context triple)
gpt-5-mini-2025-08-07
Target entity: Mark 21 nuclear bomb Context triple: [Nuclear bombs of the United States, hasPart, Mark 21 nuclear bomb]
-
A.
Mark 15 nuclear bomb
The Mark 15 nuclear bomb was an early U.S. thermonuclear weapon deployed in the 1950s, notable as one of the first lightweight, high-yield hydrogen bombs in the American arsenal.
-
B.
Mark 5 nuclear bomb
The Mark 5 nuclear bomb was an early American fission weapon developed in the 1950s, notable for its relatively compact, gun-type design and use in various U.S. military delivery systems during the early Cold War.
-
C.
Mark 7 nuclear bomb
The Mark 7 nuclear bomb was an early U.S. tactical fission weapon introduced in the 1950s, notable for being one of the first nuclear bombs with variable yield and compatibility with multiple aircraft.
-
D.
Mark 6 nuclear bomb
The Mark 6 nuclear bomb was an early American high-yield, implosion-type nuclear weapon deployed during the early Cold War era.
-
E.
Mark 12 nuclear bomb
The Mark 12 nuclear bomb was an early lightweight, high-yield thermonuclear weapon developed and deployed by the United States during the 1950s.
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
NED2
Entity disambiguation (via description)
gpt-5-mini-2025-08-07
Target entity: Mark 21 nuclear bomb Target entity description: The Mark 21 nuclear bomb was a high-yield thermonuclear weapon developed and deployed by the United States during the early Cold War era.
-
A.
Mark 15 nuclear bomb
The Mark 15 nuclear bomb was an early U.S. thermonuclear weapon deployed in the 1950s, notable as one of the first lightweight, high-yield hydrogen bombs in the American arsenal.
-
B.
Mark 5 nuclear bomb
The Mark 5 nuclear bomb was an early American fission weapon developed in the 1950s, notable for its relatively compact, gun-type design and use in various U.S. military delivery systems during the early Cold War.
-
C.
Mark 7 nuclear bomb
The Mark 7 nuclear bomb was an early U.S. tactical fission weapon introduced in the 1950s, notable for being one of the first nuclear bombs with variable yield and compatibility with multiple aircraft.
-
D.
Mark 6 nuclear bomb
The Mark 6 nuclear bomb was an early American high-yield, implosion-type nuclear weapon deployed during the early Cold War era.
-
E.
Mark 12 nuclear bomb
The Mark 12 nuclear bomb was an early lightweight, high-yield thermonuclear weapon developed and deployed by the United States during the 1950s.
- F. None of above. chosen
Statements (39)
| Predicate | Object |
|---|---|
| instanceOf |
US military equipment
ⓘ
nuclear bomb ⓘ thermonuclear weapon ⓘ |
| armsControlStatus | retired before modern arms control treaties applied ⓘ |
| classification | gravity bomb ⓘ |
| compatibleAircraft |
B‑36 bomber
ⓘ
linked to:
Convair B-36 Peacemaker
B‑47 bomber ⓘ
linked to:
B-47 Stratojet
B‑52 bomber ⓘ |
| configuration | free‑fall bomb ⓘ |
| countryOfOrigin |
United States
ⓘ
linked to:
United States of America
|
| deliveryPlatform | strategic bomber ⓘ |
| deploymentContext | early Cold War strategic arsenal ⓘ |
| deploymentRole | strategic deterrent ⓘ |
| deploymentStart | 1955 ⓘ |
| designBasis |
Ivy Mike device
ⓘ
linked to:
Ivy Mike
TX‑21 design ⓘ |
| designedIn |
United States
ⓘ
linked to:
United States of America
|
| developedBy |
United States
ⓘ
linked to:
United States of America
United States Atomic Energy Commission ⓘ |
| developedFor | United States Air Force ⓘ |
| era | Cold War ⓘ |
| fuelType | fusion‑boosted thermonuclear fuel ⓘ |
| historicalSignificance | early high‑yield US thermonuclear weapon ⓘ |
| natoCategory | strategic nuclear weapon ⓘ |
| nuclearWeaponType | two‑stage thermonuclear ⓘ |
| numberBuilt | on the order of several hundred units ⓘ |
| purpose | mass‑destruction weapon ⓘ |
| replacedBy | Mark 36 nuclear bomb ⓘ |
| retired | late 1950s ⓘ |
| safetyFeatures | conventional high explosive implosion system ⓘ |
| serviceEntry | 1955 ⓘ |
| stageCount | two‑stage ⓘ |
| testStatus | design tested in US thermonuclear test series ⓘ |
| usedAsBasisFor | W21 warhead ⓘ |
| usedBy | United States Air Force ⓘ |
| warheadDesignation | W21 ⓘ |
| weightClass | heavy bomb ⓘ |
| yield | approximately 4 megatons of TNT ⓘ |
| yieldRange | 4–5 megatons of TNT ⓘ |
How these facts were elicited
The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.
Instruction
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10. # Requirements - If you don't know the subject at all, return an empty list. - If the subject is not a named entity, return an empty list. - Include at least one triple where predicate is "instanceOf". - Do not get too wordy. - Separate several objects into multiple triples with one object.
Input
Subject: Mark 21 nuclear bomb Description of subject: The Mark 21 nuclear bomb was a high-yield thermonuclear weapon developed and deployed by the United States during the early Cold War era.
Referenced by (2)
Full triples — surface form annotated when it differs from this entity's canonical label.