Operation Hardtack II
E412150
Operation Hardtack II was a 1958 series of U.S. nuclear tests conducted primarily at the Nevada Test Site to evaluate a range of warhead designs and effects during the Cold War.
All labels observed (1)
| Label | Occurrences |
|---|---|
| Operation Hardtack II canonical | 4 |
How this entity was disambiguated
This entity first appeared as the object of triple T4080576 — 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: Operation Hardtack II Context triple: [United States nuclear weapons testing, hasPart, Operation Hardtack II]
-
A.
Operation Hardtack I
Operation Hardtack I was a 1958 U.S. series of high-yield nuclear tests in the Pacific, notable for advancing thermonuclear weapons development during the Cold War.
-
B.
Operation Castle
Operation Castle was a series of high-yield U.S. thermonuclear weapon tests conducted in the Pacific Proving Grounds during the early Cold War.
-
C.
Operation Redwing
Operation Redwing was a 1956 U.S. series of atmospheric nuclear tests in the Pacific Proving Grounds designed to evaluate advanced thermonuclear weapon designs and delivery systems.
-
D.
Operation Greenhouse
Operation Greenhouse was a series of early Cold War U.S. nuclear tests conducted in 1951 at Enewetak Atoll to advance thermonuclear weapon design and improve bomb efficiency.
-
E.
Operation Crossroads
Operation Crossroads was a series of U.S. nuclear weapons tests conducted at Bikini Atoll in 1946 to study the effects of atomic bombs on warships and military equipment.
- 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: Operation Hardtack II Target entity description: Operation Hardtack II was a 1958 series of U.S. nuclear tests conducted primarily at the Nevada Test Site to evaluate a range of warhead designs and effects during the Cold War.
-
A.
Operation Hardtack I
Operation Hardtack I was a 1958 U.S. series of high-yield nuclear tests in the Pacific, notable for advancing thermonuclear weapons development during the Cold War.
-
B.
Operation Castle
Operation Castle was a series of high-yield U.S. thermonuclear weapon tests conducted in the Pacific Proving Grounds during the early Cold War.
-
C.
Operation Redwing
Operation Redwing was a 1956 U.S. series of atmospheric nuclear tests in the Pacific Proving Grounds designed to evaluate advanced thermonuclear weapon designs and delivery systems.
-
D.
Operation Greenhouse
Operation Greenhouse was a series of early Cold War U.S. nuclear tests conducted in 1951 at Enewetak Atoll to advance thermonuclear weapon design and improve bomb efficiency.
-
E.
Operation Crossroads
Operation Crossroads was a series of U.S. nuclear weapons tests conducted at Bikini Atoll in 1946 to study the effects of atomic bombs on warships and military equipment.
- F. None of above. chosen
Statements (49)
| Predicate | Object |
|---|---|
| instanceOf |
United States military operation
ⓘ
nuclear test series ⓘ |
| codename | HARDTACK II ⓘ |
| context |
United States–Soviet nuclear arms race
ⓘ
linked to:
Cold War
|
| country |
United States
ⓘ
linked to:
United States of America
|
| endDate | 1958-10-31 ⓘ |
| followedBy | Operation Nougat ⓘ |
| location |
Nevada Test Site
ⓘ
linked to:
Nevada National Security Site
|
| militaryBranchInvolved |
United States Air Force
ⓘ
United States Army ⓘ United States Navy ⓘ |
| numberOfTests | 37 ⓘ |
| operator |
United States Atomic Energy Commission
ⓘ
United States Department of Defense ⓘ
linked to:
Department of Defense
|
| partOf |
1958 United States nuclear test series
ⓘ
United States nuclear weapons testing program ⓘ
linked to:
United States nuclear weapons testing
|
| precededBy | Operation Hardtack I ⓘ |
| purpose |
low-yield device testing
ⓘ
safety experiments ⓘ warhead design evaluation ⓘ weapons development ⓘ weapons effects testing ⓘ |
| relatedTo |
Nevada Test Site
ⓘ
linked to:
Nevada National Security Site
Partial Test Ban Treaty ⓘ
linked to:
Partial Nuclear Test Ban Treaty
|
| startDate | 1958-09-19 ⓘ |
| testSeriesIn | Nevada Proving Ground ⓘ |
| testSite |
Area 1 of Nevada Test Site
ⓘ
linked to:
Yucca Flat
Area 10 of Nevada Test Site ⓘ
linked to:
Yucca Flat
Area 18 of Nevada Test Site ⓘ
linked to:
Nevada Proving Ground
Area 19 of Nevada Test Site ⓘ
linked to:
Nevada Proving Ground
Area 2 of Nevada Test Site ⓘ
linked to:
Nevada Proving Ground
Area 20 of Nevada Test Site ⓘ
linked to:
Yucca Flat
Area 3 of Nevada Test Site ⓘ
linked to:
Nevada Proving Ground
Area 30 of Nevada Test Site ⓘ
linked to:
Nevada National Security Site
Area 31 of Nevada Test Site ⓘ
linked to:
Nevada National Security Site
Area 32 of Nevada Test Site ⓘ
linked to:
Nevada Proving Ground
Area 4 of Nevada Test Site ⓘ
linked to:
Nevada Proving Ground
Area 42 of Nevada Test Site ⓘ
linked to:
Yucca Flat
Area 7 of Nevada Test Site ⓘ
linked to:
Yucca Flat
Area 9 of Nevada Test Site ⓘ
linked to:
Yucca Flat
Nevada Test Site ⓘ
linked to:
Nevada National Security Site
|
| testType |
atmospheric nuclear test
ⓘ
balloon shot ⓘ tower shot ⓘ underground nuclear test ⓘ underground shaft test ⓘ |
| timePeriod | Cold War ⓘ |
| year | 1958 ⓘ |
| yieldRange | sub-kiloton to tens of kilotons ⓘ |
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: Operation Hardtack II Description of subject: Operation Hardtack II was a 1958 series of U.S. nuclear tests conducted primarily at the Nevada Test Site to evaluate a range of warhead designs and effects during the Cold War.
Referenced by (4)
Full triples — surface form annotated when it differs from this entity's canonical label.