View source for Mark 24 nuclear bomb

{{Infobox weapon
| name               = Mark 24 nuclear bomb
| image              = Mk17 bomb.jpg
| image_size         = 300
| alt                = 
| caption            = A Mk-17 or Mk-24 bomb (casings are identical)
| type               = Thermonuclear gravity bomb
| origin             = United States
<!-- Type selection -->
| is_explosive       = yes
<!-- Service history -->
| service            = 1954-1956
| wars               = [[Cold War]]
<!-- Production history -->
| designer           = [[Los Alamos National Laboratory]]
| design_date        = 1954
| manufacturer       = 
| unit_cost          = 
| production_date    = '''EC-24:''' Mar-Oct 1954<br>
'''Mk-24:''' Jul 1954-Nov 1955
| number             = '''EC-24:''' 10<br>
'''Mk-24:''' 105
<!-- General specifications -->
| mass               = '''EC-24:''' {{cvt|39600|lb|kg}}<br>
'''Mk-24:''' {{cvt|41400-42000|lb|kg}}
| length             = {{convert|24|ft|8|in|m}} 
| diameter           = {{convert|61.4|in|m}}
<!-- Explosive specifications --> 
| filling            = 
| filling_weight     = 
| detonation         = [[Air burst]]
| yield              = '''EC-24:''' {{cvt|	13.5|MtTNT|PJ}}, [[Castle Yankee|Castle Yankee test]]<br>
'''Mk-24:''' {{cvt|15|MtTNT|PJ}}
}}{{Short description|American thermonuclear bomb design}}
The '''Mark 24 nuclear bomb''' was an American [[thermonuclear bomb]] design, based on the third American thermonuclear bomb test, [[Castle Yankee]].  The Mark 24 bomb was tied as the largest weight and size nuclear bomb ever deployed by the United States, with the same size and weight as the [[Mark 17 nuclear bomb]] which used a very similar design concept but unenriched lithium.

The Castle Yankee thermonuclear test was the first bomb to use lithium enriched with the [[Isotopes of lithium#Isotope separation|lithium-6]] isotope, up to perhaps 40% enrichment (the earlier [[Castle Bravo]] test had used the same enriched lithium combination but was not weaponised i.e. was not built as a deployable bomb).  The device tested was called the '''Runt II''' design; it was reportedly very similar to the Runt design tested in [[Castle Romeo]], other than the enrichment level.

Castle Yankee had a demonstrated yield of 13.5 [[TNT equivalent|megatons]].  The yield for the weaponized Mark 24 was predicted to be 10–15 megatons.

The EC24 bomb was a limited production run of the Castle Yankee test device, with 10 produced and stockpiled through 1954.  The EC24 was {{convert|61|by|255|in|m|2}} and weighed {{convert|39600|lb|kg|-2}}. The EC24 was a purely free-fall bomb design.

==Design==
The production model Mark 24 nuclear bomb was {{convert|61.4|by|296|in|m}} long, with a weight between {{convert|41000|and|42000|lb|kg|-2}}.  It was in service between 1954 and 1956, with a total of 105 units produced.  The Mark 24 included a {{convert|64|ft|m|adj=mid|-diameter}} parachute to slow its descent.

The bomb used manual in-flight insertion (IFI) that required a crewmember to crank a handle that was inserted into a hole in the nose of the bomb. This process inserted the weapon's pit into the implosion assembly.<ref>{{Cite report| publisher = Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)| last1 = Crompton, J| last2 = Kohut, F A| title = Aircraft Modification for the Mk 17 and the Mk 24 Atomic Bombs| accessdate = 2022-11-19| date = August 1958| url = https://www.osti.gov/opennet/detail?osti-id=16340165| page = 11| archive-date = 2022-11-19| archive-url = https://web.archive.org/web/20221119055752/https://www.osti.gov/opennet/detail?osti-id=16340165| url-status = live}}</ref>

==Survivors==
A Mark 24 casing is on display in the [[Castle Air Museum]] in [[Atwater, CA]].

==See also==
* [[List of nuclear weapons]]
* [[Nuclear weapon design]]
* [[Teller-Ulam design]]
* [[Mark 17 nuclear bomb]]
* [[Castle Yankee]]

==References==
{{reflist}}

* [http://nuclearweaponarchive.org/Usa/Weapons/Allbombs.html Allbombs.html] list of all US nuclear warheads at [http://nuclearweaponarchive.org nuclearweaponarchive.org]
* Chuck Hansen, ''U. S. Nuclear Weapons: The Secret History'' (Arlington: AeroFax, 1988)

{{United States nuclear devices}}

[[Category:Cold War aerial bombs of the United States]]
[[Category:Nuclear bombs of the United States]]
[[Category:Military equipment introduced in the 1950s]]