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Mk5

Designer
Los Alamos (1943-1947)
Type
Implosion
Dimension(s)
128.5″ x ~43.75″
Yield
~6-120Kt
Application
(BOMB)  B5 Mod 0, 1, 2, 3
(WARHEAD)  W5 – Regulus I
(WARHEAD)  W5 – Matador

Weighing 3,300lbs1.1, 3.2(also cited as 3,000lbs5.1) and was 43.75″ in diameter and 128.5″ long3.1 (also cited as being 45-inches in diameter)5.2. With the B5 having a yield of 6 to 120Kt, it was deployed to aircraft carriers from 1952-1963 and the W5 having a yield of 10 to 45Kt, being deployed to submarines, aircraft carriers, and cruisers from 1959-1964.7.1 Used with the Matador (MGM-1) and Regulus I (SSM-N-8) cruise missiles.4.1, 7.1

Used the Type 110, 130, 150, 170, 190, 210, 240, 260 Capsule Assemblies when used as a gravity bomb10.1

Used the Type 210 Capsule Assembly when mated with Matador missile10.1

The W5 weighed 2,405lbs9.1

Deployed to:
Adak Naval Air Station, Alaska11.1
Chichi Jima, Japan11.1
Iwo Jima, Japan11.1

Decision was made at a meeting of the TX-5 Steering Committee on 27 January 1950, to develop a TX-5 bomb of 29″ high explosive (HE) diameter, having machined charges glued to the pit and to each other with a single bridge-wire detonator. During the first half of 1950 the following developments were made for pertinent components:8.1

  • Core Support; An exhaustive weight, strength, and vibration evaluation was made of various designs of core support structures, with the hollow cone construction showing the most promise. Final acceptance was to be made only after full-scale firing tests had been completed.8.1
  • Apple Core Insertion; Static stress and firing tests resulted in selection of a number of stainless steel tubes to serve as HE support and guidance for the apple core insertion scheme.8.1
  • Insertion Mechanism; A self-contained manual nose mechanism design was completed and a prototype placed under construction to facilitate placing the remotely stowed core into the mechanism. Special two handled trap door and capsule (TDC) container was designed.8.1
  • Detonator and Chimney Pad; A smaller single bridge-wire detonator and simplified chimney pad and piloted guide tube was developed. The detonator was undergoing reliability tests.8.1
  • HE Sphere Case; A light-weight sphere case was designed and put under static stress tests.8.2
  • Ballistic Case; A prototype light weight case (including fins) was procured from Douglas Aircraft for use in a ballistic drop program. The smaller detonator permitted reduction of the outside diameter of this case from 45″ to 43.75″8.2
  • Firing Units; Evaluation was under way for the single circuit, 2000v, 32 mFd (microfarad) unit; the low voltage, low capacity two channel unit; and the dual channel 32mFd unit, primarily intended for use in the Greenhouse tests.8.2
  • Switches; Progress was made on development of a mechanically operated contact switch, with satisfactory preliminary test results. Fabrication of a withdrawing puncture switch was in progress. Both switches were to be tested in three firing sets.8.2
  • Fuzing; There was no significant progress in fuzing, other than the impression that fuzing developments for the Mk4 Mod 1 bomb would be refined for use on the TX-58.3

The Mk5 Mod 0 begins being stockpiled June 1st 1951, the Mod 1 in November 1952, Mod 2 June 1954, and Mod 3 in January of 1955.3.1

Used the “Tom” initiator.2.1

(Background) Two Mk5 bombs removed from their H-46 shipping container. (Foreground) Mk12 bomb being removed from its container with its tail assembly being removed from its container on the right.
Technician removes the H-46 shipping container mounting ring from the handling gear for the Mk5
Mk5 bomb on the USS Ranger (CVA-61) Aircraft Carrier. Note the tail fins in their shipping configuration
Mk5 mounted in the special weapons storage area aboard the USS Ranger aircraft carrier
Mk5 in its H-46 shipping container
Mk5 Bomb (Albuquerque Nuclear Museum)
Mk5 Bomb (Albuquerque Nuclear Museum)
Mk5 with a Mk61. Note the M-102 capsule ball storage container on the left.
Clip of the in-flight-insertion mechanism within the nose of the Mk5. Note the how the nose must open to accommodate insertion.
Mk5 stowed aboard a ship
  1. Sandia National Laboratory Information Research Division 3434. (1967). History of the Mk7 Bomb (RS 3434/5). https://osf.io/46sfd/
    1. p.5
  2. Hansen, C. (1988). US Nuclear Weapons: The Secret History. http://www.worldcat.org/oclc/16404602
    1. p.35
  3. Sandia National Laboratory Information Research Division 3434. (1967). History of the Mark 5 Bomb (RS 3434/2). https://osf.io/46sfd/
    1. p.5
    2. p.16
  4. Sandia National Laboratory. (1998). Survey of Weapon Development and Technology (No. WR708; p. 650). http://fissilematerials.org/library/snl98.pdf
    1. p.86
  5. Johnson, L. (1997). Sandia National Laboratory: A History of Exceptional Service in the National interest (No. SAND97-1029). http://large.stanford.edu/courses/2018/ph241/blair1/docs/sand-97-1029.pdf
    1. p.74
    2. p.36
  6. Office of the Deputy Assistant Secretary of Defense for Nuclear Matters. (2020). Nuclear Matters Handbook 2020. https://www.acq.osd.mil/ncbdp/nm/nmhb/docs/NMHB2020.pdf
    1. p.42
  7. Norris, Robert S., Kristensen, Hans M. (2016). Declassified: US Nuclear Weapons at Sea During the Cold War. Bulletin of the Atomic Scientists, 72(1–5). https://www.tandfonline.com/toc/rbul20/72/1?nav=tocList
    1. p.60 (PDF Page)
  8. Defense Atomic Support Agency. (1959). First History of AFSWP 1947-1954: Volume 3, 1950: Chapter 4—Sandia Base (Vol. 3). https://ntrl.ntis.gov/NTRL/dashboard/searchResults/titleDetail/PB99143745.xhtml
    1. p.220 (PDF Page)
    2. p.221 (PDF Page)
    3. p.222 (PDF Page)
  9. Germain, L. S. (1991). The Evolution of U.S. Nuclear Weapons Design: Trinity to King (Historical Report LA-11403; p. 28). Los Alamos National Laboratory. https://osf.io/46sfd/
    1. p.22 (PDF Page)
  10. Office of the Assistant to the Secretary of Defense. (1978). History of the Custody and Deployment of Nuclear Weapons: July 1945 through September 1977. https://nsarchive2.gwu.edu//news/19991020/04-01.htm
    1. p.336 (PDF Page)
  11. Norris, Robert S., et. al. (2000). Where They Were; How Much Did Japan Know?. Bulletin of the Atomic Scientists, 56(1–6), 457. https://www.tandfonline.com/toc/rbul20/56/1?nav=tocList
    1. p.13 (PDF Page)