Mark 17 Bomb
The first Practical thermonuclear bomb
The Mark-17 was the physically largest nuclear bomb ever produced by the United States. Here it is placed against the backdrop of the enormous B-36, the only plane capable of carrying it. Located at the National Museum of the US Air Force, in Dayton, Ohio.
The Mark-17 is enormous, and heavy. The metal on the casing is three and a half inches thick, which accounts for its 42,000 lb weight. Photo made at the National Museum of the US Air Force, in Dayton.
The Mark-17 was followed quickly by the Mary 24, a bomb which used the same casing but offered less explosive power. Authors differ on exactly how this lower power was achieved (Gibson says the primaries differ, Goetz says that only the level of enrichment of the fuel differs). This unit is at the Nuclear Museum, in Albuquerque.
The Castle Air Museum in California also has a Mark-17 displayed next to their B-36 bomber. The bomb reportedly used a multiple parachute system to slow its descent to allow the bomber a chance to escape the blast. The bomb, with parachutes, took two minutes to descend from 36,000 feet (where it was released) to 8,000 feet, where it would detonate.
Reportedly the B-36 could carry an additional, smaller, nuclear bomb in its forward bomb Bay Area, with which to strike a secondary target. This image was made at the Castle Air Museum in Atwater, California.
Explosive Power
15 Megatons
Hiroshima Equivalent Factor
1000x
Dimensions
24 feet, 8 inches x 61 inches
Weight
Approx. 42,000 lbs.
Year(s)
1954-1957
Purpose
A much bigger bang.
Nukemap
NUKEMAP is a web-based mapping program that attempts to give the user a sense of the destructive power of nuclear weapons. It was created by Alex Wellerstein, a historian specializing in nuclear weapons (see his book on nuclear secrecy and his blog on nuclear weapons). The screenshot below shows the NUKEMAP output for this particular weapon. Click on the map to customize settings.
Videos
Click on the Play button and then the Full screen brackets on the lower right to view each video. Click on the Exit full screen cross at lower right (the “X” on a mobile device) to return.
Further Reading
- Wikipedia, Wikipedia (Mark 24), Global Security
- If you include test weapons, the first thermonuclear “bomb” appears to have been the Mark 14, an experimental model. Five units were built in 1954 but it was never deployed.
- The Atomic Heritage Foundation has a good, short history of the development of thermonuclear weapons.
- The Mark 17 was so large and heavy that only one Air Force bomber could carry it, the Convair B-36. It was replaced by the B52, which could not carry the Mark 17, and the huge bomb was phased out.
- A Mark 17 was accidentally dropped on Kirkland AFB in an accident that was revealed almost three decades after it occurred. The nuclear fuel “pits” had not been inserted but otherwise it was a fully functional weapon.
- There were several variations of the Mark 17, some intended to detonate mid-air (descending on parachutes to allow the bomber to try and get clear of the blast), while others were designed to explode on ground contact (surely also using parachute to slow the descent). Given the size of the blast I am dubious that an escape by the bomber would be possible, unless the bomb sat on the surface for a period of time.
- The Mark 17 is the most powerful nuclear weapon ever produced by the United States but not the most powerful one ever produced. The Soviets like to one-up the US and built a 100 megaton bomb, which they detonated at half-power.
- To Edward Teller, the great champion of developing thermonuclear weapons, 100 megatons was nothing. Bombs could be, and perhaps should be, made that were much more powerful. Note the sidebar graphic illustrating the relative explosive power of different nuclear weapons.
- The Mark 17 bomb is huge. Its size is hard to convey in photos when it is positioned against large bomber aircraft. If you want a better sense of scale this photo might help.
- This training bomb was found and transported to Kirtland AFB. But they don’t say where it was found.
- There have been 1054 nuclear tests by the United States and among the most famous in popular culture are the ones leading up to the Mark 17, especially the unexpectedly powerful Castle Bravo test (and the radiological disaster that followed) and the unexpectedly powerful Castle Romeo test (the test of the Mark 17 warhead). Romeo was the first detonated from a barge–the thermonuclear tests were so powerful they destroying the military infrastructure on the islands, not to mention the islands themselves.
- These tests, especially Bravo and the horrors of the Daigo Fukuryu Maru, are credited with the inspiration for Godzilla.
- While writing the essay (above) and making the calculations for Teller’s multi-gigaton bomb (and doubting my calculations) I stumbled on Alex Wellerstein’s blog post with the same calculations covering some of the same ground. Well worth reading.