Tsar Bomba - Analysis

Analysis

The Tsar Bomba is the single most physically powerful device ever used by man. By contrast, the largest weapon ever produced by the United States, the now-decommissioned B41, had a predicted maximum yield of 25 Mt, and the largest nuclear device ever tested by the United States (Castle Bravo) yielded 15 Mt (this was due to an unexpected runaway lithium-7 reaction; the design yield was approximately 5 Mt). The largest weapons deployed by the Soviet Union were also around 25 Mt, as in the SS-18 Mod. 2 ICBM warheads.

The weight and size of the Tsar Bomba limited the range and speed of the specially modified bomber carrying it and ruled out its delivery by an ICBM (although on December 24, 1962, a 50 Mt ICBM warhead developed by Chelyabinsk-70 was detonated at 24.2 Mt to reduce fallout). Much of its high-yield destructiveness was inefficiently radiated upwards into space. It has been estimated that detonating the original 100 Mt design would have released fallout amounting to about 25 percent of all fallout emitted since the invention of nuclear weapons. Hence, the Tsar Bomba was an impractically powerful weapon. It was decided that a full 100 Mt detonation would create too great a risk of nuclear fallout, as well as a near certainty that the release plane (and crew) would be destroyed before it could escape the blast radius.

The Tsar Bomba was the culmination of a series of high-yield thermonuclear weapons designed by the Soviet Union and the United States during the 1950s (examples include the Mark-17 and B41). Such bombs were designed because:

• The nuclear bombs of the day were large and heavy, regardless of yield, and could only be delivered by strategic bombers. Hence yield was subject to dramatic economies of scale;
• It was feared that many bombers would fail to reach their targets because their size and low speed made detection and interception easy. Hence maximizing the firepower carried by any single bomber was considered vital;
• Before satellite intelligence each side lacked precise knowledge of the location of the other's military and industrial facilities;
• A bomb dropped without benefit of advanced inertial navigation systems could easily miss its intended target. Parachute retardation would only worsen the bomb's accuracy.

Thus certain bombs were designed to destroy an entire large city even if dropped five to ten kilometers from its center. This objective meant that yield and effectiveness were positively correlated, at least up to a point. However, the advent of ICBMs accurate to 500 meters or better made such a design philosophically obsolete. Subsequent nuclear weapon design in the 1960s and 1970s focused primarily on increased accuracy, miniaturization, and safety. The standard practice for many years has been to employ multiple smaller warheads (MIRVs) to "carpet" an area, resulting in greater ground damage.