The original Zeus A was similar to the original Hercules, but featured a revised control layout and gas puffers for maneuvering at high altitudes where the atmosphere was too thin for the aerodynamic surfaces to be effective.
The Zeus B interceptor was longer at 14.7 metres (48 ft), 2.44 metres (8 ft 0 in) wide, and 0.91 metres (3 ft 0 in) in diameter.
This was so much larger than the earlier Hercules that no attempt was made to have them fit into the existing Hercules/Ajax launchers.
Instead, the B models were launched from silos, thus the change of numbering from MIM (mobile surface launched) to LIM (silo launched).
Since the missile was designed to intercept its targets in space, it did not need the large maneuvering fins of the A model.
Rather, it featured a third rocket stage with small control jets to allow it to maneuver in space.
Zeus B had a maximum range of 250 miles (400 km) and altitude of 200 miles (320 km).

Zeus A was designed to attack warheads through shock effects, like the Hercules, and was to be armed with a relatively small nuclear warhead.
As the range and altitude requirements grew, along with a better understanding of weapons effects at high altitude, the Zeus B was intended to attack its targets through the action of neutron heating.
This relied on the interceptor's warhead releasing a huge number of high energy neutrons (similar to the neutron bomb), some of which would hit the enemy warhead.
These would cause fission to occur in some of the warhead's own nuclear fuel, rapidly heating the "primary", hopefully enough to cause it to melt.
For this to work, the Zeus mounted the W50, a 400 kt enhanced radiation warhead, and had to maneuver within 1 km of the target warhead.
Against shielded targets, the warhead would be effective to as little as 800 feet (0.24 km).
The original Zeus A was similar to the original Hercules, but featured a revised control layout and gas puffers for maneuvering at high altitudes where the atmosphere was too thin for the aerodynamic surfaces to be effective. The Zeus B interceptor was longer at 14.7 metres (48 ft), 2.44 metres (8 ft 0 in) wide, and 0.91 metres (3 ft 0 in) in diameter. This was so much larger than the earlier Hercules that no attempt was made to have them fit into the existing Hercules/Ajax launchers. Instead, the B models were launched from silos, thus the change of numbering from MIM (mobile surface launched) to LIM (silo launched). Since the missile was designed to intercept its targets in space, it did not need the large maneuvering fins of the A model. Rather, it featured a third rocket stage with small control jets to allow it to maneuver in space. Zeus B had a maximum range of 250 miles (400 km) and altitude of 200 miles (320 km).
Zeus A was designed to attack warheads through shock effects, like the Hercules, and was to be armed with a relatively small nuclear warhead. As the range and altitude requirements grew, along with a better understanding of weapons effects at high altitude, the Zeus B was intended to attack its targets through the action of neutron heating. This relied on the interceptor's warhead releasing a huge number of high energy neutrons (similar to the neutron bomb), some of which would hit the enemy warhead. These would cause fission to occur in some of the warhead's own nuclear fuel, rapidly heating the "primary", hopefully enough to cause it to melt. For this to work, the Zeus mounted the W50, a 400 kt enhanced radiation warhead, and had to maneuver within 1 km of the target warhead. Against shielded targets, the warhead would be effective to as little as 800 feet (0.24 km).
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