The reentry or terminal phase starts when the missile is at an altitude of 62 miles (100 km), during which it has a speed of over four miles (7 km) a second and it deploys its warhead. ICBM designs allow them to deploy conventional, biological, as well as chemical warheads. However, none of them have been deployed so far.
The Minuteman III
The Minuteman III is the only land-based ICBM in the U.S. arsenal of nuclear weapons. Development of the ICBM began in the 1950s, and the first Minuteman entered service in 1962 with the capability to strike Soviet cities. The upgraded version, Minuteman II, added range, accuracy, and penetration aids to help beat the anti-ballistic missile system of adversaries.
The Minuteman III was deployed in 1970 and offered a superior ICBM package to the U.S. Air Force. The almost 60-feet (18.3 m) tall missile has an operational range of 8,700 miles (14,000 km) with an accuracy of about 800 feet (240 m). It was also the first Minuteman missile to feature multiple independently targetable reentry vehicles (MIRVs), which basically meant that a single missile could target three locations during its flight.
The ICBM uses an inertial navigation system to make its way to its target and can cruise at Mach 23.