The Corporal's
bulk, complexity, and slow rate of fire limited the
system's viability, and even before it went into service work had begun
on a successor. This materialized by 1955-56 as the Sperry M-29
(MGM-29) Sergeant, a physically-smaller weapon that could nonetheless
carry a warhead out to a range of 85 miles. Powered by a solid motor,
Sergeant was more mobile than Corporal, although it was transported in
a semi-knocked down condition with the warhead separate from the rest
of the airframe. The solid propellant obviated any need for time
consuming fueling procedures, and although Sergeant was not instantly
ready for launch, the countdown was greatly compressed when compared to
that of the Corporal. Sergeant's purely inertial guidance system also
cut down on the amount of ground support equipment, as well as making
the in-flight missiles invulnerable to ECM.
Sergeants were in service with US units in South Korea into the late
1970s, but in April 1977 it was announced that the missiles were being
withdrawn as part of a drawdown of American forces in the theater.
Several years earlier, the system had been retired from use in Europe.
Sergeant components remain in use today as parts of target vehicles;
the Starbird targets for Army ERINT tests were made up of a
Sergeant-derived second stage above a Talos booster, while the Orbital
Sciences Storm targets for THAAD testing used Sergeant as a first
stage, topped by a former Minuteman
third stage. Sergeant-derived stages have been used in many
experimental rockets over the years, including the Strypi vehicle used
to launch a W50 nuclear warhead during the Dominic Checkmate
atmospheric nuclear test.