One of the main differences between manned aircraft and missiles is that in the former the “short period” dynamic characteristics should usually be at least moderately stable, while in the latter considerable instability can be tolerated.

However, this requires that the missile control system should have high gain “synthetic” feedback. Consequently, problems of stability associated with high gain are introduced, which do not occur with such severity in the manned aircraft. Typical missile stability problems of this kind, such as those arising from structural flexibility and propellant sloshing, are discussed.

Ballistic missiles, because they are required to operate in conditions where aerodynamic forces are sometimes negligible, need to utilise non-aerodynamic control forces. This introduces special problems, which have a parallel only in VTOL aircraft. The long duration attitude control of satellites in the presence of very small disturbances also presents a problem not encountered in the aircraft field.

The uncertainty of human pilot response is discussed in relation to the difficulties of adequate aircraft control system simulation. Some remarks are also made on the interaction between control about various axes. These interactions are often fundamentally different between aircraft and missiles.