Pros and cons. (What's Up).

Cast composite propellants can be very closely compared with two-component glues found on the market. After careful mixing, the slur is then poured into the body of the motor section of the missile and then cured. Their advantage is a very high energy content, but the down side is a higher heat signature. Cast composite is used, for instance, as the propellant of the Aster missile booster stage.

Double-based propellants are so called because their two main components are nitro-glycerine and nitro-cellulose. Both cast and extruded types offer similar specific impulses. The extruded variant is a homogeneous paste that is given its definitive shape as it comes out of the press. It then has to be 'bodied'. One technique in this instance is filament (typically Kevlar) winding (see title picture).

The cast variation on the double-base theme first starts life as a hair-thin spaghetti, which is then cut into minute sections resulting in something of the consistency of a coarse sand. This is mixed with a binding solution and then poured into the missile body. This method can be seen as an advantage in terms of shape flexibility, but is more labour intensive.