Seals for gimbaling and/or fixed rocket engine nozzles, and associated systems and methods are disclosed. A representative rocket propulsion system includes a rocket engine having an exhaust nozzle, a seal plate carried by the exhaust nozzle, and a seal engaged with the seal plate. The seal includes at least one support, multiple pivotable first flaps, carried by the at least one support and positioned to contact the seal plate, and multiple pivotable second flaps, with an individual second flap positioned to shield a corresponding individual first flap. At least one forcing element is operatively coupled to at least one of the individual first flap or the individual second flap, to apply a pivoting force to the at least one of the individual first flap or the individual second flap.

Seals for gimbaling and/or fixed rocket engine nozzles, and associated systems and methods are disclosed. A representative rocket propulsion system includes a rocket engine having an exhaust nozzle, a seal plate carried by the exhaust nozzle, and a seal engaged with the seal plate. The seal includes at least one support, multiple pivotable first flaps, carried by the at least one support and positioned to contact the seal plate, and multiple pivotable second flaps, with an individual second flap positioned to shield a corresponding individual first flap. At least one forcing element is operatively coupled to at least one of the individual first flap or the individual second flap, to apply a pivoting force to the at least one of the individual first flap or the individual second flap.

A rocket motor comprises at least two propellant grains/grain segments; a case comprising the propellant grains/grain segments, stacked within the case; and a resin for substantially maintaining the grains/grain segments in position within the case. In another aspect, a rocket motor comprises at least two propellant grains/grain segments, each having an aft-end face and a fore-end face. At least two of the propellant grains/grain segments comprise a sleeve having propellant cast therein. The motor further comprises a case comprising the propellant grains/grain segments, stacked within the case, wherein the sleeve of one propellant grain/grain segment is coupled to the sleeve of an adjacent propellant grain/grain segment such that the fore-end face of one grain/grain segment is spaced from the aft-end face of an other grain/grain segment creating a gap therebetween. Methods for making the rocket motors are described.

A joint for mounting a component on a rocket, such as mounting a valve to a rocket body. The joint comprises a coiled roll pin and a shaft. The coiled roll pin comprises a rolled sheet defining an internal channel. The shaft extends through the internal channel and extends out both ends of the coiled roll pin. At each end of the shaft is disposed one or more compressible disc springs. Retaining rings or flat washers may compress the disc springs for axial restraint. The ends of the shaft may include a cover with an outer diameter larger than a joint hole. The joint compensates for vibrational loads, for example due to launch, and for dimensional changes, for example due to temperature gradients between two parts being connected by the joint. Some embodiments include no shaft, with the coiled roll pin axially secured by a cover or cover plate.

A joint for mounting a component on a rocket, such as mounting a valve to a rocket body. The joint comprises a coiled roll pin and a shaft. The coiled roll pin comprises a rolled sheet defining an internal channel. The shaft extends through the internal channel and extends out both ends of the coiled roll pin. At each end of the shaft is disposed one or more compressible disc springs. Retaining rings or flat washers may compress the disc springs for axial restraint. The ends of the shaft may include a cover with an outer diameter larger than a joint hole. The joint compensates for vibrational loads, for example due to launch, and for dimensional changes, for example due to temperature gradients between two parts being connected by the joint. Some embodiments include no shaft, with the coiled roll pin axially secured by a cover or cover plate.