Annotation: Separation of the spent LV stages is one of the important problems of the rocket technology, which requires the comprehensive analysis of different types of systems, evaluation of their parameters and structural layouts. Basic requirements are specified that need to be taken into account when engineering the separation system: reliable and safe separation, minimal losses in payload capability, keeping sufficient distance between the stages at the moment of the propulsion system start. Detailed classification of their types («cold», «warm», «hot», «cold-launched» separation) is given and their technical substance with advantages and drawbacks is described. Certain types of «cold» and «warm» separation of the spent stages of such rockets as Dnepr, Zenit, Antares, Falcon-9 with different operating principle are introduced – braking with the spent stage and pushing apart two stages. Brief characteristics of these systems are given, based on the gas-reactive nozzle thrust, braking with solid-propellant rocket engines, separating with spring or pneumatic pushers. Development of the separation system for the advanced Cyclone-4M ILV is taken as an example and design sequence of stage separation is suggested: determination of the necessary separation velocity and capability of the separation units, determination of the number of active units, calculation of design and energy parameters of the separation units, analysis of the obtained results followed by the selection of the separation system. Use of empirical dependences is shown, based on the great scope of experimental and theoretical activities in the process of design, functional testing and flight operation of similar systems in such rockets as Cyclone, Dnepr and Zenit. According to the comparative analysis results, pneumatic separation system to separate Cyclone-4M Stages 1 and 2 was selected as the most effective one. Its basic characteristics, composition, overall view and configuration are specified. Stated materials are of methodological nature and can be used to engineer the separation systems for LV stages, payload fairings, spacecraft etc.

Annotation: Some main results of scientific support of development of launch vehicle head module composite loadbearing bays are presented. The methodology is proposed for developing these units. By the example of payload fairing and interstage bay of Cyclone-4 launch vehicle, high efficiency is shown of proposed methodology implementation when selecting their rational design and technological parameters.

Annotation: Explosive bolts are widely used as actuating devices in the spacecraft separation systems. Explosive bolt body is divided into parts as a result of engagement of the pyromixture placed inside. Activated explosive bolts have negative mechanical effect on the interface elements and sensitive electronic devices installed nearby owing to explosive behavior of the pyromixture combustion, generating shock front with high pressure and velocities, impacts and collisions of the structural units. Cumulative effect of the above factors on the separated objects is called pyroshock. For separation systems with increased requirements to external actions and cleanliness, authors developed a shear explosive bolt or pyrobolt, divided into parts, cutting the body walls in segments, which are set in motion by action of the pressure of gases, released as a result of pyrocartridge activation. The basic sources of pyroshock for these shear explosive bolts with segments are: combustion of pyromixture, internal impacts of structural units against the bolt body; cutting of body wall in segments, release of preliminary deformed interface after activation. Structural solutions are presented to reduce the pyroshock per each of the components. Vibration impulsive loading during pyromixture combustion is reduced by optimization of explosive quantity, finding its minimum to provide the reliable activation of the device. To reduce the impact on the explosive bolt elements and shock front interface the rubber gasket is installed in the path of shock wave distribution, partially disseminating and absorbing its kinetic energy. Damper, made of easily deformable aluminum alloy, is also installed to decrease the internal impact of the rod against the explosive bolt body. Functional testing of the device, using the pendulum suspension and measuring separation speed and vibration impulsive loading, showed that body parts of the shear explosive bolt with segments are separated without significant impact loads and discharge of high-temperature gases and debris, providing reliable separation of compartments and units without damaging the sensitive equipment. Obtained values of the mechanical momentum, I = 0,4÷0,7 N•s and shock load spectrum – g-load 1950 g at the frequency range up to 5000 Hz, meet the up-to-date requirements to pyrotechnical devices.