Annotation: The pyrobolts, or explosive bolts, belong to the pyrotechnical devices with monolithic case consisting o f the cap, as a rule with hexagonal surface, and of cylindrical part with thread. The pyrobolts are separated into parts using the pyrotechnical charge placed inside the case. Owing to the simple design, reliability and short action time, the pyrobolts have found wide application in aerospace engineering for separation of assemblies and bays, in particular, stages, head modules, launching boosters, etc. So, for example, about 400 pyrobolts are used in the Proton launch vehicle. The designs of pyrobolts are markedly different. By method of explosive substance action on case structural elements, the pyrobolts are divided into two types: the pyrobolts using the shock wave formed at detonation of brisant explosive substance for case wall destruction and the pyrobolts using the pressure of gases arising at pyrotechnical charge blasting. By method of separation into parts, they are divided into fragmenting pyrobolts with ridge-cut, with piston, and shear pyrobolts. The paper deals with the design of various types of pyrobolts, their disadvantages are considered. The Yuzhnoye SDO-developed pyrobolt of shear type with segments is presented that uses radial shear forces of segments located in the hole of cylindrical part to separate the case parts. The above segments a re actuated using a rod with sealing rings and a piston connected to the rod through a rubber gasket; the piston moves under pressure of gases formed during pyro cartridge action. The following calculations are presen ted: strength analyses with determination of case load-carrying capacity; power analyses with justification of pyro cartridge selection for pyrobolt actuation. In the developed pyrobolt of shear type with segments, the case parts are separated without considerable shock loads and without high-temperature gases and fragments release into environment, ensuring reliable separation of bays and assemblies without damaging sensitive equipment.

Annotation: The paper deals with the issues that arise when solving the tasks connected with the possibility of suppressing the onboard radio electronic means of small-size unmanned aerial vehicles by focused powerful offfrequency emissions of microwave band electromagnetic fields.

Annotation: The analysis of medium- and high-resolution satellite images is made for the purpose of evaluating the impact of 2011-2015 drought on large freshwater basins of California. The considerable coast line shifts of Oroville and Folsom lakes were revealed.

Annotation: Service life (resource) of the device (system, structure, material) is one of the major factors, which defines the reliable performance of the device or necessity of its replacement. The purpose of this paper is to develop the engineering methodology to estimate the service life of the device to support the well-founded design decision-making. The methodology of estimation of the service life of material or structure is based on the generalization of great amount of Yuzhnoye SDO experimental data and theoretical research on the impact of various factors (properties of materials, loads, storage and operation conditions) on their service life on the ground of strength analysis. At the same time, service life definition is based on the results of stress and deformation analyses and their comparison with strength properties of the applied material (tensile strength and deformation properties). Strength properties of the material should be reduced to test conditions in terms of temperature, pressure, rate of loading, degrees of material aging etc. Methodology provides the estimation of safety margins in all phases of storage and operation of the device, consideration of the impact of the active factors (mass, temperature, loading, process of material aging), performance of calculations for the chosen specific zones of the device. It is shown that the service life estimation is in general case a probabilistic observation because of the random combination of the influencing factors (strength properties, storage and operation conditions, loads). Analysis of experimental and computation data as applied to solid-propellant rocket engine shows that the most dangerous zones, which define the service life, are the fuel charge channel (deformations at launch), a fuel-body coupling zone (breakaway coupling stress) and a “lock” zone of the release collar (concentration of shear and breakaway stresses and deformations). Developed methodological guidelines of the engineering estimate of the service life can be used as the computational basis for the service life of materials and structures in the phase of system design and updating of the assumed design solutions.

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.