Aluminum–carbon nanotube (Al–CNT) composites represent a cutting-edge class of materials characterized by their exceptional mechanical, thermal, and electrical properties, making them highly promising for aerospace, automotive, electronics, and energy applications. This review systematically examines the impact of various fabrication methods, including conventional powder metallurgy, diffusion and reaction coupling, as well as adhesive and reaction bonding on the microstructure and performance of Al–CNT composites. The analysis emphasizes the critical role of CNT dispersion, interfacial bonding, and the formation of reinforcing phases, such as Al₄C₃ and Al₂O₃, in determining the mechanical strength, wear resistance, corrosion resistance, and thermal stability of these materials. The challenges of CNT agglomeration, high production costs, and difficulties in controlling interfacial interactions are highlighted alongside potential solutions, such as surface modifications and reinforcement strategies. The insights presented aim to guide future research and innovation in this rapidly evolving field.

Elastomeric ablative coatings are essential for protecting solid rocket motor (SRM) combustion chambers from extreme thermal and erosive environments, and their performance is governed by both material composition and processing strategy. This review examines the main elastomer systems used for SRM insulation, including ethylene propylene diene monomer (EPDM), nitrile butadiene rubber (NBR), hydroxyl-terminated polybutadiene (HTPB), polyurethane (PU), silicone-based compounds, and related hybrids, and discusses how their rheological behavior, cure kinetics, thermal stability, and ablation mechanisms affect manufacturability and in-service performance. A comprehensive assessment of coating technologies is presented, covering casting, molding, centrifugal forming, spraying, automated deposition, and emerging additive-manufacturing approaches for complex geometries. Emphasis is placed on processing parameters that control adhesion to metallic substrates, layer uniformity, defect formation, and thermomechanical integrity under high-heat-flux exposure. The review integrates current knowledge on how material choice, surface preparation, and application sequence collectively determine insulation efficiency under operational SRM conditions. Practical aspects such as scalability, compatibility with complex chamber architectures, and integration with quality-control tools are highlighted. By comparing the capabilities and limitations of different materials and technologies, the study identifies key development trends and outlines remaining challenges for improving the durability, structural robustness, and ablation resistance of next-generation elastomeric coatings for SRMs.

This study investigates the impact of nickel doping on the thermal and combustion properties of ammonium perchlorate/carboxymethyl cellulose (AP/CMC) composites. Through comprehensive SEM-EDS, FTIR, XRD, DSC, TGA, and burning rate analyses, significant improvements in the structural and functional characteristics of the AP/CMC-Ni composite were observed compared to those of pure AP and AP/CMC composites. The SEM-EDS analysis revealed that nickel incorporation resulted in thicker and more irregular CMC fibers, indicating substantial morphological changes. The FTIR spectroscopy showed shifts in the O-H and C=O stretching bands, pointing to interactions between nickel ions and CMC functional groups. The XRD patterns highlighted a decrease in crystallinity and the presence of NiO phases, confirming the successful integration of nickel into the CMC matrix. The thermal analysis demonstrated that nickel doping significantly lowered the decomposition temperature of the AP/CMC composite, as evidenced by DSC, and enhances the thermal degradation process, as shown by TGA. The AP/CMC-Ni composite exhibited a higher burning rate across all of the tested pressures, highlighting the catalytic effect of nickel in improving the combustion efficiency. The burning rate for AP/CMC follows the power-law expression with constants a = 2.34 and n = 0.499, while for AP/CMC-Ni, the constants are a = 3.35 and n = 0.475. This study highlights the essential role of nickel doping in facilitating the decomposition of AP within the AP/CMC composite. By lowering the decomposition temperature, nickel enhances the overall combustion process, making the AP/CMC-Ni composite more efficient for applications requiring controlled thermal decomposition. These findings provide valuable insights for the design and development of high-performance composite materials in advanced industrial applications.

Gimbaled thrust vector control (TVC) systems are widely employed in modern launch vehicles to provide attitude control during powered flight. However, the aerodynamic influence of the circumferential geometric discontinuity introduced by the gimbal joint gap on nozzle internal and external flow remains insufficiently studied in open literature. The purpose of this study is to evaluate aerodynamic losses and flow field modifications of bell-shaped rocket nozzles with the presence of a gimbal joint gap using computational fluid dynamics (CFD) simulation. These calculations were done using the Reynolds-Averaged Navier–Stokes (RANS) model in 2D axisymmetric flow in ANSYS Fluent software. For modelling the flow properties in compressible separated flows, the k-ω SST turbulence model was selected. Two nozzle configurations, with and without the gap of the gimbal joint, were compared. The Sutherland viscosity law and the NASA polynomial thermodynamic data were used for the working fluid and it was modeled as an ideal compressible gas representative of the combustion products of LOX/Kerosene. The exit to throat area expansion ratio for nozzle geometry is 8.97, which means that the nozzle is designed to have a supersonic exit condition. The CFD results showed a good agreement with the theoretical results, showing the validity of the numerical approach. The nozzle studied here operates under overexpanded conditions at sea level, where the nozzle exit static pressure falls below ambient pressure, giving rise to oblique shock waves in the exhaust plume and making the accurate characterisation of flow disturbances particularly important. The presence of the gimbal joint gap was found to introduce aerodynamic losses in Mach number of 6.74%, providing quantitative design-relevant data for gimbaled nozzle systems in launch vehicles.Keywords: gimbal joint gap, bell nozzle, TVC, CFD.

This article is devoted to a review of existing small upper stages, including perspective upper stages under development or testing, actively used in the tasks of launching small spacecraft into target orbit, the relevance of which has recently been increasing against the background of the trend of miniaturization of spacecraft and, consequently, the reduction of payload mass. The paper considers the main classification features of upper stages, including mass, type of propulsion system, design and layout schemes. In particular, the advantages and disadvantages of the above schemes are discussed in terms of layout flexibility, design weight, manufacturability, ease of assembly, and operational reliability. A comparative analysis between them is given for such key parameters as thrust developed by the propulsion system, the mass of the payload to be launched to the target orbit, and the method of propellant supply. The peculiarities of the use of single-component and two-component fuel are also considered, as well as the influence of fuel pair selection on the efficiency and safety of the upper stage. The purpose of this study is to select and justify a scheme for the realization of a small upper stage combining optimal technical characteristics, high reliability, economic efficiency and environmental safety. The key element of scientific novelty is the application of a multi-criteria analysis method to evaluate various designs for small upper stages. This method allows formalizing and balancing conflicting engineering criteria, including mass efficiency, specific impulse, multiple firing capability, technological maturity, etc.

Pintle injectors offer variable thrust capability and combustion stability advantages for liquid rocket engines. This study presents experimental and numerical investigation of spray characteristics for a liquid–liquid pintle injector using water as simulant. Ten cold flow tests covering total momentum ratio (TMR) from 0.36 to 2.76 captured spray angle variations from 26° to 80°. Computational fluid dynamics (CFD) simulations using Ansys Fluent 2025 R1 with the Volume of Fluid method and dispersed interface modeling showed good agreement with experimental spray angles for TMR > 0.74 (error < 8%), but demonstrated increasing discrepancy at lower TMR values (up to 62% error at TMR = 0.36). This deviation indicates limitations of steady-state RANS models in capturing unsteady, fuel-dominated flow regimes. The experimental dataset provides validation benchmarks for CFD modeling and contributes to injector design optimization for sounding rocket applications.