Piezoelectric actuators and motors are increasingly essential for space applications due to their precision, compactness, and efficiency. This review explores their advantages over traditional actuators, emphasizing their minimal electromagnetic interference, high responsiveness, and operational reliability in harsh space environments. This study highlights the challenges posed by space conditions such as vacuum, microgravity, extreme temperatures, and radiation, which require robust design and material considerations. A comprehensive review of missions using piezo actuators, including their operating principles, material advancements, and innovative designs tailored for space conditions. In addition, numerical calculations were performed by COMSOL Multiphysics 5.6 software with the aim of analyzing the impact of temperature variations typical of the low Earth orbit (LEO) on the electromechanical properties of the piezoelectric transducer. The results indicate significant variations in the characteristics of the resonant frequency, impedance, and phase frequency in a temperature range from −20 °C to 40 °C, emphasizing the importance of accounting for thermal effects in the design. The calculations show that advantages which are proposed by piezoelectric motion systems must be combined with adaptability to harsh environmental conditions and call for further research to enhance their robustness and performance for broader application in future space missions.

This paper presents the design, development, and investigation of a novel piezoelectric inertial motor whose target application is the low Earth orbit (LEO) temperature conditions. The motor utilizes the inertial stick–slip principle, driven by the first bending mode of three piezoelectric bimorph plates, and is compact and lightweight, with a total volume of 443 cm³ and a mass of 28.14 g. Numerical simulations and experimental investigations were conducted to assess the mechanical and electromechanical performance of the motor in a temperature range from −20 °C to 40 °C. The results show that the motor’s resonant frequency decreases from 12,810 Hz at −20 °C to 12,640 Hz at 40 °C, with a total deviation of 170 Hz. The displacement amplitude increased from 12.61 μm to 13.31 μm across the same temperature range, indicating an improved mechanical response at higher temperatures. The motor achieved a maximum angular speed up to 1200 RPM and a stall torque of 13.1 N·mm at an excitation voltage amplitude of 180 V_p-p. The simple and scalable design, combined with its stability under varying temperature conditions, makes it well suited for small satellite applications, particularly in precision positioning tasks such as satellite orientation and free-space optical (FSO) communications.

Analyzing the research directions of leading aviation companies, it is evident that biocomponents will soon become a very important addition to the fuel used in turbine aircraft engines. Similarly, intensive efforts are underway to implement this type of solution in the armed forces. Here, the situation is more complex. All military fuels are intended for long-term storage, and bio-additives significantly alter the properties of fuels during this specific storage process. These changes invariably result in the deterioration of fuel quality parameters. The article presents an analysis and conclusions related to biocomponents as additives to F-35 fuel (NATO code-the military equivalent of Jet A-1 fuel). F-35 aviation fuel mixtures with the addition of biocomponents (HVO-Hydrorefined Vegetable Oil) at concentrations of 0–20% (V/V) were independently composed and stored for extended periods (0–6 months). The disadvantages and potential problems of this solution are discussed. The research has demonstrated that using biocomponents in the mixtures significantly alters the course of the distillation curve and increases the fuel’s electrical conductivity. Another adverse effect observed was a significant deterioration in the fuel’s low-temperature properties. The research indicates that using a bio-additive like HVO in F-35 fuel will require addressing many challenges. At the level of laboratory tests, it is to determine the limit value of the share of a biocomponent in a mixture at which the normative values are not yet violated and to confirm or rule out whether the mixtures are suitable for long-term storage.

This paper presents the design, numerical analysis, and experimental investigation of a compact traveling-wave piezoelectric motor for continuous and incremental angular motion. The key advancement of the proposed design is a compact coaxial direct-drive architecture that combines a single ring-shaped piezoelectric stator with four independently excited electrode sections, three discrete spherical contact elements, a cone-shaped rotor, and an adjustable spring-based preload mechanism. In contrast to conventional traveling-wave motors employing continuous annular or toothed contact interfaces, the proposed configuration localizes the stator–rotor interaction at three predefined contact points while allowing both continuous bidirectional rotation and incremental angular positioning within the same actuator. Numerical analysis identified the operating mode at 39.95 kHz and confirmed the formation of elliptical displacement trajectories at the spherical contact elements. The calculated resonance frequency and effective electromechanical coupling coefficient were 39.93 kHz and 4.36%, respectively. Experimental measurements showed resonance of 39.94 kHz with an effective coupling coefficient of 4.47%. The motor achieved a maximum rotational speed of 87 ± 2.2 RPM at 180 V_p-p. The maximum stall torque reached approximately 8.3 N·mm and 8.4 N·mm for clockwise (CW) and counterclockwise (CCW), respectively, at 180 V_p-p. Depending on the excitation amplitude, the angular step varied from 0.082 ± 0.015° to 3.038 ± 0.120°. The results confirm that the proposed compact motor can provide controllable continuous rotation and incremental angular positioning.

This study presents numerical and experimental investigations of a voltage-controlled active preload adjustment system for an ultrasonic traveling wave piezoelectric motor intended for potential use in space-related systems. The proposed preload system consists of two ring-shaped piezoceramic elements driven by a DC voltage of up to 300 V_DC. The passive conical spring provides the nominal rotor preload, while the piezoelectric ring stack enables open-loop remote fine adjustment of the stator–rotor contact force by modifying the axial compression of the spring. Finite element simulations were performed over a temperature range from −25 °C to 55 °C to evaluate the electromechanical response and thermal sensitivity of the preload system. The numerical results indicated that the active preload system can generate a simulated preload force variation of approximately 0.47 N at 300 V_DC, corresponding to approximately 21.4% of the nominal initial preload force of 2.2 N. Experimental tests were conducted in a thermal vacuum chamber at a pressure of 5.6 × 10⁻⁶ mbar. The measured displacement of the piezoceramic preload stack ranged from 0.33 µm to 2.36 µm and showed good agreement with the numerical displacement results. Motor speed measurements demonstrated that increasing the preload-control voltage from 0 to 300 V_DC resulted in an average angular speed increase of approximately 17–20 RPM, depending on temperature. The results demonstrate that the proposed system can provide compact open-loop preload fine adjustment under thermal vacuum conditions, with preload force variation supported by FEM estimation and experimentally validated displacement response.

Piezoelectric unimorph actuators are promising candidates for precision actuation systems in small satellites, where their electromechanical performance must remain predictable under vacuum and temperature variations. However, actuator performance is determined not only by the piezoelectric material but also by the passive layer and bonding interface, whose combined influence under thermal-vacuum conditions requires systematic evaluation. This study presents a numerical and experimental investigation of the temperature-dependent electromechanical characteristics of piezoelectric unimorph actuators incorporating PIC 181 piezoceramic plates, passive layers made of 7075-T6 aluminum or Ti-6Al-4V titanium, and three different vacuum-compatible bonding materials. Numerical analyses were performed to determine modal, impedance–frequency, and displacement–frequency characteristics over the temperature range of 253.15–323.15 K, while experimental investigations under vacuum conditions quantified the additional influence of the bonding interface. Increasing temperature caused a decrease in resonance frequency for both passive-layer configurations. Actuators with Ti-6Al-4V passive layers generally exhibited higher resonance frequencies, lower impedance values, and larger displacement amplitudes than those with 7075-T6 aluminum passive layers. The maximum measured displacement amplitudes reached 23.11 µm for the aluminum-based actuator and 29.67 µm for the titanium-based actuator at 323.15 K. Among the investigated bonding materials, BM No. 3 consistently provided the lowest impedance and highest displacement response. The results demonstrate that passive-layer and bonding-material selection should be considered jointly and identify the Ti-6Al-4V/BM No. 3 combination as the most favorable among the investigated configurations for resonant piezoelectric unimorph actuation under the tested thermal-vacuum conditions.