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18 pages, 5108 KiB

Open AccessArticle

Design and Analysis of a Micro–Electro-Mechanical System Thruster for Small Satellites and Low-Thrust Propulsion

by Yubin Zhong, Fabrizio Ponti, Francesco Barato, Guojun Xia, Siyu Li, Xiao Zhang and Tao Wu

Aerospace 2025, 12(3), 172; https://doi.org/10.3390/aerospace12030172 - 21 Feb 2025

Viewed by 2341

Abstract

As a cost-effective and versatile solution, small satellites are increasingly being considered for space exploration. However, one of the major challenges in deploying small satellites for high total impulse missions, particularly deep space exploration, lies in the propulsion system. These missions face strict constraints in terms of volume, mass, and power budgets. This paper proposes a potential solution to this issue through the design of a bipropellant MEMS thruster. Simulation results indicate that this type of thruster offers superior performance compared to the monopropellant propulsion systems typically used in small satellite missions. Specifically, the bipropellant MEMS thruster demonstrates enhanced specific impulse and thrust-to-weight ratio, making it a promising alternative for small satellite propulsion in high total impulse missions. Full article

(This article belongs to the Special Issue Deep Space Exploration)

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17 pages, 9827 KiB

Open AccessArticle

Leading-Edge Vortex Lift (LEVL) Sample Probe for Venusian Atmosphere

by Christopher Isaac and Nick Jones

Aerospace 2022, 9(9), 471; https://doi.org/10.3390/aerospace9090471 - 23 Aug 2022

Cited by 2 | Viewed by 2350

Abstract

Can a small, lightweight, free-falling sample probe be slowed enough in the Venusian atmosphere to run a 10 min microelectromechanical systems (MEMS) ion gas micro spectrometer, without adding a propulsion systems or explosives and parachutes to the probe mass? To meet this requirement a leading-edge vortex lift (LEVL) autorotating probe design (i.e., maple or sycamore seed shape) has been proposed and evaluated. It has been found that a probe with a total mass of less than 1 kg would allow prolonged flight longer than 15 min. Mathematical modelling and physical scale model testing has been performed to show that this flight time is achievable, allowing MEMS ion gas micro-spectrometer sampling of the Venusian atmosphere. Full article

(This article belongs to the Special Issue The Search for Signs of Life on Venus: Science Objectives and Mission Designs)

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18 pages, 6994 KiB

Open AccessFeature PaperReview

MEMS Vaporazing Liquid Microthruster: A Comprehensive Review

by Donato Fontanarosa, Luca Francioso, Maria Grazia De Giorgi and Maria Rosaria Vetrano

Appl. Sci. 2021, 11(19), 8954; https://doi.org/10.3390/app11198954 - 26 Sep 2021

Cited by 9 | Viewed by 3391

Abstract

The interest in developing efficient nano and pico-satellites has grown in the last 20 years. Secondary propulsion systems capable of serving specific maneuvers are an essential part of these small satellites. In particular, Micro-Electro-Mechanical Systems (MEMS) Vaporizing Liquid Microthrusters (VLM), using water as a propellant, represent today a smart choice in terms of simplicity and cost. In this paper, we first propose a review of the international literature focused on MEMS VLM development, reviewing the different geometries and heating solutions proposed in the literature. Then, we focus on a critical aspect of these micro thrusters: the presence of unstable phenomena. In particular, the boiling instabilities and reverse channel flow substantially impact the MEMS VLMs’ performance and limit their applicability. Finally, we review the research focused on the passive and active control of the boiling instabilities, based on VLM geometry optimization and active heating strategies, respectively. Today, these ones represent the two principal research axes followed by the scientific community to mitigate the drawbacks linked to the use of MEMS VLMs. Full article

(This article belongs to the Special Issue Micro Power Technologies for Air and Space Vehicles)

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12 pages, 544 KiB

Open AccessArticle

Factors Associated with Callus Formation in the Plantar Region through Gait Measurement in Patients with Diabetic Neuropathy: An Observational Case-Control Study

by Ayumi Amemiya, Hiroshi Noguchi, Makoto Oe, Kimie Takehara, Yumiko Ohashi, Ryo Suzuki, Toshimasa Yamauchi, Takashi Kadowaki, Hiromi Sanada and Taketoshi Mori

Sensors 2020, 20(17), 4863; https://doi.org/10.3390/s20174863 - 28 Aug 2020

Cited by 8 | Viewed by 6071

Abstract

Callus has been identified as a risk factor leading to severe diabetic foot ulcer; thus, it is necessary to prevent its formation. Callus formation under the first, second, and fifth metatarsal heads (MTHs) is associated with external forces (pressure and shear stress) during walking. However, the gait factors increasing the external forces remain undetermined. Thus, this study aims to identify the factors increasing the external forces to prevent callus formation. In 59 patients with diabetic neuropathy wearing their usual shoes, the external forces, and the lower extremity joint angles were measured using MEMS force sensors and motion sensors. The external forces and their relationship with the lower extremity joint angles and footwear size were determined. Risk factors causing high external forces on the first MTH included small flexion of the knee joint (p = 0.015) and large ankle pronation motion (p = 0.034) to obtain propulsion. For the second MTH, wearing excessively long footwear was identified (p = 0.026). For the fifth MTH, high external force was related to tight width footwear (p = 0.005). An effective intervention for preventing callus formation for the first MTH would involve assisting the push-off foot motion using rocker-sole footwear or gait training. For the second and fifth MTHs, wearing appropriate size footwear would be effective. Full article

(This article belongs to the Special Issue Wearable Inertial Sensors)

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11 pages, 2740 KiB

Open AccessArticle

Controllable Electrically Guided Nano-Al/MoO₃ Energetic-Film Formation on a Semiconductor Bridge with High Reactivity and Combustion Performance

by Xiaogang Guo, Qi Sun, Taotao Liang and A. S. Giwa

Nanomaterials 2020, 10(5), 955; https://doi.org/10.3390/nano10050955 - 18 May 2020

Cited by 7 | Viewed by 2885

Abstract

Film-forming techniques and the control of heat release in micro-energetic chips or devices create challenges and bottlenecks for the utilization of energy. In this study, promising nano-Al/MoO₃ metastable intermolecular composite (MIC) chips with an uniform distribution of particles were firstly designed via a convenient and high-efficiency electrophoretic deposition (EPD) technique at room temperature and under ambient pressure conditions. The mixture of isopropanol, polyethyleneimine, and benzoic acid proved to be an optimized dispersing agent for EPD. The kinetics of EPD for oxidants (Al) and reductants (MoO₃) were systematically investigated, which contributed to adjusting the equivalence ratio of targeted energetic chips after changing the EPD dynamic behaviors of Al and MoO₃ in suspension. In addition, the obtained nano-Al/MoO₃ MIC energetic chips showed excellent heat-release performance with a high heat release of ca. 3340 J/g, and were successfully ignited with a dazzling flame recorded by a high-speed camera. Moreover, the fabrication method here is fully compatible with a micro-electromechanical system (MEMS), which suggests promising potential in designing and developing other MIC energetic chips or devices for micro-ignition/propulsion applications. Full article

(This article belongs to the Special Issue Nanoenergetic Materials: Preparation, Properties, and Applications)

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42 pages, 17294 KiB

Open AccessReview

Recent Advances in MEMS-Based Microthrusters

by Bendong Liu, Xinrui Li, Jiahui Yang and Guohua Gao

Micromachines 2019, 10(12), 818; https://doi.org/10.3390/mi10120818 - 26 Nov 2019

Cited by 21 | Viewed by 8015

Abstract

With the development of micro/nano satellites and formation flying, more advanced spatial propulsion technology is required. In this paper, a review of microthrusters developments that based on micro electromechanical systems (MEMS) technology adopted in microthrusters is summarized. The microthrusters in previous research are classified and summarized according to the types of propellants and the working principles they utilized. The structure and the performance including the thrust, the impulse and the specific impulse of various microthrusters are compared. In addition, the advantages and the disadvantages of these microthrusters presented in the paper are discussed. Full article

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11 pages, 1730 KiB

Open AccessArticle

A Literature Review Informing an Operational Guideline for Inertial Sensor Propulsion Measurement in Wheelchair Court Sports

by Jonathan B. Shepherd, Daniel A. James, Hugo G. Espinosa, David V. Thiel and David D. Rowlands

Sports 2018, 6(2), 34; https://doi.org/10.3390/sports6020034 - 13 Apr 2018

Cited by 19 | Viewed by 5753

Abstract

With the increasing rise of professionalism in sport, teams and coaches are looking to technology to monitor performance in both games and training to find a competitive advantage. Wheelchair court sports (wheelchair rugby, wheelchair tennis, and wheelchair basketball) are no exception, and the use of microelectromechanical systems (MEMS)-based inertial measurement unit (IMU) within this domain is one innovation researchers have employed to monitor aspects of performance. A systematic literature review was conducted which, after the exclusion criteria was applied, comprised of 16 records. These records highlighted the efficacy of IMUs in terms of device validity and accuracy. IMUs are ubiquitous, low-cost, and non-invasive. The implementation in terms of algorithms and hardware choices was evidenced as a barrier to widespread adoption. This paper, through the information collected from the systematic review, proposes a set of implementation guidelines for using IMUs for wheelchair data capture. These guidelines, through the use of flow-charts and data tables, will aid researchers in reducing the barriers to IMU implementation for propulsion assessment. Full article

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