Type Of Propulsion Research Articles

Advanced Air Mobility: Opportunities and Challenges Deploying eVTOLs for Air Ambulance Service

Advanced air mobility (AAM) is a broad concept enabling consumers access to on-demand air mobility, cargo and package delivery, healthcare applications, and emergency services through an integrated and connected multimodal transportation network. While a number of technical and social concerns have been raised about AAM, early use cases for emergency response and aeromedical transport may be key to demonstrating the concept and building public acceptance. Using a five-step multi-method approach consisting of preliminary scoping, modeling performance metrics, developing baseline assumptions, analyzing scenarios, and applying a Monte Carlo sensitivity analysis, this study examines the potential operational and market viability of the air ambulance market using a variety of aircraft and propulsion types. The analysis concludes that electric vertical take-off and land (eVTOL) aircraft could confront a number of operational and economic challenges for aeromedical applications compared to hybrid vertical take-off and land (VTOL) aircraft and rotorcraft. The study finds that technological improvements such as reduced charge times, increased operational range, and battery swapping could make the eVTOL aircraft more reliable and cost-effective for aeromedical transport.

Research of current distribution by phases in asynchronous electric motor with a combined winding

THE PURPOSE. Consider the use of propeller electric installations as part of ship electrical complexes with a single electric power system. Highlight the rudder drives as a special type of electric propulsion of ships in northern latitudes. Investigate unified electric power systems with a propeller electric installation for the existence of power exchange oscillations in them. Propose methods and means for eliminating power oscillations in such systems.METHODS. To carry out the research, a single electric power system with electric rudder propellers of the world's only asymmetric icebreaker Baltika was considered. All the main elements of such system have been analyzed in detail. Experimental studies were carried out aimed at studying the operating modes of a unified electric power system.RESULTS. Experimental oscillograms of currents of parallel operating diesel-generator sets in different modes have been obtained. The existence of exchange and in-phase power oscillations during the operation of the unified electric power system of the icebreaker "Baltika" is noted. The data on the negative influence of power oscillations on the operation of the electrical complex of the icebreaker are presented.CONCLUSION. The use of ice-class sea vessels is an extremely important task for the Russian Federation. The installation of blocks that eliminate exchange and in-phase power oscillations will improve the reliability and efficiency of the use of marine vessels with electric rudder propellers when servicing hydrocarbon production on the Arctic shelf.

Eco-Friendly Tourism Decision Making during COVID-19—Sailing Tourism Example

In 2020, tourism was highly affected by COVID-19 and its restrictions, such as tourist traffic. Decisions related to trips were made in a state of high risk and uncertainty. This article’s main aim is to present the results of research on decision making by people practising sailing tourism during COVID-19. The survey was conducted in the first quarter of 2021 on 580 sailors from Poland, Germany, Croatia, Italy, France, and Turkey. This is interesting because of the specificity of this form of nautical tourism, which is characterised by high flexibility in the planning and implementation of the cruise. Sailing tourism is also environmentally friendly due to the type of propulsion used and the low noise levels generated. Research has shown that country-specific travel restrictions impact sailing tourism and cruise decisions. The obtained results are important for developing sailing tourism and may contribute to rationalising decisions taken during crises.

Modeling the Effects of Implementation of Alternative Ways of Vehicle Powering

The trend to replace traditional fossil fuel vehicles is becoming increasingly apparent. The replacement concerns the use of pure biofuels or in blends with traditional fuels, the use of hydrogen as an alternative fuel and, above all, the introduction of electric propulsion. The introduction of new types of vehicle propulsion affects the demand for specific fuels, the needs for new infrastructure, or the nature of the emissions to the environment generated by fuel production and vehicle operation. The article presents a mathematical model using the difference of two logistic functions, the first of which describes the development of the production of a specific type of vehicle, and the second, the withdrawal of this type of vehicle from traffic after its use. The model makes it possible to forecast both the number of vehicles of each generation as a function of time, as well as changes in energy demand from various sources and changes in exhaust emissions. The results of the numerical simulation show replacing classic vehicles with alternative vehicles increases the total energy demand if the generation of the next generation occurs earlier than the decay of the previous generation of vehicles and may decrease in the case of overlapping or delays in the creation of new vehicles compared to the course of the decay function of the previous generation. For electric vehicles, carbon dioxide emissions are largely dependent on the emissions from electricity generation. The proposed model can be used to forecast technology development variants, as well as analyze the current situation based on the approximation of real data from Vehicle Registration Offices.

A task-based analysis of the economic viability of low-manned and unmanned cargo ship concepts

While successful trials for autonomously navigating ships have been conducted, commercially available unmanned cargo ships are currently unavailable. However, there are many solutions available that will allow for low-manned ship concepts long before fully unmanned ships are possible. There are many drivers for low-manned and unmanned shipping, ranging from availability of workforce, to increased safety to economic. This article investigates the economic viability of several low-manned ship concepts as well as the unmanned ship concept for a short sea container vessel. The operating cost of these concepts are compared to those of a conventional vessel. That way, an assessment can be made on the economic viability. The results show that the low-manned concepts investigated in this article are worthwhile for the ship owner, as some savings can be achieved. The economic viability of the unmanned concept is dependent on the chosen type of propulsion.

Comprehensive spatial and cost assessment of urban transport options in Munich

The constant introduction of new mobility options in urban transportation complexifies the mode choice of individual users. Relevant indicators have to give users a reliable guideline for mode choice as well as giving municipalities and industry a reasonable guideline for strategic orientation. Therefore, in this paper, a comprehensive assessment of transport options is conducted for indicators such as travel time, costs, CO2 emissions and external costs. The main added value of this paper is the method employed: Trips with origin-destination (OD) coordinates are routed for different transport modes using Open Trip Planner (OTP). In the next step, a cost model calculates these indicators for all transport modes. The presented method can compare privately-owned vehicles with different propulsion types with conventional as well as new public mobility services from a spatial perspective within the Munich area as a case study. The comprehensive information provided by these results helps mobility stakeholders in the decision-making process. The thematic analysis potential of the method is shown in figures which present the efficiency and sustainability of transport modes in different contexts. Recommendations for individual users, the mobility industry, and political decision-makers can be derived from these figures to implement measures for more sustainable and efficient mobility. Results include, that i) Individual users are more cost-efficient when using shared mobility services depending on the annual mileage (below 5,000 km for cars); ii) electric vehicles will be the most cost-efficient propulsion type and, at the same time, have the lowest CO2 emissions. The visualized interdependencies between the guiding principles for transport planners and transport modes allow providers of mobility-as-a-service (MaaS) platforms to integrate a variable pricing system according to these principles. Pricing models will be investigated in further studies.

Eco-efficient marine power system with cooled air ventilation by waste LNG cold energy for reefer holds in an ultra-large container ship

This study investigates dissipated heat removal from the internal cargo holds of an ultra-large container ship utilizing an LNG waste cold source. The reefer containers in the cargo hold dissipate heat to maintain certain freight conditions. While the extracted air from the atmosphere absorbs cold energy during LNG vaporization, it prevents a temperature increase inside the cargo holds by supplying cooled air. Herein, the marine power system is an electric propulsion type with a combined gas turbine electric and steam system. The cooled-airflow-ventilation system linked to the power system is evaluated regarding energy and exergy flows and greenhouse gas emissions. Cooled-airflow-ventilation performs efficiently as its coefficient-of-performance becomes twice that of atmospheric-airflow-ventilation when the reefer container box temperature is above zero and heat dissipation is high. Moreover, cooled-airflow-ventilation reduces the maximum-continuous-rating and improves the exergy efficiency. LNG waste cold source utilization benefits the response to the enforced regulation of ship greenhouse gas emissions. However, a high atmospheric temperature makes dissipated heat removal difficult. Consequently, cold energy cannot be provided to all cargo holds. The lower the box temperature is; the more cargo holds that can utilize cold energy.

New Technologies for Natural Gas Supply in the Baltic Sea – Economic Aspect

Purpose: Modern technology is contributing to the development of projects and modifications to existing Liquefield Natural Gas (LNG) import terminals that enable efficient distribution of liquefied natural gas. When considering Small Scale LNG (SSLNG), it is important to consider the amount of LNG demand and how the feedstock will be distributed. This paper describes SSLNG technology initiatives that guarantee fast and attractive returns in the medium term. Design/Methodology/Approach: In the first part of the paper, theoretical background of LNG is described. The SSLNG supply chain and the main actors in the distribution process were characterized. Findings: The method of determining the LNG price, which depends on many components, was determined. Distribution costs were classified with reference to the SSLNG fleet in terms of the type of propulsion used. The benefits of implementing SSLNG were indicated. In the next part of the study, the predicted number of vessels which will use LNG as propellant was simulated. This made it possible to determine the price of LNG. The analysis was performed using the Monte Carlo method on the example of the Baltic Sea with a forecast to 2026. Practical implications: SSLNG technology with reduced investment requirements and a short commissioning period reduces the uncertainty of project timing. Depending on the choice of LNG management, different actors are involved in the supply chain. The analyses presented here show that participants in the distribution process have a significant impact on network integration. SSLNG enables the addition of capacity to have the ability to handle increased demand for LNG. Thus, it is possible to synchronize the supply chain. Originality value: For the first time, to our knowledge, determining the situation, anticipating, monitoring, and responding to changes is the basis for designing SSLNG for optimal use.

Electrification of Urban Waste Collection: Introducing a Simulation-Based Methodology for Technical Feasibility, Impact and Cost Analysis

Electrification is a potential solution for transport decarbonization and already widely available for individual and public transport. However, the availability of electrified commercial vehicles like waste collection vehicles is still limited, despite their significant contribution to urban emissions. Moreover, there is a lack of clarity whether electric waste collection vehicles can persist in real world conditions and which system design is required. Therefore, we introduce a multi-agent-based simulation methodology to investigate the technical feasibility and evaluate environmental and economic sustainability of an electrified urban waste collection. We present a synthetic model for waste collection demand on a per-link basis, using open available data. The tour planning is solved by an open-source algorithm as a capacitated vehicle routing problem (CVRP). This generates plausible tours which handle the demand. The generated tours are simulated with an open-source transport simulation (MATSim) for both the diesel and the electric waste collection vehicles. To compare the life cycle costs, we analyze the data using total cost of ownership (TCO). Environmental impacts are evaluated based on a Well-to-Wheel approach. We present a comparison of the two propulsion types for the exemplary use case of Berlin. And we are able to generate a suitable planning to handle Berlin’s waste collection demand using battery electric vehicles only. The TCO calculation reveals that the electrification raises the total operator cost by 16–30%, depending on the scenario and the battery size with conservative assumptions. Furthermore, the greenhouse gas emissions (GHG) can be reduced by 60–99%, depending on the carbon footprint of electric power generation.

An automated system analysis and design tool for spacecrafts

In this paper, a generic full-system estimation software tool is introduced and applied to a data set of actual flight missions to derive a heuristic for system composition for mass and power ratios of considered sub-systems. The capability of evolutionary algorithms to analyse and effectively design spacecraft (sub-)systems is shown. After deriving top-level estimates for each spacecraft sub-system based on heuristic heritage data, a detailed component-based system analysis follows. Various degrees of freedom exist for a hardware-based sub-system design; these are to be resolved via an evolutionary algorithm to determine an optimal system configuration. A propulsion system implementation for a small satellite test case will serve as a reference example of the implemented algorithm application. The propulsion system includes thruster, power processing unit, tank, propellant and general power supply system masses and power consumptions. Relevant performance parameters such as desired thrust, effective exhaust velocity, utilised propellant, and the propulsion type are considered as degrees of freedom. An evolutionary algorithm is applied to the propulsion system scaling model to demonstrate that such evolutionary algorithms are capable of bypassing complex multidimensional design optimisation problems. An evolutionary algorithm is an algorithm that uses a heuristic to change input parameters and a defined selection criterion (e.g., mass fraction of the system) on an optimisation function to refine solutions successively. With sufficient generations and, thereby, iterations of design points, local optima are determined. Using mitigation methods and a sufficient number of seed points, a global optimal system configurations can be found.

The effect of batoid inspired undulating motions on the propulsive forces of a circular planform

This study explores the nature of forces developed by a batoid-inspired undulating circular planform. The forces that arise from this type of fin-based propulsion have two components, one due to added mass effects and a second one due to circulation. The present work studies the impact of specific fin kinematic parameters on the individual contributions of these components. Numerical simulations are performed on a deforming boundary fitted grid around an undulating circular planform. Flow physics and force generation are analyzed at Reynolds numbers up to 500. A detailed analysis is presented of the impact of wavenumber, amplitude of the fin traveling wave, and Strouhal number on propulsive forces using flow contours and pressure distributions on the planform. The sway coefficient increases with decrease in wavenumber, whereas the thrust coefficient reaches a maximum at a wavenumber of one. The yaw moment coefficient increases up to wavenumber of 1.5 and remains nearly constant after. For the cases studied, circulation has a larger impact compared to added mass effects in the overall force generation, and the role of edge vortices is explored in detail. The wake formed during half of the fin flapping cycle has two distinctive parts. One part is shed as an edge vortex toward the planform circumference and the other part is shed from the trailing edge of the planform, where both vortex structures are attached. These two vortices are of same sign. Over the next half-cycle a similar couple, but with opposite sign, is shed and inter-locks with the previous pair. The edge vortices on both sides of the planform are connected like a horse-shoe. The results enable a better understanding of the link between batoid-like undulatory fin kinematics and propulsive force generation and can help in the design and control of bio-inspired underwater vehicles.

EVALUATION OF THE PERFORMANCE OF THE PROPULSION LEDOREZNOY MACHINES

Purpose: the aim of the analysis justify the selection of the type of propulsion ledoreznoy the machines with a specific working body.
 Design / methodology / approach: we present the averaged values of thrust for various types of working bodies LRM (disk, bar, bolt cutters). The calculated values of the thrust force of LRM equipped with various propellers (wheel, crawler, rotor-screw) are presented. 
 Findings: the Advantage of the rotor-screw propellers is the absence of a rigid dependence of the thrust force on the weight of the machine. In addition, the rotors can provide a margin of buoyancy when the ice breaks and the machine enters the water.
 Research limitations/implications: it was found that the rotor-screw propellers have an excessive supply of traction, while the wheel-its disadvantage. Some specific properties of working bodies which, impose special requirements to the choice of propellers, are analyzed. The questions of the influence of the type of propulsion on the safety of work in the ice areas.
 Originality / value: the presented criteria and conditions can be the basis for the method of choosing the type of ice-cutting machine with any working body.

Triple Langmuir probe measurements in a low-energy tongue-flared configuration plasma thruster

The pulsed plasma thruster is a type of electric propulsion, which has attracted a lot of interest due to its application in microsatellite. In this study, a side-fed, tongue-flared configuration PPT is operated at 2 J and a triple Langmuir probe is used to measure the plasma characteristics, namely electron temperature, Te and electron density, ne. These measurements were carried out in both perpendicular and parallel planes to the thruster electrode. The radial profiles of plasma expulsion in both planes were also measured and compared. The mean ion velocity was calculated from the plasma transit times from the teflon target where surface discharge was first initiated to the probe positions. These plasma characteristics were compared to other systems operated over a wide range of energy.

The Symmetric Nature of the Position Distribution of the Human Body Center of Gravity during Propelling Manual Wheelchairs with Innovative Propulsion Systems

Objective: The main objective of the tests conducted was to analyze the position variability of the human body’s center of gravity during propelling the wheelchair, and to demonstrate the properties enabling the description of this variability by means of plane figures with a symmetry axis. A secondary objective was to show the impact of the used manual propulsion type and the wheelchair inclination angle in relation to the plane on the dimensions of the position variability areas of the center of gravity. Method and materials: Three patients participated in the research representing 50 centiles of anthropometric dimensions. Each patient carried out fifteen measurement tests on three wheelchairs for three inclination angles of the wheelchair frame in relation to the level. Each measurement test consisted of five propulsion cycles for which the positions of the center of gravity were determined with the sampling frequency of 100 Hz. The measured positions of the center of gravity were approximated with ellipses containing 95.4% of the measurements conducted, assuming their dimension scaling basis in the form of the double value of standard deviation defined based on the registered results. Results: Based on the measurements conducted, the average values of five ellipses parameters were determined for nine cases in which a variable was the type of wheelchair propulsion and its inclination angle in relation to the level. The area of the highest variability of the position of the center of gravity was measured for the wheelchair with a multispeed transmission. The average dimensions of the ellipse semi-axis amounted to 108.53 mm for the semi-axis a and 29.75 for the semi-axis b, the average position of the ellipse center amounted to x = 114.51 mm and y = −10.53 mm, and the average inclination angle of the ellipse α amounted to −6.92°. The area of the lowest variability of the position of the center of gravity was measured for the wheelchair with a hybrid transmission. In this case, the average dimensions of the ellipse semi-axis amounted to 64.07 mm for the semi-axis a and 33.85 for the semi-axis b; whereas, the average position of the ellipse center amounted to x = 245.13 mm and y = −28.24 mm, and the average inclination angle of the ellipse α amounted to −0.56°.

CLASSIFICAÇÃO E DESCRIÇÃO TÉCNICA DAS EMBARCAÇÕES PESQUEIRAS ATUANTES EM SANTARÉM, ESTADO DO PARÁ

This study aimed to characterize fishing boats in the municipality of Santarém. The data were collected through interviews carried out from January 2017 to December 2018, in places where the fishing fleet was busy and at various points the edge of the city. During this period, 150 semi-structured forms were applied mainly to the owners or agents of fishing boats and fishermen who landed fish, as well as the monitoring of landings and direct observations. The fishing boats in activity in the municipality and registered in the present study had dimensions varying from 3 to 20 meters in length, all units of the fishing fleet had the construction and structure in wood evidencing an artisanal production system. The fishing fleet was classified into seven categories: “cascos”, canoes, motorized canoes, “sapiaras”, “rabetão”, “bajaras” and “geleiras”, which differ in size, model and type of propulsion. The most frequent boats in the ports of Santarém were the group of canoes, in descending order of contribution, are the “rabetas”, canoes, “cascos”, “rabetão” and “sapiaras”, followed by the glaciers and “bajaras” boats. The physical conditions of the floodplain environment, with numerous canals, “paranás” and lakes that suffer fluctuations of the water level are determinant factors for the size of the boats justifying the great use of the hooves and canoes actually operating in the regional fishing activity, associated with a variation of fishing techniques that demand a differentiated means of transport. Therefore, this study proves that the fishing sector plays an important role in the regional economy, besides supplying the Santarém city.

A Review of a Biomimicry Swimming Robot using Smart Actuator

Biomimicry-based robotic mobility is a newer subgenre of bio-inspired design and it's all about applying natural concepts to the development of real-world engineered systems. Previously, researchers used actuators such as motors, pumps, and intelligent materials or intelligent actuators to build many biomimicry robots. Due to the field's growing interest, this study will examine the performance of several biomimicry robots that have been built based on their different design, the type of material the robot utilizes, and the type of propulsion for the robot to swim while providing huge thrust. Robots must not only design such an animal, but its maneuverability and control tactics must also be tied to wildlife to provide the finest impersonation of biological life. Fish propulsion can be separated into two categories which are body and/or caudal fins (BCF) and median and/or paired fins (MPF). The old propeller system in underwater robot usually uses motor and pump. Many researchers have begun developing smart materials as drivers in recent years that can be grouped into four categories: shape memory alloy SMA, ionic polymer metal composite IPMC, lead zirconate titanate (PZT) and pneumatic soft actuator as replacement for pump or motor. Varied materials produce different result and can be applied for different propulsion modes. Future researchers working on biomimetic fish robots will be guided by the findings of this study.

MPD Thruster Technology and Its Limitations

It was realized earlier that chemical propulsion systems utilize fuel very inefficiently, which greatly limits their lifespan. Electric propulsion is into existence to overcome this limitation of chemical propulsion. The magnetoplasmadynamic (MPD) thruster is presently the most powerful form of electromagnetic propulsion. It is the thruster’s ability to efficiently convert MW of electric power into thrust which gives this technology a potential to perform several orbital as well as deep space missions. MPD thruster offers distinct advantages over conventional types of propulsion for several mission applications with its high specific impulse and exhaust velocities. However, MPD thruster has limitations which limits its operational efficiency and lifetime. In this paper, the thruster limitations are reviewed with respect to three operational limits i.e., the onset phenomenon, cathode lifetime, and thruster overfed limits. The dependence and effects of the operational limits on each other is compared using different empirical models to derive a scaling factor that has been found for each geometrical arrangement; a limiting value exists beyond which the operation becomes highly unsteady and electrode erosion occurs. Along with reviewing and proposing methods to overcome power limitations for MPD thrusters, the relation between exit velocity and ratio of electrode’s radius is also verified using Maecker’s formula.

Research on the underwater noise radiation of high pressure water jet propulsion

High pressure water jet propulsion is a new type of propulsion, which has the characteristics of simple system structure, small energy loss in the water inlet duct, easy vectored control, without additional drag force and so on. Underwater jet noise radiation of high pressure waterjet propulsion is an important factor that would directly determine the stealth performance of underwater vehicles. A co-simulation method combining the CFD (Computational Fluid Dynamics) and CAA (Computational Aeroacoustics) was used in this paper to study and analyze the underwater jet noise radiation characteristics of high pressure water jet propulsion. The Realizable k-ε turbulence model was used to numerically simulate the flow field of waterjet. And the FFT processing of the flow field results were implemented by use of the Actran iCFD module in order to obtain the sound source of the waterjet radiation. Then, the Lighthill acoustic analogy theory was utilized to achieve the underwater jet noise radiation characteristic. Consequently, the effects of inlet velocity on the underwater jet noise radiation characteristics of high pressure waterjet propulsion were researched. The results indicated that the underwater jet noise radiation of high pressure water jet propulsion mainly comes from the mixing area where is the 8–10 times diameter away from the nozzle outlet, and the increase of the inlet flow velocity would enlarge the sound pressure level of the underwater jet noise radiation. In addition, the underwater noise jet radiation is directional and mainly propagates in the axial direction. However, the inlet velocity has little influence on the frequency domain characteristics of underwater jet noise radiation and the underwater jet noise radiation has high energy below the frequency 200 Hz. The research provides theoretical guidance for reducing the underwater jet noise radiation of high pressure waterjet propulsion and improving the stealth performance of underwater vehicles.

Analysis of unstable behavior of planing craft speed using the qualitative theory of dynamical systems

This paper deals with the inherent instability observed in the speed of a planing type craft. In the case of displacement craft, the systems governing the speed are stable hence closed-loop control is trivial. In the case of planing craft, however, there may exist instability in their speed. By using the Qualitative Theory of Dynamical Systems (QTDS), this paper shows that there may exist a set of speeds in which planing craft are not able to achieve adequate stability. This instability problem cannot be acceptable in many applications (such as that examined in this paper, an Unmanned Surface Vehicle, USV, of planing craft type). The observed instability is explained by means of the appearance of bifurcations which bring new attractors to the state space, such as equilibrium points or limit cycles. This paper proposes a novel solution to manage the vessel instability behavior. This is done by way of increasing the droop characteristic in the propulsion thrust with respect to speed. By increasing the droop, the system becomes more robust. The key advantage of this approach is that it is achieved by way of modifying the propulsion controller rather than by changing the hydrodynamic profile of the vessel, the mass distribution or by adding extra control surface (i.e., flaps). Resulting in a more cost-effective control system. Furthermore, due to this method acting on propulsion and its control, it is compatible with the other methods aforementioned. Stability analysis is undertaken. This analysis is very general, because it considers a wide range of controller and propulsion systems. Open-loop control and analysis into different types of propulsion is also presented. The effect of each propulsion type on stability is explained. In addition, the effect in the control loop of the electro-mechanical actuators inaccuracy (dead-zone) has also been analyzed. The paper explains that this inaccuracy, though small, can make the speed oscillate in planing craft. A practical implementation of this analysis is validated by way of sea trials with a real planing craft.

Water and xenon ECR ion thruster—comparison in global model and experiment

Gridded ion thrusters are one of the most commonly used types of electric propulsion, and alternative propellants have been studied for miniature ion thrusters to meet the demand of propulsion systems for micro-/nano-satellites. Water is a candidate as an alternative non-pressurized propellant for a CubeSat thruster. It is consistent with the CubeSat concept of short-term and low-cost development. In this paper, the characteristics of a miniature water ion thruster were compared with those of a xenon one using a global model and experiments. The dependence of the performance on the mass flow rate and the input microwave power was examined, and the effects of dissociation and doubly charged ions were directly measured by a quadrupole mass spectrometer. The estimates on the model were compared against experimental results for both propellants, and the performance of the thruster operating on xenon propellant was compared to the performance operating on water propellant. In the comparison between the estimates and the experimental results, the two differences were discussed: the one between water and xenon and the other from the experimental result in both cases. A performance decrease in the propellant utilization efficiency and the specific impulse cannot be avoided when using water as a propellant in an ion thruster. However, the ion production cost did not increase, and it showed the capability of water ion thruster for CubeSat application taking advantage of safety, low cost, non-pressurized system, and human-friendliness of water when used as a propellant.