ResearchPaper
Space New Technologies
Hassan Naseh; Ali Alipoor
Abstract
The main purpose is to introduce the performance system design and optimization method of aerospike nozzle for different aero-space conditions. For this purpose, some of the important parameters of the aerospike nozzle structure and cold flow condition tests in the nozzle optimization are studied. The ...
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The main purpose is to introduce the performance system design and optimization method of aerospike nozzle for different aero-space conditions. For this purpose, some of the important parameters of the aerospike nozzle structure and cold flow condition tests in the nozzle optimization are studied. The methods of designing the Aerospike nozzle and its governing equations are described and the proposed design model is described and important factors are expressed in this type of nozzle. therefore, the design of a complete nozzle is made by aerospike and is supported by an existing design sample. Then, in order to optimize the nozzle, three cuts of 20%, 40% and 60% of the nozzle end are analyzed. The standard for comparison and optimization in these three slices is the Mach number of the output current. The results of this comparison show that the most efficient aerospike nozzle is a 40% cut nozzle based on the flow charts and contours of this aerospace nozzle.
ResearchPaper
Space Science and Technology
Amirhamzeh Farajollahi; Reza Firuzi; Mohammad Reza Salimi; Mohsen Rostami
Abstract
In this study, the effects of geometry and spiral rifling like guides inside the injection nozzle on the performance of an engine are investigated, using AVL Fire software. To do so, firstly injectors with different nozzle geometries and their resultant spray patterns were simulated. Numerical results ...
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In this study, the effects of geometry and spiral rifling like guides inside the injection nozzle on the performance of an engine are investigated, using AVL Fire software. To do so, firstly injectors with different nozzle geometries and their resultant spray patterns were simulated. Numerical results of this step show that creation of spiral rifling like guides inside the nozzle increases the spray cone angle and improves fuel atomization quality. In the next step, effects of using forgoing nozzle geometries on sample engine characteristics were studied and the related results compared to those of common cylindrical injectors. Numerical results of this step clearly show the superior performance of nozzles with spiral rifling like guides. In this case, SFC reduces up to 32 percent while the engine power and it's torque rises more than 63 percent. Also the amount of pollutants like NOx reduces 12 percent with respect to common cylindrical nozzles.
ResearchPaper
Hadiseh Karimaei; Hadiseh Karimaei
Abstract
In this research, design and simulation of a single capillary injector and three-hole circular injector plate of a 10N Hydrazine monopropellant thruster were performed. Ansys Fluent software was used to simulate the injector and injector plate . Volume of fluid (VOF) method was used to simulate such ...
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In this research, design and simulation of a single capillary injector and three-hole circular injector plate of a 10N Hydrazine monopropellant thruster were performed. Ansys Fluent software was used to simulate the injector and injector plate . Volume of fluid (VOF) method was used to simulate such a flow and turbulence was simulated by k-e model. The characteristics of the injector and injector plate including mass flow rate and average velocity in the injector nozzle were calculated by changing the inlet pressure. The results showed that the injector and the injector plate have the ability to supply the desired mass flow rate of the monopropellant thruster at a known design pressure. In fact the capillary injector has replaced swirl injector with hollow cone spray used in the previous version of this thruster. The dimension of the chamber was significantly reduced by using the capillary injector, which reduces both the volume of the expensive iridium catalyst and weight of the thruster.
ResearchPaper
sajjad Davari; Hadiseh Karimaei; Mohammad Reza Salimi; Hassan Naseh
Abstract
Monopropellant thruster are used to inject a satellite into orbit or control its position on three axes in space missions. One of them is hydrazine thruster which is widely used. In this research, design of the injector, decomposition chamber and nozzle of a 10N hydrazine monopropellant thruster have ...
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Monopropellant thruster are used to inject a satellite into orbit or control its position on three axes in space missions. One of them is hydrazine thruster which is widely used. In this research, design of the injector, decomposition chamber and nozzle of a 10N hydrazine monopropellant thruster have been performed. The capillary injector was designed using Fluent software for this thruster which was able to supply the mass flow rate of the thruster (5 gr/sec). The decomposition chamber contains catalyst granules and its dimensions were selected based on the complete decomposition of hydrazine. The nozzle was designed by RPA software. The validation of the design with RPA software was checked by a numeric code. This code was able to calculate the dimensions of the decomposition chamber based on the amount of hydrazine decomposition. Accordingly, the results of both design methods are strongly consistent with each other. At the end of the design, the final thruster design and drawings were prepared.
Technical Note
Space Science and Technology
Hadiseh Karimaei; Hadiseh Karimaei; Mohammad Reza Salimi; Hassan Naseh
Abstract
In this paper, the catalyst bed of a 10 N hydrazine monopropellant thruster was designed. The catalyst bed is including iridium granules, which is used to decompose the hydrazine in monopropellant thruster. Hydrazine must be decomposed almost completely in the catalytic chamber, because it is a carcinogenic ...
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In this paper, the catalyst bed of a 10 N hydrazine monopropellant thruster was designed. The catalyst bed is including iridium granules, which is used to decompose the hydrazine in monopropellant thruster. Hydrazine must be decomposed almost completely in the catalytic chamber, because it is a carcinogenic chemical fuel and on the other hand, achieving the maximum power from the thruster is also an important goal. As a result, the effect of change in catalytic chamber length on the mass fraction of chemical species including hydrazine, ammonia, nitrogen, and oxygen was studied. Also, after determining the length of the catalytic chamber, the diameter of the nozzle throat corresponding to the same length was determined.
ResearchPaper
physiology and space medicine (astrobiology)
Vajihe Zarrinpour; زهرا حاجابراهیمی
Abstract
A study of the effect of microgravity on the endothelial progenitor cells is useful both in understanding cardiac changes in astronauts and in using microgravity as angiogenic stimuli. The aim of the present study was to investigate the effect of microgravity on VEGFR-2 and CD34 angiogenesis markers. ...
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A study of the effect of microgravity on the endothelial progenitor cells is useful both in understanding cardiac changes in astronauts and in using microgravity as angiogenic stimuli. The aim of the present study was to investigate the effect of microgravity on VEGFR-2 and CD34 angiogenesis markers. Following extraction of progenitor cells from peripheral blood and its confirmation, gene expression was assessed by real-time PCR, and cell viability was assessed by MTT assay. The extracted cells were endothelial progenitor cells in terms of shape and surface markers CD31 and CD144. Microgravity increased the VEGFR-2 gene expression by 3.5 times after 24 hours. CD34 expression increased by 50% after 3 h but reached control level after 24 hours. Microgravity appears to have a positive effect on the expression of angiogenic markers and stimulation of endothelial progenitor cells, and it may be used as a new environment to differentiate these cells into blood vessels and to treat heart disease.
ResearchPaper
Space transportation systems Design (launch site and subsystems,…)
Armin Azodi; Meysam Mohammadi-Amin; Saeed Mahmoudkhani
Abstract
In the present work, the frequency-domain aeroelastic stability analysis of space launch vehicle body in the flight condition of initial launch phase is presented for a range of geometric parameters, structural characteristics, and other parameters such as thrust force. The aeroelastic model is derived ...
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In the present work, the frequency-domain aeroelastic stability analysis of space launch vehicle body in the flight condition of initial launch phase is presented for a range of geometric parameters, structural characteristics, and other parameters such as thrust force. The aeroelastic model is derived using structural assumed modes and quasi-steady aerodynamics. The pressure distribution of subsonic flow on the 3D configuration is determined by boundary element method. Non-uniform Euler-Bernoulli beam including torsion spring junctions along the body with free-free ends is used to model the structure, and its modal analysis is performed by finite difference method. Concluded results illustrate variation in parameters not only could vary the aeroelastic instability boundary, but also might cause the instability type changed (from divergence to flutter), which its main reason is replacement the second instability of the aeroelastic system with the first one. Furthermore, it is demonstrated that the follower thrust force restricts the aeroelastic stability but maintains the instability type.
ResearchPaper
Space subsystems design: (navigation, control, structure and…)
Milad َAzimi; Samad Moradi
Abstract
This paper deals with form-finding and free vibration analysis of a pre-stressed class-one triplex tensegrity structure. The form-finding is performed via a two-step procedure, the nodal coordinates connectivity matrix, and structural element force density determination. Accordingly, the possible states ...
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This paper deals with form-finding and free vibration analysis of a pre-stressed class-one triplex tensegrity structure. The form-finding is performed via a two-step procedure, the nodal coordinates connectivity matrix, and structural element force density determination. Accordingly, the possible states for the nodal coordinates and the structural force density of the triplex prism have been determined by trial and error (based on topology and member type knowledge) to satisfy the force density, and equilibrium matrices rank requirements. Based on different structural topologies, the equation of the motion in the frequency domain for free vibration analysis of the system is derived using the spectral element approach and dynamic shape functions. Simulations are provided for different system heights and the top-bottom aria ratios and compared with the FEM. The numerical simulations in the form of a comparative study of the natural frequencies of triplex tensegrity prism with different heights and cross-sections represent the system’s robustness with different topologies for single or multi-stage applications.
ResearchPaper
Space New Technologies
Hassan Naseh; mostafa jafarpanah
Abstract
The purpose of this paper is to present the cost estimation and optimization of space propulsion systems. Thus, choosing optimal propulsion system (from fuel and oxidizer aspect) is done in order to increase the efficiency and decrease the cost. Also, human resource cost and technology development time ...
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The purpose of this paper is to present the cost estimation and optimization of space propulsion systems. Thus, choosing optimal propulsion system (from fuel and oxidizer aspect) is done in order to increase the efficiency and decrease the cost. Also, human resource cost and technology development time based on the consideration of labor cost effect on the personals motivation have been optimized. To this end, cost estimation and optimization algorithm has been drawn and suggested. The suggested algorithm has two steps. The first step in the algorithm is concern to cost estimation for seven fuel and oxidizer components. In the second step, labor cost and project implementation time is estimated and optimized based on the optimal space propulsion system derived from the previous step. Here, the objective functions are propulsion system technology development cost and time. On the other hand, the purpose is to consider the salary enhancement and consequently efficiency enhancement, time decrease and cost decrease.
ResearchPaper
communications
Javad Ranjbar; Mohammad Fathi
Abstract
In this paper, in order to provide telecommunication coverage for a wide geographical area, the use of a network consisting of an LEO satellite and a Tethered-Balloon equipped with antenna pointing mechanism is proposed. The proposed telecommunication network is able to send the collected data to a mission ...
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In this paper, in order to provide telecommunication coverage for a wide geographical area, the use of a network consisting of an LEO satellite and a Tethered-Balloon equipped with antenna pointing mechanism is proposed. The proposed telecommunication network is able to send the collected data to a mission center outside the covered region and receive the required telecommands, while providing a telecommunication link between the users in the covered region. To control and point the antenna beams towards desired targets, an Adaptive Dynamic Surface Controller is designed. Determining the required operating modes, designing a mode management algorithm and extracting the appropriate reference trajectories for each operating mode are among the discussed issues in this paper. The Uniform Ultimate Boundary (UUB) stability of the closed-loop system is proved and the performance of the control system is studied by simulation. The proposed communication network and control system are able to provide wide telecommunication coverage in remote areas or emergency situations.
ResearchPaper
Space subsystems design: (navigation, control, structure and…)
Ali Kasiri; فرهاد فانی صابری; Vahid Joudakian
Abstract
Many studies have investigated the problem of external disturbance rejection and also increasing the attitude control system's robustness against the parametric uncertainties. Due to stochastic properties, noise effect minimization becomes an interesting and challenging problem in the field of spacecraft ...
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Many studies have investigated the problem of external disturbance rejection and also increasing the attitude control system's robustness against the parametric uncertainties. Due to stochastic properties, noise effect minimization becomes an interesting and challenging problem in the field of spacecraft attitude control that has been underestimated, while control actuators and attitude sensors themselves are important sources of noise generation., the main purpose of this paper is to (i)control the satellite’s attitude and (ii)minimize the variance of output, simultaneously. The Minimum Variance controller, which is considered the simplest type of model predictive controller, has a powerful capability for minimizing the effects of output noise. This feature makes it a suitable control scheme for space-based high-resolution photography missions. so,, we described the conventional Minimum Variance regulator method at first, then an Incremental version of the regulator has been presented to solve the tracking problem. Finally, the generalized minimum variance controller which can control both minimum-phase and non-minimum-phase systems is derived for a high pointing accuracy spacecraft. The simulation results show the efficiency of the proposed controller to restrain the noise effects in a high-resolution tri-stereo imaging mission.
ResearchPaper
Space subsystems design: (navigation, control, structure and…)
Seyyed Rashad Rouholamini; Mohammad Ali Amirifar; Alireza Rajabi; Nooredin Ghadiri Massoom
Abstract
In this paper, by creating and developing a code based on thermodynamics and gas dynamics equations, the performance characteristics of a 1N hydrazine monopropellant thruster such as thrust force, specific impulse, characteristic exhaust velocity, and propellant mass flow rate have been studied theoretically ...
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In this paper, by creating and developing a code based on thermodynamics and gas dynamics equations, the performance characteristics of a 1N hydrazine monopropellant thruster such as thrust force, specific impulse, characteristic exhaust velocity, and propellant mass flow rate have been studied theoretically in terms of reaction chamber temperature. In this regard, by taking into account the adiabatic assumption, the reaction chamber temperature of monopropellant thruster has been analyzed zero-dimensionally using the ammonia dissociation rate as an independent variable under equilibrium and non-equilibrium conditions and it has been analyzed one-dimensionally using the hydrazine and ammonia homogeneous and heterogeneous reaction rate constants. Also, the effect of nozzle throat thermal expansion on reaction chamber pressure, thrust force, and propellant mass flow rate and the effect of reaction chamber pressure on ammonia dissociation rate and consequently on reaction chamber adiabatic temperature under thermodynamic equilibrium conditions have been studied.
ResearchPaper
Space subsystems design: (navigation, control, structure and…)
mahsa javaheri pour; Ahmad Reza Vali; Vahid Behnam Gol; Firouz Allahverdizadeh
Abstract
Proportional navigation is one of the most widely used methods in guiding flying objects. This method requires the rotation rate of the line between the interceptor and the target to calculate the guidance command. For a variety of reasons, including cost savings, simple sensors are used to measure tracking ...
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Proportional navigation is one of the most widely used methods in guiding flying objects. This method requires the rotation rate of the line between the interceptor and the target to calculate the guidance command. For a variety of reasons, including cost savings, simple sensors are used to measure tracking information, including line of sight angle. Therefore, some non-measurable information such as the angular velocity of the line of sight must be estimated using mathematical equations. Due to the noise and other problems, the use of derivatives is not desirable in this situation. Therefore, in this paper, an extended nonlinear observer is used to estimate the angular velocity of the line. Due to the nonlinear dynamics of the intercepting of flying objects, a nonlinear type of observer has been selected. By performing a computer simulation, the correct operation of the proposed observer is shown.
ResearchPaper
Space subsystems design: (navigation, control, structure and…)
Valiollah Shahbahrami; Milad َAzimi; َAlireza Alikhani
Abstract
In this paper, a robust adaptive hybrid control approach based on a combination of super-twisting and non-singular terminal sliding mode control (STNSMC) approaches for vibration and attitude control of a flexible spacecraft with fully coupled dynamic is developed. The proposed adaptation law eliminates ...
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In this paper, a robust adaptive hybrid control approach based on a combination of super-twisting and non-singular terminal sliding mode control (STNSMC) approaches for vibration and attitude control of a flexible spacecraft with fully coupled dynamic is developed. The proposed adaptation law eliminates the need for bounds knowledge of external disturbances and uncertainties. Then an ST-based NSMC generates a continuous control signal to reject the Chattering phenomenon, the non-singular terminal switching control law with the ability to generate continuous control commands to eliminate the chattering phenomenon. Moreover, finite-time convergence is achieved, and the singularity problem has been avoided. The overall stability of the system has been demonstrated using the Lyapunov theory. One of the essential features of the proposed control algorithm is to prevent overestimation of control gains and faster convergence rates comparing to conventional ST and non-singular terminal SMC approaches. The simulations in the form of a comparative study for large-angle maneuver reveal the advantage of the proposed approach.
ResearchPaper
Space subsystems design: (navigation, control, structure and…)
Mohsen Ebrahimi; Amir Farhad Ehyaei
Abstract
In this paper, in addition to investigation and analyzing the dynamic model of a maneuver target, a new method based on the Interaction Multiple Model (IMM) method is presented to solve the tracking problem in presence of measurement noise. In this procedure, two models are used along with an extended ...
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In this paper, in addition to investigation and analyzing the dynamic model of a maneuver target, a new method based on the Interaction Multiple Model (IMM) method is presented to solve the tracking problem in presence of measurement noise. In this procedure, two models are used along with an extended Kalman filter for each model, for estimation of the states related to stochastic target model. To this end, a specific weight is calculated adaptively for each model and the final estimation of the target is obtained from the weighted sum of the modes related to each model. In this paper, second order Markov models are used to better describe the system behavior which leads to a decrease in the number of required motion models. This means that the previous two models are used to decide on the next model, and a much better algorithm is provided than the first-order IMM algorithm.
ResearchPaper
Space systems design (spacecraft, satellites, space stations and their equipment)
Alireza Rajabi; Noordin Qadiri Massoom; Mohammadali Amirifar; Seyyed Rashad Rouholamini; Pouria Mikaniki; Mohammad Ghorbi; Majid Kamranifar
Abstract
The effects of injector pressure drop on the performance of a catalytic reactor are studied experimentally. The injectors were simple orifices. Dynamic interactions between the injector and the reactor determine the transient behavior of the system. Results showed that the injector pressure drop affected ...
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The effects of injector pressure drop on the performance of a catalytic reactor are studied experimentally. The injectors were simple orifices. Dynamic interactions between the injector and the reactor determine the transient behavior of the system. Results showed that the injector pressure drop affected neither the decomposition reaction efficiency nor the ignition delay time. However, pressure response time increased, and pressure roughness decreased with increasing injector pressure drop. Interestingly, the response time curve had a slope change at a 20% pressure drop. As discussed in the paper, the slope change is a result of cavitation phenomena in high pressure drop. It is concluded that cold injector tests are not enough for injector design validation, and performance tests are necessary tasks.
ResearchPaper
Remote sensing
somaye karimpour; Javad Sadidi; Seyed Mohammad Tavakoli Saboor
Abstract
Deep learning is a modern method of image processing and data analysis that has entered the field of urban management with promising results and high potential. The purpose of this study is to investigate data augmentation techniques in improving the results of segmentation of buildings using aerial ...
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Deep learning is a modern method of image processing and data analysis that has entered the field of urban management with promising results and high potential. The purpose of this study is to investigate data augmentation techniques in improving the results of segmentation of buildings using aerial images with high spatial resolution and deep learning method. For this purpose, MSB building data set and MapNet model were used. The model was trained and evaluated in three stages without data augmentation, with data augmentation of geometric transformations and with data augmentation of geometric and photometric transformations. The results of model evaluation showed that using geometric transformations as data enhancement techniques, F-1 and IoU score evaluation criteria have increased by 0.5 and 0.55%, respectively, and using data techniques Incremental geometric and photometric transformations increased by 1.41 and 1.57 percent. This increase was visually observed in the improvement of the segmentation of dense areas of the building and the discontinuity of large-scale buildings.
ResearchPaper
Space systems design (spacecraft, satellites, space stations and their equipment)
Omid Shekoofa; Farhad Bagheroskouei; Reza Amjadifard
Abstract
In this paper, the feasibility and performance of using solar arrays equipped with sun concentrators, along with other conventional solar array structures, in CubeSats, is investigated for the first time. For this purpose, seven different structures of solar arrays have been defined and implemented for ...
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In this paper, the feasibility and performance of using solar arrays equipped with sun concentrators, along with other conventional solar array structures, in CubeSats, is investigated for the first time. For this purpose, seven different structures of solar arrays have been defined and implemented for more than 24 different CubeSat configurations from 0.25U to 27U. Then, by calculating important system-level parameters such as power generation density, power generation cost, reliability of solar arrays, and also a newly proposed parameter, called shape fit factor, the performance of these structures for the introduced configurations are evaluated and compared. To this end, and by considering rational coefficients, a cost function consisting of the four above-mentioned parameters is defined as the degree of merit of different solar array structures used in each CubeSat configuration. The results show that alongside the use of deployable solar arrays, using concentrating solar arrays can provide new capabilities for CubeSats to overcome the challenge of generating sufficient power.
ResearchPaper
space law
Negar Mofakham Naser Eslami; Ahmad Momeni rad; Seyed Ahmad Tabatabai
Abstract
Today, one of the main concerns of the Committee for the Peaceful Use of Outer Space (COPUOS) and its subcommittees is the issue of militarization in space law. Top space countries such as the United States, Russia and China have added to this concern by using advanced space military equipment. Therefore, ...
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Today, one of the main concerns of the Committee for the Peaceful Use of Outer Space (COPUOS) and its subcommittees is the issue of militarization in space law. Top space countries such as the United States, Russia and China have added to this concern by using advanced space military equipment. Therefore, the international community must look for desirable and practical solutions to solve this problem in order to prevent militarization and the creation of an arms race in space. Based on this, the present article tries to investigate the military prohibitions governing space activities in order to prohibit such activities in outer space by analyzing the military use of space and legal documents and explaining the conventional and customary system governing space treaties and by examining some dual-use space-based weapons; Conduct a descriptive analysis and reveal more about the negative aspects of the military use of space.
ResearchPaper
Space subsystems design: (navigation, control, structure and…)
Abbas Dideban; Alireza Ahangarani Farahani
Abstract
This paper presents a new control methodology based on Continuous Time Delay Petri Nets (CTDPN) tool for the attitude control of satellite simulator. The graphical and mathematical features of this tool help the expert designer to design an appropriate controller using graphical model easily, and then ...
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This paper presents a new control methodology based on Continuous Time Delay Petri Nets (CTDPN) tool for the attitude control of satellite simulator. The graphical and mathematical features of this tool help the expert designer to design an appropriate controller using graphical model easily, and then apply the necessary changes to the mathematical model. In this approach, the controller gains are derived from the states and some other variables. Thus, the system states and variables must be available. The new gain tuning algorithm consists of three stages. First, A simulation environment is made for mathematical modeling based on the CTDPN tool and controller design. Secondly, using optimal methods, the controller gains are calculated at any given time and the data are collected. Finally, using the database, a relationship between the set of variables and the gains are derived. Experimental results indicate the promising performance of the controller in comparison to the conventional controller applied to the satellite simulator platform. The results indicate that the designed controller is robust against variation of parameters, as the controller gains are tuned based on the system state and variables.
ResearchPaper
Space transportation systems Design (launch site and subsystems,…)
حجت قاسمی; Seyed Mohammadreza Mahmoudian; Noordin Qadiri Massoom; Seyyed Rashad Rouholamini; Pouria Mikaniki; Asghar Azimi
Abstract
The aim of the present research is to obtain the ability to use the cryogenic propellant engines on a laboratory scale. In this regard, it is necessary to build some experimental motors and investigate the their performance parameters. The liquid oxygen as a common oxidizer and ethanol as a green fuel ...
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The aim of the present research is to obtain the ability to use the cryogenic propellant engines on a laboratory scale. In this regard, it is necessary to build some experimental motors and investigate the their performance parameters. The liquid oxygen as a common oxidizer and ethanol as a green fuel have been selected as propellant components. The engine is designed to produce 400 kgf force at the nominal condition. The pintle type injector has been chosen in which liquid oxygen and fuel are flowed in the axial and radial directions, respectively. The combustion chamber has been protected against overheating by applying the regenerative cooling. However, the laboratory feature of the engine design has provided the using of water instead the cooling propellant. All main components of the engine such as injector, igniter, and flow controllers, are examined by the cold tests. A comprehensive test facility is designed and set up for hot fire tests in which the performance of almost all parameters can be evaluated. Fifteen fire tests have been performed. Maximum obtained pressure and evaluated combustion efficiency were about 75% of design values.
ResearchPaper
Space subsystems design: (navigation, control, structure and…)
سید حمید جلالی نائینی; Ali Arabian Arani
Abstract
The miss distance analysis of the first-order explicit guidance law (EGL) is carried out using linearized equation of motion in the normalized form in order to obtain normalized miss distance curves. The initial heading error, constant target, acceleration limit, radome refraction error, and fifth-order ...
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The miss distance analysis of the first-order explicit guidance law (EGL) is carried out using linearized equation of motion in the normalized form in order to obtain normalized miss distance curves. The initial heading error, constant target, acceleration limit, radome refraction error, and fifth-order binomial control system are considered. Moreover, body rate feedback is added to the explicit guidance law as a well-known classical compensation method of the radome effect as in proportional navigation. The analysis is performed for different values of the power of the alpha function, defined as the time decrease rate of the zero-effort miss to unit control input. As a special case, the EGL with unit power gives the first-order optimal guidance strategy for minimizing the integral of the square of the commanded acceleration during the total flight time. For the performance/stability analysis, the rms miss distance versus turning rate time constant and radome slope can be plotted for different values of the power of alpha function.
ResearchPaper
Space subsystems design: (navigation, control, structure and…)
Morteza Tayefi; رامین کمالی مقدم
Abstract
To create drag and reduce the speed of space payloads in the phase of entering the atmosphere, the payload body itself can be used as brake mechanisms without using additional tools. The approach analyzed in this paper is the separation of the nose and then the stability of the cylindrical body in horizontal ...
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To create drag and reduce the speed of space payloads in the phase of entering the atmosphere, the payload body itself can be used as brake mechanisms without using additional tools. The approach analyzed in this paper is the separation of the nose and then the stability of the cylindrical body in horizontal or vertical mode. First, by
numerical solution, the cylindrical body is aerodynamically simulated in the flight conditions entering the
atmosphere, and the location of the center of mass is designed to achieve static stability. Then, by developing the equations of motion of atmospheric reentry using aerodynamic coefficients and derivatives calculated by DATCOM, the flight parameters for both modes are compared and evaluated. The simulation results show that the horizontal flight is more efficient and is able to create better conditions for opening the parachute and landing. Another advantage of atmospheric reentry flight in horizontal mode is the proper distribution of aerodynamic heating and reduction of heat load in certain points of the payload.
ResearchPaper
physiology and space medicine (astrobiology)
maryam salavatifar; Nilofar Mosallaei; Ali Hatef Salmanian
Abstract
Gravity is an influential force on living organisms on earth, including microorganisms. E. coli O157: H7 causes complications such as bloody diarrhea and hemolytic uremic syndrome in humans and immunization is the main way to fight it. Subunit B of Shiga-like toxin type 2 (STX2B), binding agent of bacterial ...
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Gravity is an influential force on living organisms on earth, including microorganisms. E. coli O157: H7 causes complications such as bloody diarrhea and hemolytic uremic syndrome in humans and immunization is the main way to fight it. Subunit B of Shiga-like toxin type 2 (STX2B), binding agent of bacterial toxin to target cells, is a candidate for the recombinant vaccine to prevent disease. Due to the quantitative and qualitative increase in the expression of some recombinant proteins under microgravity, the STX2B recombinant protein expression was examined under simulated microgravity conditions on clinostat device. After confirmation of the recombinant by immunological methods, its expression was performed under microgravity and after the protein purification by chromatographic column, its amount was measured. The results showed that despite the decrease in expression under microgravity, which was probably due to lack of proper aeration of the culture medium, recombinant protein was still produced under microgravity condition.
ResearchPaper
Space Ground Segment: receiving, transmitting, controlling and data processing
سیدحسن صدیقی; Afshin Eskandari
Abstract
In this paper, Design, optimization and implementation of a Transparent Pseudo-Noise satellite Ranging relay is presented. CCSDS and DSN standards was studied for requirements of on board harware for LEO satellites and ground station. To optimize the performance of the relay, a ground station for two-way ...
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In this paper, Design, optimization and implementation of a Transparent Pseudo-Noise satellite Ranging relay is presented. CCSDS and DSN standards was studied for requirements of on board harware for LEO satellites and ground station. To optimize the performance of the relay, a ground station for two-way ranging system was modeled in MATLAB according to the DSN standard architecture. The effects of non-ideal hardware for Implementation of on-board relay was simulated. The simulation results confirmed that the designed transparent relay hardware satisfies the requirements of CCSDS and DSN ranging standards system and has no detrimental effect on it. Finally, the implemented relay was tested with a Transceiver similar to the ranging Transceiver was confirmed for operation.
ResearchPaper
safety in space
Mohammad Nadjafi; Hassan Naseh; Mehrdad Sedigh Koochaki
Abstract
The Monopropellant Hydrazine Propulsion system is one of the most widely used types of single-agent propulsion systems to control the position or correction of satellites in orbits. This system consists of combustion chamber subsystems (catalyst bed, catalyst, nozzle, and cap), fuel and fuel tank, high-pressure ...
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The Monopropellant Hydrazine Propulsion system is one of the most widely used types of single-agent propulsion systems to control the position or correction of satellites in orbits. This system consists of combustion chamber subsystems (catalyst bed, catalyst, nozzle, and cap), fuel and fuel tank, high-pressure tank, control valves, and interface pipes. In this paper, the MPHP system (as a case study) is described in detail, and then critical risks are identified by creating FMECA tables on the case study in the design phase. Based on the proposed FMCEA flowchart, potential failure modes are identified. In the next step, decisions and corrective actions are formulated regarding the inherent failures of the system. Finally, the necessary measures to reduce the risks will be taken according to the system's failure modes, and the reduction of the identified risks to an acceptable level is presented. The attained results show that the catalyst decomposition chamber, catalyst bed, inlet flow control valve, and propellant management facilities units have the highest risk index values (RPN), respectively. For this purpose, corrective measures have been suggested for each of these.
ResearchPaper
investigating space radiation
Roghieh Karimzadeh Baee; Hamideh Daneshvar; Amirhossin Ahmadi; Parvin Sojoodi
Abstract
With the advent of GaN technology, achieving microwave power with high efficiency by solid-state devices has become more available. Therefore, the use of SSPA amplifiers with GaN technology in satellites, especially LEO satellites, has been considered. space radiation can affect the performance and ...
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With the advent of GaN technology, achieving microwave power with high efficiency by solid-state devices has become more available. Therefore, the use of SSPA amplifiers with GaN technology in satellites, especially LEO satellites, has been considered. space radiation can affect the performance and reliability of components in space systems, which needs to be investigated. One of the most important technologies that can be affected by radiation effects is GaN transistors. In this paper, the effect of TID on GaN transistors in the SSPA amplifier board is investigated. Since commercial components have been used in the engineering sample of the SSPA amplifier and the calculations obtained from the RDM estimates under the worst conditions show that it is necessary to conduct a test for these components, the radiation resistance test was performed for this amplifier. The results of the test conducted in this article show that the SSPA GaN board has radiation tolerance up to a dose of approximately 16 krad. Therefore, mismatched GaN transistors are resistant up to this amount of dose. This is while the sequencer board actually has less tolerance than 5.5 krad
ResearchPaper
Space New Technologies
Sadjad Samipour; Alireza Toloui
Abstract
Development in the aerospace industry is linked to the continuous pursuit for lightweight designs. Open-architecture composite structures are a new and novel use of composites for minimal weight component design. It is reasonable to use efficient and advanced techniques such as radial braiding in manufacturing ...
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Development in the aerospace industry is linked to the continuous pursuit for lightweight designs. Open-architecture composite structures are a new and novel use of composites for minimal weight component design. It is reasonable to use efficient and advanced techniques such as radial braiding in manufacturing of composite lattice tubular structures. In this article an aerospace composite lattice tubular structure with a braided reinforcement system is studied. A method is developed to determine the parameters of the preform reinforcement. A new process has been created for the manufacture of lattice structure with a braided reinforcement system. A methodology has been developed for determining the technological parameters of radial braiding. A sample structure is manufactured and tested. Experimental studies of lattice structure samples were carried out in order to verify the methods for determining mechanical, structural, and technological parameters.
ResearchPaper
Infrastructure (labs, sensors, software,…)
Javad Haghshenas; Reza Sharifi Hafshejani
Abstract
In this paper, a step-by-step laboratory procedure for performing a satellite's payload’s alignment measurement is presented. Four highly accurate theodolites are used along with two or more alignment corner cube to accurately extract the final attitude. Theodolites are arranged around the ...
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In this paper, a step-by-step laboratory procedure for performing a satellite's payload’s alignment measurement is presented. Four highly accurate theodolites are used along with two or more alignment corner cube to accurately extract the final attitude. Theodolites are arranged around the satellite in such a way that they have a clear direct view of the alignment cubes mounted on the payload and the satellite. Two theodolites should point to the payload’s alignment cube and the other two theodolites must point to the satellite’s alignment cube. Each theodolite must see at least one other theodolite, directly. Finally, by forming the coordinates systems of the payload and satellite in the theodolites coordinate system along with using the coordinate transfer matrices, the payload alignment correction matrix will be extracted in detail. The total method accuracy is within the order of few arcseconds.
ReviewPaper
Space New Technologies
Pedram Hajipour; Roghieh Karimzadeh Baee; Houman Zarrabi; Roghayeh Doost; Leila mohammadi
Abstract
According to the technical specifications of the future generations of telecommunication (the fifth generation and later), which should provide new services with very high data rates in the minimum time and a wide coverage, as well as the exponential increase in traffic, the use of combined space-air ...
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According to the technical specifications of the future generations of telecommunication (the fifth generation and later), which should provide new services with very high data rates in the minimum time and a wide coverage, as well as the exponential increase in traffic, the use of combined space-air networks Land is essential. It should be noted that the management of this type of combined networks has major challenges in providing such services. Meanwhile, the intelligent management of resources in satellite-based hybrid networks will lead to increased capacity and improved service quality. For this purpose, in this article, a comprehensive review of the use of artificial intelligence in the field of satellite communications will be discussed. In the field of intelligent increase of capacity, various factors such as how to configure the network, how to allocate resources such as spectrum, energy and power will be investigated with consideration of intelligent interference management. Finally, in the field of service quality improvement, factors such as how to model and intelligently predict traffic, as well as how to deal with harmful environmental conditions, will be presented.
ResearchPaper
Space subsystems design: (navigation, control, structure and…)
Hamed R. Najafi; S.M.Hossein Karimian; Mohammad Reza Pakmanesh
Abstract
One of the passive components of the satellite Thermal control subsystem is multilayer insulation. In order to prevent air from being trapped between the multilayer insulation layers, which causes the thin layers to inflate and disintegrate during satellite launches, holes are made in the layers. These ...
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One of the passive components of the satellite Thermal control subsystem is multilayer insulation. In order to prevent air from being trapped between the multilayer insulation layers, which causes the thin layers to inflate and disintegrate during satellite launches, holes are made in the layers. These holes in different layers may not be aligned due to heat transfer problems as well as manufacturing constraints. For maximum thermal efficiency of thermal insulation, gas outlets must be designed to have the least resistance to exhaust gas flow, because the air trapped between the layers will greatly reduce the insulation efficiency by leaving a convective heat transfer path between them. In this article, different perforation matrix that have been used in articles are reviewed. By analyzing the computational fluid dynamics of gas outflow from these insulators, the effect of various parameters has been studied.
ResearchPaper
Space Ground Segment: receiving, transmitting, controlling and data processing
Roghayeh Doost; Saber Shahidzadseh; Roghieh Karimzadeh Baee; Pedram Hajipour
Abstract
Aeronautical-ESIM (A-ESIM) provides a satellite broadband service for aircraft occupants. Due to the frequency sharing of this service with previous services, there is a possibility of its frequency interference on previous services. According to the resolution WRC 2019, the A-ESIM frequency interference ...
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Aeronautical-ESIM (A-ESIM) provides a satellite broadband service for aircraft occupants. Due to the frequency sharing of this service with previous services, there is a possibility of its frequency interference on previous services. According to the resolution WRC 2019, the A-ESIM frequency interference on co-frequency ground stations must be prevented by observing the power flux density (PFD) mask . However, the approval of the PFD condition fulfillment method has been postponed to the WRC 2023. In this regard, some countries have simulated and determined the minimum allowable height of A-ESIM from the ground, so that the PFD reached the ground does not exceed the specified mask. In many cases, only limited positions of unauthorized heights will cause the PFD to override the mask. Therefore, in this paper, with a new solution, the authorized and unauthorized positions of A-ESIM are determined at any height less than the minimum allowable height, relative to a fixed ground station. In addition, the unauthorized positions of the A-ESIM in both take-off and landing positions are simulated and determined depending on the slope of the A-ESIM.
ResearchPaper
Space subsystems design: (navigation, control, structure and…)
Arash Abarghooei; Hassan Salarieh; Pedram Hosseiniakram
Abstract
Linear algorithms are the most widely used method for satellite attitude control using reaction wheels because of their simplicity and low computational cost. The first part of the paper introduces different attitude determination and control algorithms, and reviews resources that utilized optimal linear ...
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Linear algorithms are the most widely used method for satellite attitude control using reaction wheels because of their simplicity and low computational cost. The first part of the paper introduces different attitude determination and control algorithms, and reviews resources that utilized optimal linear and nonlinear control methods (such as LQR and SDRE). Next, dynamic equations for the control of the satellite using reaction wheels have been extracted, then the satellite controller has been designed by using optimal linear and nonlinear methods, which are robust against noise and disturbance, as an alternative for the PD controller. Finally, the designed control algorithms have been implemented for different satellite pointing scenarios, and by simulating these methods in MATLAB software, their performance has been studied and compared.
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