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
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 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
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; Farhad Fanisaberi; 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…)
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 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
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 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.
ResearchPaper
Space Science and Technology
Hossein Mahdavy-Moghaddam; Vahid Rahimi Goradel
Abstract
Each missile has a payload section and an engine section. In the path of the missile, there is a time when the mission of the engine section is over and after that the engine will not play an effective role and will be as extra weight and consequently reduced range or factor for easy detection of the ...
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Each missile has a payload section and an engine section. In the path of the missile, there is a time when the mission of the engine section is over and after that the engine will not play an effective role and will be as extra weight and consequently reduced range or factor for easy detection of the warhead by enemy agents. In such a situation, after completing the engine mission, the mechanism of separating the steps and separating the head from the body is used. One of the separation methods is to use the thrust termination system method. In this paper, with the studies performed on the thrust termination system and the presentation of mathematical relations, the pressure drop and inverse thrust created in the chamber after opening the reverse thrust valves are predicted. Also, cold type separation and thrust termination system were used and the combustion chamber pressure drop is simulated. Then, the effect of important and influential factors on the thrust termination system has been investigated.
ResearchPaper
investigating space radiation
Sara Shoorian; S. Amir Hosein Feghhi; Hamid Jafari; Reza Amjadifard
Abstract
Protection of astronauts and electronic components in satellites and spacecraft against space rays is one of the most important primary requirements in space missions. In this work, the effect of three materials, aluminum, as the most common material, polyethylene and a graded-z structure, in the protection ...
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Protection of astronauts and electronic components in satellites and spacecraft against space rays is one of the most important primary requirements in space missions. In this work, the effect of three materials, aluminum, as the most common material, polyethylene and a graded-z structure, in the protection of space radiations has been evaluated. The calculations of the dose caused by these radiations on the human body and a silicon piece have been carried out by MCNPX Monte Carlo code,. The dose caused by cosmic rays has been calculated after applying shields of aluminum, graded-z structure and polyethylene. The results showed that by using polyethylene and about 4.4% increase in weight compared to the aluminum shield, it is possible to reduce the dose caused by photons by more than 50% in the human body and 30% in silicon parts, and the dose caused by protons by about 30%. It cut both for astronauts and electronic components. Graded-z shielding performed very well in the dose attenuation caused by photons, but appeared ineffective in the dose attenuation caused by protons.
ResearchPaper
physiology and space medicine (astrobiology)
Abstract
Light is a vital factor for plant cultivation. LED lamps in different spectra have some advantages such as low heat production and energy requirement, and long lifespan, which was used for the first time to design plant growth chambers in closed culture systems and space research. In this research, impact ...
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Light is a vital factor for plant cultivation. LED lamps in different spectra have some advantages such as low heat production and energy requirement, and long lifespan, which was used for the first time to design plant growth chambers in closed culture systems and space research. In this research, impact of light spectrums was studied on the growth mechanisms through chlorophyll pigments, enzyme defense system, and antioxidant metabolite analyses. Seeds were cultivated in Murashige and Skoog medium and exposed to different light spectrums of white, red, blue, and red-blue. Then the seedlings were harvested for growth and biochemical analyses after 4 weeks. Results showed that red-blue and blue lights induced the fresh weight, dry weight, root length, adventitious roots, chlorophyll content, protein, flavonoids and antioxidant enzymes of superoxide dismutase and catalase. Blue spectrum significantly decreased stem length and increased the relative water content. Moreover, the highest amount of hydrogen peroxide was observed in seedlings treated with red light. It seems that light spectra by changing the hydrogen peroxide level can regulate antioxidant enzyme activity and enhance antioxidant metabolites, and red-blue light may use as a suitable lighting spectrum for the design of M. chamomilla cultivation chamber in space research.
ResearchPaper
investigating space radiation
gholamreza raisali; masume soleimaninia; Amir Moslehi
Abstract
In this paper, the sensitive volume and critical charge of a 65-nm CMOS SRAM as two important quantities in Single Event Upset (SEU) calculations have been determined. SEU is the most common event in space investigations. To this purpose, a memory cell which is consisted of NMOS and PMOS was simulated ...
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In this paper, the sensitive volume and critical charge of a 65-nm CMOS SRAM as two important quantities in Single Event Upset (SEU) calculations have been determined. SEU is the most common event in space investigations. To this purpose, a memory cell which is consisted of NMOS and PMOS was simulated using Silvaco TCAD tool. Then, the variations in output voltages were studied after striking incident particles with different values of Linear Energy Transfer (LET) at different regions of the transistors. The Qcritical was obtained by integrating the output current when the output voltages were inverted. To determine the sensitive volume, the minimum amount of LET in which the output logic state of the memory cell flips, was considered as a criteria of sensitivity. The results showed the value of 0.054 µm3 and 1.48 fC for sensitive volume and critical charge, respectively which are in good agreement with the references.
ResearchPaper
investigating space radiation
Pedram Hajipour; Leila mohammadi; Azam Eidi; Sara Shoorian; Nahid Eidi esfiani; Seyed Amir Hossein Feghhi
Abstract
One of the damaging factors for the proper functioning of telecommunication payloads are high energy ionizing particles in space, which the use of proper shield is a way to deal with it. In the design of protection, several factors, such as the type of part and the amount of weight acceptable for the ...
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One of the damaging factors for the proper functioning of telecommunication payloads are high energy ionizing particles in space, which the use of proper shield is a way to deal with it. In the design of protection, several factors, such as the type of part and the amount of weight acceptable for the payload.etc.must be taken into consideration. In recent years, in order to reduce the costs of construction and launch, the use of non-space components has been favored.Therefore, the use of shields with the suitable material in with radiation resistance, with respect to the weight budget considerations, will be one of the important challenges .In this paper, the aim is to investigate the methods of reducing the weight budget considering with respect to the radiation damage of ionizing dose. In this regard, a five-year technology development mission in the GEO orbit has been predicted, and the results of simulations and testing of aluminum and polyethylene shielding to check ionizing dose damage, according to the initial and reference weight budget, have been presented and compared. The analysis and evaluation of the test results using polyethylene protection shows a 17.21 percentage reduction between the two external and internal radiation meters.
