Space subsystems design: (navigation, control, structure and…)
Fatemeh Asdaghpour; Fatemeh Sadeghikia; Mohammad Ali Farsi
Volume 15, Issue 2 , June 2022, , Pages 103-113
Abstract
Antennas, which are usually installed on the outer shell of these systems, are therefore always exposed to the thermal fluctuations of the space environment. Thermal fluctuations cause the antenna surfaces to expand, contract and distort and can cause the antenna to malfunction. In this paper, the effects ...
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Antennas, which are usually installed on the outer shell of these systems, are therefore always exposed to the thermal fluctuations of the space environment. Thermal fluctuations cause the antenna surfaces to expand, contract and distort and can cause the antenna to malfunction. In this paper, the effects of thermal expansion and contraction due to an LEO orbital mission on the radial characteristics of two X-band reflective antennas, one broadband antenna and the other narrowband, And the resulting radiation characteristics are compared with the characteristics of equivalent sample antennas at ambient temperature. Analyses show that narrowband antennas are very vulnerable to thermal fluctuations and, therefore, it is necessary to choose the material of the antennas from materials whose thermal expansion coefficient is very small. In addition, choosing the appropriate protection method to maintain the optimal performance of the antenna is one of the most essential activities in the construction of space antennas.
Nima Karimi; محمد علی فارسی
Volume 13, Issue 1 , March 2020, , Pages 13-23
Abstract
In the present paper, the process of designing launch abort system is presented for manned spacecraft in sub-orbital mission. For this purpose, by studying the other manned spacecraft launch abort system, a number of dimensionless parameters have been generated for the launch abort system and spacecraft. ...
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In the present paper, the process of designing launch abort system is presented for manned spacecraft in sub-orbital mission. For this purpose, by studying the other manned spacecraft launch abort system, a number of dimensionless parameters have been generated for the launch abort system and spacecraft. using these parameters, the mass, geometric-dimensional characteristics, the launch escape motor thrust and acceleration of the LAS have been estimated. Also The numerical aerodynamic analysis has been used to form the external configuration, and the results of the analysis, along with other effective parameters, have created a design framework. AHP analysis has been used to select the optimal configuration and in order to validation, an analytical model based on the momentum equation used to design the launch escape motor. Comparison of the results of this model and the statistical design has shown that the data produced is correct.
Mohammad Tahaye Abadi; Mehdi AlizadehYazdi; Mohammad Ali Farsi; Mohammad Ebrahimi
Volume 7, Issue 4 , January 2015, , Pages 51-62
Abstract
The paper concerns with the experimental analysis of the pyroshock wave propagation in the structure of Kavoshgar's payloadon the ground. The source of waves is the explosion of pyrotechnic materialacting as the actuator of separation mechanism for the payload subsystems. The shock sensors are attached ...
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The paper concerns with the experimental analysis of the pyroshock wave propagation in the structure of Kavoshgar's payloadon the ground. The source of waves is the explosion of pyrotechnic materialacting as the actuator of separation mechanism for the payload subsystems. The shock sensors are attached in different locations of structure to measure the acceleration amplitude along three orthogonal directions after the activation of pyrotechnic material.The experimental setup is used for measurement of the acceleration history as well as the evaluation of the shock response spectrum at specific locations during two-stage separation of payload subsystems. The experimental acceleration record is evaluated to eliminate the noise signals and incorrect data. The variations of shock  response at different payload locations are evaluated to determine the amplitude attenuation of the wave passing through the structure body and joints. The measured data are also employed to determine the working condition and design criteria for the equipment of Kavoshgar payload.
F. RasiMarzabadi; R. Meshkani; H. Pouryavi; M. A. Farsi; M. Ebrahimi
Volume 7, Issue 2 , July 2014, , Pages 23-33
Abstract
According to the importance of knowing aerodynamic parameters of parachutes used as recovery system of a sounding rocket, some launching tests were conducted to achieve the acceptable reliability. A testing rocket which simulated the recovery condition of the sounding rocket was used in these tests. ...
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According to the importance of knowing aerodynamic parameters of parachutes used as recovery system of a sounding rocket, some launching tests were conducted to achieve the acceptable reliability. A testing rocket which simulated the recovery condition of the sounding rocket was used in these tests. Furthermore, the results of the tests used for validating a simulation code written for investigating the aforementioned two stage recovery system process. Some aerodynamic parameters of parachutes such as drag coefficient, opening force coefficient, and filling time, filling distance and drag area increase during inflation process were estimated from the tests in various conditions. The results show that for the first and second used drogue chutes with large canopy-loading, in contrast to the main parachute with small canopy-loading, the inflation parameters were not dependent on the height or air density. The drag area versus time shows linear variation for the first drogue chute, and shows second and third function for the other two parachutes. The situation of the second drogue chute in front of the main parachute affects the filling time of the main parachute. The distance between the parachutes, the ratio of their canopy areas and the air velocity are some parameters that affect the filling time. The results of this investigation could be worth for the design of a decelerator system, preciously.
M. A. Farsi; A. A. Eslami; R. Gorgin
Volume 7, Issue 1 , April 2014, , Pages 25-31
Abstract
Separation system is one of the most important systems in rockets. The influence of this system on mission success cannot be ignored. In this paper, reliability of a sounding rocket separation system is determined using block diagram and FMEA . This system is based on the flexible linear shape charge ...
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Separation system is one of the most important systems in rockets. The influence of this system on mission success cannot be ignored. In this paper, reliability of a sounding rocket separation system is determined using block diagram and FMEA . This system is based on the flexible linear shape charge cross-section and a spring mechanism to accelerate separation. In this investigation, the reliability block diagram of the separation system including mechanical and electrical mechanisms is determined. By considering reliability of each component based on expert opinion and using separation system reliability block diagram, reliability of separation system is determined. Moreover, since spring mechanism is one of the most important parts of separation system, a complete FMEA analysis is conducted for this mechanism. According to this analysis, piston, cylinder, pin, and springs have the highest RPN number. Hence, these parts must have a high reliability. On the other hand, results are shown that bracket and bush have the lowest RPN number; therefore, it is not important for these parts to have a high reliability.
M. A. Farsi; N. Ariaii-Far; R. Kalantari-Nezhad; M. Bahrami
Volume 3, Issue 1 , July 2010, , Pages 15-23
Abstract
Separation system is one of the main sub-systems in every space device and missile. This system is used to separate active and inactive sections in a missile. The separation process should be done accurately. A separation system explained in this paper was designed and produced based on mission, rocket ...
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Separation system is one of the main sub-systems in every space device and missile. This system is used to separate active and inactive sections in a missile. The separation process should be done accurately. A separation system explained in this paper was designed and produced based on mission, rocket configuration and manufacturability. This system uses explosive bolts and spring mechanism. This separates accurately payload from motor in a sounding rocket. Aerodynamic forces were used to determine structure strength. This structure designed based on at least weight and drag force. Several tests were done to evaluate this system performance. The tests results confirm this
system capability.
