Space systems design (spacecraft, satellites, space stations and their equipment)
Hojat Taei; Mahmood Haghighat Esfahani; Sajjad Yadegari Dehkordi
Volume 14, Issue 3 , September 2021, , Pages 39-50
Abstract
In this paper, a novel Comprehensive Preference-based Design (CPD) approach is presented which attempts to achieve subjective attributes that are defined in the concept of maximization of designer/customer's satisfaction in addition to objective goals which are formulated in the form of minimization ...
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In this paper, a novel Comprehensive Preference-based Design (CPD) approach is presented which attempts to achieve subjective attributes that are defined in the concept of maximization of designer/customer's satisfaction in addition to objective goals which are formulated in the form of minimization of a performance criterion in a two-phase structure using two nested optimizers.In the first phase of CPD,using the concept of satisfaction,the subjective preferences of the designer/customer are defined in terms of fuzzy relationships and operators.Whereas the results of this phase are inaccurate,in the second phase,it is attempted to define a performance criterion and in order to achieve an optimal operational plan,attitude parameters and the compromises needed to meet the designer/customer's preferences are implemented.The methodology is utilized to design of a space launch vehicle for delivering 1200 kg payload to a 750 km orbit.Comparison of the results shows that despite the higher mass of launch vehicle designed by CPD,overall design satisfaction is higher and designer/customer's preferences have been satisfied.
Mohmmad Goharkhah; Mostafa Esmaeili; Mehdi Ashjaee
Volume 11, Issue 2 , September 2018, , Pages 11-19
Abstract
In this paper, the effect of an external non-uniform magnetic field on forced convective heat transfer of magnetite nanofluid (ferrofluid) in a heated channel is studied numerically. The main goal is to emphasize the importance of magnetic field location and investigate the possibility of heat transfer ...
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In this paper, the effect of an external non-uniform magnetic field on forced convective heat transfer of magnetite nanofluid (ferrofluid) in a heated channel is studied numerically. The main goal is to emphasize the importance of magnetic field location and investigate the possibility of heat transfer enhancement by finding the optimum location of magnetic field source.It is observed that the magnetic field results in creation of recirculation zones which affect the thermal boundary layer thickness and Nusselt number. Results show that the effect of magnetic field location on the heat transfer is completely dependent on the thermal boundary condition. It is also shown that the flow and temperature fields can be manipulated by application of multiple magnetic field sources. Using genetic algorithm (GA), an optimum arrangement for locations of eight magnetic field sources is obtainedresulting in a27% heat transfer enhancement compared to the case of no magnetic field.
Maryam Kiani; Amir Shakouri; S.H Pourtakdoust; Mohammad Sayanjali
Volume 11, Issue 1 , June 2018, , Pages 49-57
Abstract
A new strategy is presented for the optimal transfer of non-coplanar elliptical orbits based on sequential multi-Lambert trajectories. The proposed method tries to minimize the control effort during the orbit transfer. The main advantages of the proposed method include transfer between arbitrary initial ...
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A new strategy is presented for the optimal transfer of non-coplanar elliptical orbits based on sequential multi-Lambert trajectories. The proposed method tries to minimize the control effort during the orbit transfer. The main advantages of the proposed method include transfer between arbitrary initial and final orbits, utilizing desired number of impulses, and covering all possible transfer trajectories to achieve the target. The position and time instant of impulses are considered as the design variables which determine utilizing the well-known optimization method of pseudo-Newton. Performance of the proposed method is investigated and verified through some numerical simulations. It is also shown that the proposed method converges to the celebrated Hahmann’s maneuver in transfer between two coplanar orbital orbits.
Asad Saghari; Hadi Veysi; AmirReza Kosari
Volume 9, Issue 3 , December 2016, , Pages 27-36
Abstract
Orbital parameters are raised as one of the main inputs of electrical power subsystem and thermal control subsystem of a satellite. Some variables such as eclipse time, sun incidence angle to the panels, albedo and thermal radiation of Earth are dependent on satellite orbital features. In this paper, ...
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Orbital parameters are raised as one of the main inputs of electrical power subsystem and thermal control subsystem of a satellite. Some variables such as eclipse time, sun incidence angle to the panels, albedo and thermal radiation of Earth are dependent on satellite orbital features. In this paper, all of the parameters above are simulated using precise simulation methods within the satellite mission. That is, the process of optimal orbital design is performed with the aid of evolutionary optimization methods. This process is aimed at minimizing number of mission days that misses the assurance of satellite power supply in addition to minimizing thermal load exerted to satellite and also its standard deviation. At last, a pair of optimal solutions for two different configurations is compared.
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.
R. Zardashti; A. A. Nikkhah
Volume 2, Issue 3 , December 2009, , Pages 13-17
Abstract
In this paper, Design of flight trajectory in unpowered phase namely “Coast Phase” which is important in energy reduction in transition orbit of spacecrafts and launch vehicles is considered. To this aim, the velocity impulse at both sides of the transition phase (between initial and final ...
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In this paper, Design of flight trajectory in unpowered phase namely “Coast Phase” which is important in energy reduction in transition orbit of spacecrafts and launch vehicles is considered. To this aim, the velocity impulse at both sides of the transition phase (between initial and final orbits) is described as a parametric function of the geometry of the path. Then the optimal coasting trajectory is proposed using simple minimization techniques like Fibonacci Search Method and a Velocity-Required Based Steering technique simultaneously. A numerical study is performed using a three stage launch vehicle with a coast phase between second and third stages to show that the proposed technique is capable to produce optimum transition trajectory and since it is accompanied by guidance technique could be used as an online technique.
M. Mirshams; H. Karimi; H. Naseh
Volume 1, Issue 2 , December 2008, , Pages 17-25
Abstract
The principle goal of this paper is to introduce Launch Vehicle Conceptual Design (LVCD) software based on multi-parameter optimization idea. The main objectives of this software arereduction of the cost and time of conceptual design phase. This software is user friendly such that an operator familiar ...
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The principle goal of this paper is to introduce Launch Vehicle Conceptual Design (LVCD) software based on multi-parameter optimization idea. The main objectives of this software arereduction of the cost and time of conceptual design phase. This software is user friendly such that an operator familiar with fundamentals of design and launch vehicle mass – energy equations and with primary training operator is capable to work with LVCD.The algorithm used in LVCD, is based on combinational optimization of major design parameters. To this end, ten sub-algorithms will be presented in this design approach. Mass distribution of different stages to launch maximum payload mass to the orbit, pitch program trajectory to get to the maximum final velocity, and providing minimum velocity loss due to gravity, and also minimum axial acceleration of various stages of launch vehicle will be optimized as the results of the presented approach. The optimization process is performed subject to the restrictions. Also, the performance index is optimized in a mutual iteration mechanism (multi-parameter optimization). Evaluation and verification of the presented method is performed using available data of two and three-stage launch vehicles.
M. Mirshams; H. Karimi; H. Naseh
Volume 1, Issue 1 , September 2008, , Pages 21-36
Abstract
The principle goal of this paper is developing of Launch Vehicle Conceptual Design (LVCD) method based on combinational optimization of major design parameters. To this end, ten sub-algorithms will be presented in this design approach. Mass distribution of different stages to launch maximum payload mass ...
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The principle goal of this paper is developing of Launch Vehicle Conceptual Design (LVCD) method based on combinational optimization of major design parameters. To this end, ten sub-algorithms will be presented in this design approach. Mass distribution of different stages to launch maximum payload mass to the orbit, pitch program trajectory to get to the maximum final velocity, and providing minimum velocity loss due to gravity, and also minimum axial acceleration of various stages of launch vehicle will be optimized as the results of the presented approach. The optimization process is performed subject to the restrictions. Also, the performance index is optimized in a mutual iteration mechanism. Evaluation and verification of the presented method is performed using available data of two and three-stage launch vehicles.
