Space subsystems design: (navigation, control, structure and…)
Moslem Karim Abadeh; Morteza Tayefi
Articles in Press, Accepted Manuscript, Available Online from 09 April 2024
Abstract
In this study, the control of a space capsule during the re-entry phase is examined. Re-entry is one of the most important phases of a spacecraft's mission because when the spacecraft enters the Earth's atmosphere, aerodynamic forces and moments will disturb the angles of attack and side slip. These ...
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In this study, the control of a space capsule during the re-entry phase is examined. Re-entry is one of the most important phases of a spacecraft's mission because when the spacecraft enters the Earth's atmosphere, aerodynamic forces and moments will disturb the angles of attack and side slip. These disturb angles, if not controlled, can cause serious injuries to the spacecraft and its passengers. To eliminate the disturbances, moving mass controllers have been used as an operator. Moving mass controllers (MMC) control the flying device by creating an internal force. The main advantage of moving mass controllers compared to other operators such as aerodynamic surfaces and thrust jets is the non-production of turbulent aerodynamic force (which can disrupt the controller's performance) due to the creation of internal force. Another important factor is the mechanism of moving mass controllers. In this research, in addition to the cross mechanism, which is a more common mechanism, the radial mechanism has also been examined. A non-linear controller is needed in order to use the radial mechanism, and in this research, a non-linear proportional-integral-derivative controller is suggested.
Space subsystems design: (navigation, control, structure and…)
Morteza Tayefi; Ramin Kamali Moghadam
Volume 15, Issue 3 , September 2022, , Pages 1-9
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.
erfan beygi; Amirhossain Adami
Volume 11, Issue 4 , December 2018, , Pages 43-50
Abstract
Basically, it takes alot of time to analyze structures with different parameters, depending on the type of structure and parameters. Also, by changing any parameter, all the analysis process must be repeated. Therefore analyze the effect of different parameters on the behavior of structures, many analyzes ...
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Basically, it takes alot of time to analyze structures with different parameters, depending on the type of structure and parameters. Also, by changing any parameter, all the analysis process must be repeated. Therefore analyze the effect of different parameters on the behavior of structures, many analyzes should be carried out that are time consuming. The results obtained are valid only for the same parameters, and are not valid by changing the parameters. In this research, a Nested dependence method has been developed that can be used to determine the behavior of the structure with proper accuracy with short time. In this method, first an interval is considered for different parameters of the structure. Then, by using the finite element analysis method and applying the loading and boundary conditions, the behavior of the structure. By repeating this process to extract the appropriate number of input data, a Nested dependence method can be used to estimate the structure behavior of different inputs.
