investigating space radiation
Hamideh Daneshvar; Masoud Khoshsima; Abolfazl Dayyani
Volume 12, Issue 3 , September 2019, , Pages 63-71
Abstract
One of the important issues to be considered in the design of space systems is the attention to the difference between the terrestrial and space environment. This issue changes the design and affects all subsystems of space systems. Radiation damage due to space radiation can cause disturbances in the ...
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One of the important issues to be considered in the design of space systems is the attention to the difference between the terrestrial and space environment. This issue changes the design and affects all subsystems of space systems. Radiation damage due to space radiation can cause disturbances in the functioning of space systems. In this paper, with a computational approach examines the most important radiation damage involving TID, DD and SEU in two satellites that have missions in LEO orbit. The calculations were performed using the OMERE software and finally, a comparison was made between different models for achieving different types of radiation damage.
Seyed Mohammad Sadegh Mosvi; Mehdi Mortazavi
Volume 9, Issue 2 , September 2016, , Pages 11-24
Abstract
In order to be sure from true function of satellite’s Attitude determination and Control Subsystem (ADCS) and its parts, some tests are needed to be done in part or subsystem level. One of the useful tools for doing these tests is Helmholtz Coil. This tool is usable in functional tests and calibration ...
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In order to be sure from true function of satellite’s Attitude determination and Control Subsystem (ADCS) and its parts, some tests are needed to be done in part or subsystem level. One of the useful tools for doing these tests is Helmholtz Coil. This tool is usable in functional tests and calibration of satellite’s magnetic sensors and actuators, in Hardware In the Loop (HIL) tests of ADCS subsystem, and also in related tests to residual magnetic of satellite’s part. In this paper, we study mathematical equations of Helmholtz coil, propose design procedure and requirements, also introduce set of functional and identification tests for evaluating the constructed Helmholtz Coil. By obtaining results and finding the mathematical model of Helmholtz Coil, preparations for designing closed loop control system to eliminate environmental magnetic disturbances and create desired magnetic field by Helmholtz coil are provided.
M. Shafiey Dehaj; R. Ebrahimi; H. Karimi; A. Jalali; M. Naderi
Volume 6, Issue 4 , January 2014, , Pages 1-11
Abstract
The effects of liquid propellant rocket engines thrust termination transients are important in achieving the launch vehicle’s desired final velocity with the required precision. In this paper, a mathematical model has been developed to predict the changes in the combustion chamber pressure and ...
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The effects of liquid propellant rocket engines thrust termination transients are important in achieving the launch vehicle’s desired final velocity with the required precision. In this paper, a mathematical model has been developed to predict the changes in the combustion chamber pressure and the related cut-off impulse based on the physical aspects of engine’s components. The modeling is divided into four steps: (1) from issuing the cut-off command to the activation of valve (2) from the time of executing the stop command until the end of the operation of the cut-off valves, (3)from the time that after the valve is shutt closed until the combustion chamber is extinguished and (4) simulation of the phase change and propellant components evaporation in corrugates. Results suggest that the duration of the first two steps have a significant effect on increasing or decreasing the amount of the thrust force and the 4th step’s thrust is less than 10 percent of nominal value while, the most thrust fluctuations appear in this step.
