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This paper addresses the staging optimization problem for multistage rockets which carry payloads from the Earth's surface into the Earth orbits. In the early design phases, requirements are not so strict, there are many unknowns and problem arises as to what is the optimum staging to achieve the given mission. Therefore, designers need simplified tools providing a quick insight on the vehicle performance...
As a part of the ORVEAL project, the design of the new compound rocket engine MEC-80MIA and MEC-80JMIC is subjected to a line of restrictions imposed by the experiment plan, which ad an extra weight to the definitely expensive phase of the experimental development of the new compound rocket engine. The direct way to reduce the time and cost of development was found in tediously defining the experimental...
There is no doubt that the selection methodology and appropriate technology is required for any problem solving. It relates for environmental issues in power energy transmission.
Conceived as simple, cheap and highly efficient alternative to solid rocket motors, the compound rocket engines include a liquid feed line system, within which at least the minimal components are involved, like the liquid tank, the dislocation augmenter, the main release valve, the in-line check valve (ICV) and the injector head. Simplicity and reliability are the main requirements in designing and...
The paper purpose is to dignify some aspects regarding the calculus model and technical solutions for multistage suborbital launcher for testing (SLT) used to test spatial equipment and scientific measurements. The calculus methodology consists in numerical simulation of SLT evolution for different start conditions. The launcher model presented will be with six DOF and variable mass. At this item,...
Carbon fiber reinforced plastic (CFRP) composite shell reflectors have been developed for space borne antennas due to their light weight, high thermal stability, and high surface accuracy. In order to reduce launch cost and structural mass, compactly folding and self-deployment of the reflector is preferred. In this paper, the full-scale offset reflector with a diameter of 6 m was designed by introducing...
The Aim of this paper is to verify which modulator will extend the life time of a spacecraft attitude control system utilizing thrusters. For this purpose, the optimal region of operation for Pulse Width-Pulse Frequency modulator and Pseudo-Rate modulator is defined where they are used as a compensator in the control subsystem. The optimal region is where the modulator behavior is close to linear...
This paper presents the technique and results of Single Event Upsets fault injection in the configuration bit-stream of SRAM-based FPGAs through partial reconfiguration of configuration frames. The Xilinx Virtex5 LX50 is used in the experiments. The Single Event Upset controller macro is used injecting faults to random locations of the FPGA bit-stream. The effects were studied on a design consisting...
This paper focuses on evaluating three main design criteria including efficiency, reliability and cost for different topology schemes of Electrical Power Subsystem (EPS) of a satellite in Low Earth Orbit. Selecting an appropriate topology may increase the overall EPS efficiency and extend the lifetime of satellites. In this article, ten basic EPS topologies are studied, evaluated and compared. In...
The engineering structures may be subjected to the dynamic loads such as blast. Therefore, in the design of such structures, the effect of the blast loading should be taken into account. Several studies are reported on both free vibration and dynamic response analysis of isotropic, orthotropic and laminated composite plates subjected to air blast loading. In all these studies, only the effect of the...
In the present paper, we have introduced a model for statistical designing a subsystem for communication in satellites. The most prominent aspects of this work are its accuracy, which is more than 96%, and the high rate of design. It should be mentioned that we have employed some statistical software programs such as SPSS in analyzing the collected data bank information. The model evaluation has been...
The satellite remote sensing missions are essential for long-term research around the condition of the earth resources and environment. On the other hand, in recent years the application of microsatellites is of interest in many space programs for their less cost and response time. In microsatellite remote sensing missions there are tight interrelations between different requirements such as orbital...
In spacecraft technologies electric propulsion is a well-suited option to meet the in-space propulsion requirements of both near-Earth and deep space missions, promising more affordable and sustainable solutions. Savings in propellant mass and launch costs, and longer lifetime and higher specific impulse make electric propulsion systems more attractive than the chemical counterparts for commercial...
Forest detection and classification in tropical regions is very important for climate change research. Combining available data from different sensors is widely used in remote sensing to improve detection and classification performance. In this study, a decision fusion strategy is proposed to integrate optical and multifrequency PolSAR data for classification of rural areas including forest. Developed...
Spaceborne membrane phased array is prone to distortion due to lack of mechanical rigidity. Distortion introduces phase errors between array elements which will significantly degrade antenna performance such as directivity and sidelobe level. An innovative self-calibration method was invented to compensate phase errors with minimum equipment involved. Using the un-calibrated array itself to transmit...
Selection of stable point wise targets is an important procedure in multi-temporal SAR images interpretation and application in monitoring surface deformation. Several targets selection methods based on amplitude and coherence approaches have been proposed in recently years. However, these two approaches have their own defects. Amplitude Selection (AS) method require enough data to ensure the accuracy...
In this study, gyroscope-free inertial measurement unit interface is developed to simulate new system configurations called YILDIZ using known calculation methods and implementation of MEMs accelerometers based on cubic arrangement. Additionally significant effect of different sensing directions and sensor allocations are taken into consideration. Throughout the project, simulation studies, realization...
To support focused science and engineering missions, spacecraft bus designs should minimize mass and maximize design flexibility without reducing capability. This requires a highly efficient spacecraft structure to maintain the required stiffness with a minimal mass.
Doppler centroid frequency is an important parameter for Synthetic Aperture Radar signal processing, which is used to design a proper matched filter in azimuth domain. Doppler centroid is estimated from the received data. There are number of different algorithms for the Doppler centroid estimation presented in the literature. In all these algorithms, a general the Doppler centroid estimation is done...
As part of the attitude determination system on board microsatellites, the kalman filter is implemented to generate an estimate attitude upon sensor observation. This paper presents an overview and analysis of the attitude estimator based on Kalman filtering for application on low Earth orbit microsatellites, specifically, Alsat-1 first Algerian microsatellite was used as an example. Various steps...
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