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Capacity building in space engineering is vital process to space development at both the national and international levels. Long term sustainability is also vital to the future space activities. This is a key theme of the discussions in global space forums such as UNCOPUOS. The issue of increasing density of debris in orbit is very relevant to nano-satellite activities at university level. The University...
Active structural health monitoring methods are becoming increasingly popular for defect detection in hollow cylindrical structures utilized in aerospace applications. Electro mechanical impedance (EMI) based methods are commonly used to study the health of hollow cylinders in broad frequency ranges. However, the EMI analyzers are bulky and costly. In addition, EMI based methods require high quantity...
Temperature constantly changing across space hence low and high temperature occurs on geostationary orbit (GEO) communication satellites by the impact of environmental heat loads. Thus, the thermal control analysis becomes very important fact to protect GEO satellites from the space environmental effects throughout launch and lifetime. In this study, the numerical models will be shown by thermal analysis...
The present work is devoted to one of the methods of protecting the Earth from asteroid's danger, namely, the use of the gravitational space tug. A 3D mathematical model of control movement asteroid, space tug and Earth taking into account the gravity perturbation from all bodies including in system and the real position of celestial bodies. A software package the simulation and visualization of the...
In this paper, fault-tolerant active control of the rotational motion of the satellite has been applied. Satellite mathematical models are introduced, and the nontraditional Kalman filter is designed with the presented control algorithms. Re-adjustment control procedure has been established taking into account the identified control distribution matrix. If there are three-axis reaction wheels on the...
Lossless compression is an important topic in ultraspectral sounder data which includes thousands of spectral channels and it needs to store or transmit data in an efficient form. In this paper, a recursive least squares (RLS) based prediction method is proposed for the lossless compression of ultraspectral data. Experiments are performed on 10 granule maps which are acquired by NASA's Atmospheric...
This paper describes singular value decomposition (SVD) aided extended Kalman filter (EKF) for nanosatellite's attitude estimation. The development of the filter kinematic/dynamic model, and the measurement models of the sun sensors, and the magnetometers which are used to generate vector measurements is presented. Vector measurements are used in SVD for satellite attitude determination purpose. In...
The inertia parameters information has an important role to ensure the success of the attitude control during satellite mission. However, in practical situations, the inertia of satellites can be changed due to the fuel consumption, the onboard motion and the rotation of solar arrays. And it is also difficult to be accurately determinated on ground because of the complexity of the satellite geometries...
Robust design methodology is concerned with the process and the product design while minimizing the effects of uncertainties in design and external noises. In robust design, optimum system design is sought with special emphasis on the insensitiveness of objective functions due to uncertainties. This study focuses on the robust design studies of vibration and shock isolation of sensitive electronic...
The research on the small satellites is on the rise since last two decades thanks to the use of low cost design solutions which have significantly reduced the cost of the space missions. The attitude determination and control subsystem (ADCS) is a core subsystem in order to stabilize and orient their position in space. Magnetometers and magnetic torque actuators are an integral part of ADCS subsystem...
This article presents the in-flight ground sampling distance (GSD) estimation of the Alsat-1 Slim-6 imager. There are several methods to evaluate the imager GSD, based on natural and/or artificial targets (geometric shapes). We used an image from a higher resolution satellite which was considered as a reference image. This method is based on the error minimization between the two images: Alsat-1 and...
Satellite simulators for Synthetic Aperture Radar (SAR) can be categorized into two main classes according to its functional use: System Engineering Simulator or Mission Simulator. A system engineering simulator provides a high fidelity infrastructure for SAR system designers to determine or adjust the parameters of the system to realize the requirements. A Mission Simulator behaves as the whole system...
Monopulse radar provides information about the angular position of the target by comparing signals received from simultaneous beams. Compared to conventional radar systems, monopulse radars are not affected by amplitude fluctuations to obtain angle error voltage due to single pulse used. Cross polarization jamming technique is one of the most commonly used electronic counter measures against monopulse...
Digital elevation model (DEM) is primarily a way of visualising 2D maps, photographs and images in 3D. Common uses of DEMs are creation of relief maps, rendering of 3D visualizations, rectification of satellites images and aerial photographs, creation of different physical models, etc. DEMs can be produced by different methods. In this study, DEMs are produced by 1:25000 digital topographic maps,...
Recent technological advances in satellite miniaturization, directed efforts in earth observation towards microsatellite constellations. Ultimate goals of Earth observation satellite missions are having maximum number of images with high quality and maximum orbital performance such as maximum coverage and minimum revisit time. These goals can be achieved by microsatellite constellations. In this study,...
Inventory management is in the heart of operational performance in aircraft parts and space vehicles industries. As a result of its importance in practice, this subject has been extensively studied in recent years in operations management. The main focus of this study is to look at the relationship between inventory management performance such as inventory effectiveness, efficiency and responsiveness...
In this study, the conceptual design of a single-stage hybrid rocket engine of a low-altitude sounding rocket is developed using the Multi-Objective Vibrational Genetic Algorithm (MOVGA). A hybrid rocket engine design having single circular port fuel grain with constant cross-section doped with oxidizer is done. Hybrid rocket engine is fueled by Hydroxyl-Terminated Polybutadiene (HTPB) with oxygen...
This paper describes a method to calculate the optimal impulsive maneuver to avoid the collisions using Simplified General Perturbation 4 (SGP4) and Two Line Element (TLE). It also presents a rigorous analysis of the method to investigate the relative dynamics of the two colliding space objects assuming the encounter is instantaneous. Different collision geometries are used for test cases. For all...
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