Day 1 :
- Satellite and its applications | Aerospace and Mechanical Engineering | Communications Satellite
Location: Webinar
Session Introduction
Aravind Gundakaram
Mahindra University, India
Title: Mathematical modelling and numerical solution for high precision satellite ephemeris determination
Biography:
Aravind Gundakaram is a student of Mahindra University pursuing his bachelor’s degree in Computation and Mathematics. His understanding of the mathematical model together with the implementation skills of his team allow them to come up with high precision mathematical models and also effective implementations for the said models. The current satellite orbit propagator presented in the said paper, namely the Satellite Ephemeris Determiner (SED) is the result of over two years of consistent work from the entire team, and guidance from several people working in the industry. The mathematical model in this paper has been built of after a thorough review of existing orbit propagator models and the results obtained from them. Moreover, the very high cost of the popular High Precision Orbit Propagator (HPOP) served as further motivation for the team to develop their own propagator SED, that is equivalent to HPOP. In the future, the team aims to make further advancements in the field and enhance SED to handle the three-body problem as well, so that it can outperform HPOP.
Abstract:
In this paper, we develop a high precision satellite orbit determination model for satellites orbiting the Earth. Solving this model entails numerically integrating the differential equation of motion governing a two-body system, for which we employ Fehlberg’s formulation of the Runge-Kutta class of numerical integrators with adaptive stepsize control. Various perturbing forces are also accounted for in the mathematical model, such as the acceleration due to the geopotential of the Earth, third-body gravitational effects, solar radiation pressure and atmospheric drag. For applications requiring high precision modelling, we also account for Earth radiation pressure, the perturbative effects of solid-Earth tides and ocean tides, and also make adjustments to the total acceleration for relativistic effects.
We have provided explicit expressions to calculate the force exerted by each perturbation that contributes to the total acceleration of the satellite. In situations where calculating certain terms in these expressions poses practical challenges, we have provided recurrence relations to assist with implementation. The implementation of this model yields a satellite orbit propagator, which we call the Satellite Orbit Determiner (SED). We have discussed the architecture of SED and the methodology it employs, and have presented the numerical results obtained from it. These results are compared with the widely used High Precision Orbit Propagator (HPOP). Currently, SED has only been implemented for the two-body problem, but future advancements will enable it to handle the three-body problem as well.
Biography:
Abstract:
Statement of the Problem: Scientists study gyroscopic effects without success for over 300 years. Only famous L. Euler derived a mathematical model for the precession torque that does not explain other gyroscopic effects. Recent studies demonstrated; the physics of gyroscopic effects are more sophisticated than contemplated by researchers. Methodology & Theoretical Orientation: The external torque acting on the spinning objects generates the system of inertial torques with the feedback system and interrelated motions around axes presented in the coordinate system (Fig. 1)) where the external torque (bold line), the inertial torques (thin line), and the angular velocities of the disc (contour line). The action of the torques and interrelated motions of the spinning disc was defined by the method of causal investigatory dependency. Findings: The inertial torques acting around axes are produced by four centrifugal and two Coriolis forces and the two changes in the angular momentum are generated by the rotating mass of the spinning disc. The action of the inertial torques generates interrelated motions of the spinning disc around axes. Conclusion & Significance: The system of torques and interrelated motions of the spinning disc around axes make up the fundamental principles of the theory of gyroscopic effects for rotating objects based on the mechanical energy conservation law. These fundamental principles open a new chapter in the dynamics of rotating objects in classical mechanics that should be presented in all publications of physics mechanics.
Paul Szymanski
president at Space Strategies Center (SSC), Albuquerque, New Mexico
Title: Space Warfare Military Assessments
Biography:
Abstract:
The importance of space to modern battlefields is unquestioned. However, due to the newness of space warfare, and the tremendous distances involved, it is very difficult to assess adversary goals and intents expressed by their military actions in space. To help solve these critical issues, the author, based on his 49 years’ experience in space warfare, has analyzed actual space wars that have already occurred. He will brief basic principles of outer space warfare and its history (there have been at least 10 space wars or incidents since the 1970’s), and provide a detailed example of the space war that occurred in 2014 and what has occurred in space this year over the current Ukrainian conflict. He will also demonstrate an orbital simulation that mathematically proves the attack on Russian Glonass satellites in 2014.
Aboozar Aghaei
Hirbodan Management Company
Title: Fatigue behavior of dissimilar welded Monel400 and SS316 by FSW
Biography:
Aboozar Aghaei is from Hirodan Management Company. He attended so many conferences.
Abstract:
Christopher Adeogun
Mountain Top University, Ogun State, Nigeria
Title: Space Satellites Using Solar Energy and Microwave Wireless Transmission Technology
Time : 13:30 - 14:00
Biography:
Christopher O. Adeogun is from Mountain Top University, Ogun State, Nigeria. He has attended too many Conferences
Abstract:
Solar Power Satellites (SPS) converts solar energy in to micro waves and sends that microwaves in to a beam to a receiving antenna on the Earth for conversion to ordinary Electricity. SPS is a clean, large-scale, stable electric power source. For SPS Wireless power transmission is essential. WPT contains microwave beam, which can be directed to any desired location on Earth surface.
Shabadini Sampath
University of Strathclyde
Title: Intelligent and Robust Control of Space Manipulator for Active Removal of Space Debris
Biography:
Abstract:
With huge kinetic energy, space debris poses a major threat to astronauts’ space activities and spacecraft in orbit if a collision happens. The active removal of space debris is required in order to avoid frequent collisions that would occur. During the process of capturing and deorbiting space debris, the space manipulator has to achieve high control precision. However, due to uncertainties and unknown disturbances, there is difficulty in coordinating the control of the space manipulator. To address this challenge, this paper focuses on developing a robust and intelligent control algorithm that controls joint movement By reducing uncertainties. A neural network sliding mode controller (NSMC) is applied with the objective to find the control law such that the joint motions of the space manipulator follow the given trajectory. A computed torque control (CTC) is an effective motion control strategy that is used in this paper for computing space manipulator arm torque to generate the required motion. NSMC will serve as a compensator to CTC such that the joint motions of the robotic manipulator follow the desired trajectories. Based on the Lyapunov stability theorem, the proposed intelligent controller NSMCTC guarantees the robustness and global asymptotic stability of the closed-loop control system. Finally, the controllers used in the paper are modelled and simulated using MATLAB Simulink. The results are presented to prove the effectiveness of the proposed controller approach.