# Abolfazl ShiraziZerua Tech

Abolfazl Shirazi

Ph.D. | Computer Science | Machine Learning | Astrodynamics

Open for collaboration

## About

20

Publications

26,865

Reads

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294

Citations

Introduction

Postdoctoral Researcher at BCAM. Research interests include
Spacecraft Trajectory Optimization, Evolutionary Computations, Space Dynamics and Control, Numerical Simulation, Orbital Mechanics, Machine Learning and Meta-heuristics

Additional affiliations

February 2020 - July 2020

October 2016 - March 2021

January 2010 - December 2015

Education

October 2017 - March 2021

September 2010 - September 2012

September 2006 - September 2010

## Publications

Publications (20)

This article is a survey paper on solving spacecraft trajectory optimization problems. The solving process is decomposed into four key steps of mathematical modeling of the problem, defining the objective functions, development of an approach and obtaining the solution of the problem. Several subcategories for each step have been identified and des...

Handling non-linear constraints in continuous optimization is challenging, and finding a feasible solution is usually a difficult task. In the past few decades, various techniques have been developed to deal with linear and non-linear constraints. However, reaching feasible solutions has been a challenging task for most of these methods. In this pa...

A direct adaptive scheme is presented as an alternative approach for minimum-fuel low-thrust trajectory design in non-coplanar orbit transfers using fitness landscape analysis (FLA). The spacecraft dynamics is modeled with respect to modified equinoctial elements by considering [Formula: see text] orbital perturbations. Taking into account the timi...

One particular kind of evolutionary algorithms known as Estimation of Distribution Algorithms (EDAs) has gained the attention of the aerospace industry for its ability to solve nonlinear and complicated problems, particularly in the optimization of space trajectories during on-orbit operations of satellites. This article describes an effective meth...

Enhancements in evolutionary optimization techniques are rapidly growing in many aspects of engineering, specifically in astrodynamics and space trajectory optimization and design. In this chapter, the problem of optimal design of space trajectories is tackled via an enhanced optimization algorithm within the framework of Estimation of Distribution...

Space missions with low-thrust propulsion systems are of appreciable interest to space agencies because of their practicality due to higher specific impulses. This research proposes a technique to the solution of minimum-fuel non-coplanar orbit transfer problem. A direct adaptive method via Fitness Landscape Analysis (FLA) is coupled with a constra...

In this paper, a direct approach is developed for discovering optimal transfer trajectories of close-range rendezvous of satellites considering disturbances in elliptical orbits. The control vector representing the inputs is parameterized via different interpolation methods, and an Estimation of Distribution Algorithm (EDA) that implements mixtures...

In this article, an interactive tool for simulation of satellites dynamics and autonomous spacecraft guidance is presented. Different geopotential models for orbit propagation of Earth-orbiting satellites are provided, which consider earth's gravitational field with various accuracies. The presented software is a 3-D visualization platform for spac...

Meta-heuristics has a long tradition in computer science. During the past few years, different types of meta-heuristics, specially evolutionary algorithms got noticeable attention in dealing with real-world optimization problems. Recent advances in this field along with rapid development of high processing computers, make it possible to tackle vari...

In this paper, an approach is presented for finding the optimal long-range space rendezvous in terms of fuel and time, considering limited impulse. In this approach , the Lambert problem is expanded towards a discretized multi-impulse transfer. Taking advantage of an analytical form of multi-impulse transfer, a feasible solution that satisfies the...

In this paper, a direct approach is presented to tackle the multi-impulse rendezvous problem considering the impulse limit. Particularly, the standard Lambert problem is extended toward several consequential orbit transfers for the rendezvous problem. A number of different evolutionary algorithms are taken into consideration. It is shown that the p...

In space environment, perturbations make the spacecraft lose its predefined orbit in space. One of these undesirable changes is the in-plane rotation of space orbit, denominated as orbital precession. To overcome this problem, one option is to correct the orbit direction by employing low-thrust trajectories. However, in addition to the orbital pert...

Optimization of orbital maneuvers is one of the main issues in conceptual and preliminary design of spacecraft in different space missions. The main issue in optimization of high-thrust orbit transfers is that the common optimization algorithms such as Genetic Algorithm and Simulated Annealing are not effectual in finding optimal transfer when they...

This article introduces a new method to optimize finite-burn orbital manoeuvres based on a modified evolutionary algorithm. Optimization is carried out based on conversion of the orbital manoeuvre into a parameter optimization problem by assigning inverse tangential functions to the changes in direction angles of the thrust vector. The problem is a...

Spacecraft performance in an orbital maneuver relies on guidance and control systems which manage the thrust direction within orbit transfer. In this article, the guidance and control approach for spacecraft having a 3D orbit transfer mission is proposed. To derive the optimal variation of steering angles with initial and terminal constraints on th...

The attitude determination and control subsystem is tasked with identifying the location and the orientation of the satellite at all times during the mission. Momentum exchange actuators such as reaction wheels are mounted on the satellites to transfer some of their torque, turning them through its centre of mass along each of three axes. In this p...

A combination of low-cost micro-electoro-mechanical sensors (MEMSs) and nonlinear attitude estimation algorithm techniques can provide an inexpensive and accurate system for navigation and attitude determination. The features of MEMSs are their light weight and small size; hence, the MEMSs have found significant attention in low-cost navigation and...

The pyramidal reaction wheel arrangement is one of the configurations that can be used in attitude control simulators for evaluation of attitude control performance in satellites. In this arrangement, the wheels are oriented in a pyramidal configuration with a tilt angle. In this paper, a study of pyramidal reaction wheel arrangement is carried out...

Accurate thermal modeling for each part in the satellite is needed for achieving temperature gradients. The result of such a modeling will be the temperature gradients of each element of the satellite as a function of time. The aim of this paper is to present a new software which has been developed recently by the author at Space Research Laborator...

## Questions

Question (1)

One major different between high thrust and low thrust trajectories are the thrust profiles for each of their propulsion systems.

For example in an orbit transfer using a solid rocket, the thrust profile is almost fixed and known with a predefined variation (neutral, progressive or regressive) and it is impossible to change the magnitude of the thrust during the burn time.

However, according to the literatures, it is possible to have variable thrust magnitude during the transfer in low thrust propulsion system.

I have read so many papers about low thrust trajectory design and optimization in different journals. Most of them contain profiles of thrust vector and its magnitude. The authors claim that they have found an “optimal” thrust variation that makes a trajectory which transfers the spacecraft from one orbit to another. We can find so many papers in which the transfer trajectory is modeled using

**Fourier series**,**Chebyshev polynomials**or different kind of mathematical functions.My question is:

**“Are these thrust variations truly achievable in a real space mission?”**

**“Are low thrust propulsion systems nowadays capable of providing such thrust profiles?”**

If yes then:

**“How much thrust variation (Newton per second) is allowed in a low thrust trajectory?”**

I already know that the limit of thrust magnitude can be up to 1 Newton typically in low thrust transfers. Please note that my question is about “the variation (the rate of increment or reduction)”, not the limit of the thrust profile.

I would appreciate if you answer with references.

Thanks in advance