Space subsystems design: (navigation, control, structure and…)
Mohammad Javad Poustini; Seyed Hossein Sadati; Yosof Abbasi; Seyyed Majid Hosseini
Volume 15, Issue 1 , March 2022, , Pages 51-62
Abstract
Trajectory optimization is a familiar method for most of re-entry and Re-usable vehicles. This is because of the ability to include almost all of the problem constraints without facing restrictions such as time & Calculation issues. Adding or removing constraints in trajectory optimization problem ...
Read More
Trajectory optimization is a familiar method for most of re-entry and Re-usable vehicles. This is because of the ability to include almost all of the problem constraints without facing restrictions such as time & Calculation issues. Adding or removing constraints in trajectory optimization problem has significant effects on overall optimization performance which even can upgrade the method to an on-line process. Most of optimization Algorithms such as nonlinear-programming need an initial guess and are also sensitive to it. Hence in this research management of initial guess is done to remove some constraints from optimization problem and transfer them to initial phase. Accordingly an effort is conducted through using a classic guidance method to satisfy constraints of distance error and angle of impact command. The output of guidance initial guess is then fed to the optimization problem. 6Dof Simulation results show the increase of optimization performance via reduced number of iterations and Optimization time and increased solution accuracy.
Space systems design (spacecraft, satellites, space stations and their equipment)
Ghasem Heydari; Maryam Kiani; S. Hossein Pourtakdost; Mohammad Sayanjali
Volume 13, Issue 3 , September 2020, , Pages 25-38
Abstract
Halo orbits are of importance for observation and study of the space due to their specific characteristics including the orbital position and the periodic motion. In this regards, present paper has focused on optimal trajectory planning to transfer to halo orbits. To this aim, homotopy approach has been ...
Read More
Halo orbits are of importance for observation and study of the space due to their specific characteristics including the orbital position and the periodic motion. In this regards, present paper has focused on optimal trajectory planning to transfer to halo orbits. To this aim, homotopy approach has been adopted for optimal trajectory design. This approach has improved the convergence rate and insensitivity of the problem to initial guess. The designed trajectory transfers a spacecraft orbiting the Earth to a Halo orbit around Lagrangian point L1 of the Earth-moon restricted three-body system. The propulsion system has been assumed to be low thrust with constant specific impulse. Homotopy approach has a broad domain of applicability and methods in which continuation method has been employed here among them. The optimal designed trajectory minimizes the fuel consumption via transforming solution of the minimum energy problem utilizing the homotopy approach. This approach simplifies solution of the complex problem of minimum fuel indeed.
