Trajectory Optimization for an Apollo-type Vehicle Under Entry Conditions Encountered During Lunar Return PDF Download

Author: John W. Young
Publisher:
ISBN:
Category : Space trajectories
Languages : en
Pages : 50

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Author:
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ISBN:
Category :
Languages : en
Pages : 39

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Category : Government publications
Languages : en
Pages :

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Author:
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ISBN:
Category :
Languages : en
Pages : 88

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The Bulletin of the Atomic Scientists is the premier public resource on scientific and technological developments that impact global security. Founded by Manhattan Project Scientists, the Bulletin's iconic "Doomsday Clock" stimulates solutions for a safer world.

Author: Ashley Trent
Publisher:
ISBN:
Category : Aerodynamics, Hypersonic
Languages : en
Pages : 18

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Recently, several authors have studied the problem of trajectory redesign for hypersonic aircraft. The usual procedure for solving such problems is to set it up as a constrained optimal control problem. Lu and Schierman used direct methods to numerically solve the optimal control problems. Alternatively, one could use Pontryagin's Minimum Principle to obtain first-order necessary conditions for the optimal control problem and obtain a two-point boundary-value problem (TPBVP). Originally created to solve two-point boundary value problems (TPBVPs), the Modified Simple Shooting Method (MSSM) has been shown to be superior, both in speed and accuracy, to known methods for solving TPBVPs. Since optimal control problems can be formulated with differential equations and boundary conditions, it seems feasible to propose that the MSSM could be used to solve problems in optimal control. Here, the original MSSM algorithm was altered and used in conjunction with Pontryagin's Minimum Principle in an attempt to solve an optimal control problem in trajectory generation. In this paper, the authors consider the problem of trajectory redesign of the unpowered reentry phase for a hypersonic air vehicle. They consider outer loop equations governing the motion of the center of mass and consider the angle of attack to be the input variable. The lift and drag forces for the aircraft considered were obtained from a polynomial neural network approximation of experimental data. Effector deflections were chosen so that the aircraft Underwent trimmed flight. (6 figures, 7 refs.).

Author: Runqi Chai
Publisher: Springer Nature
ISBN: 9819943116
Category : Technology & Engineering
Languages : en
Pages : 272

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This book focuses on the design and application of advanced trajectory optimization and guidance and control (G&C) techniques for aerospace vehicles. Part I of the book focuses on the introduction of constrained aerospace vehicle trajectory optimization problems, with particular emphasis on the design of high-fidelity trajectory optimization methods, heuristic optimization-based strategies, and fast convexification-based algorithms. In Part II, various optimization theory/artificial intelligence (AI)-based methods are constructed and presented, including dynamic programming-based methods, model predictive control-based methods, and deep neural network-based algorithms. Key aspects of the application of these approaches, such as their main advantages and inherent challenges, are detailed and discussed. Some practical implementation considerations are then summarized, together with a number of future research topics. The comprehensive and systematic treatment of practical issues in aerospace trajectory optimization and guidance and control problems is one of the main features of the book, which is particularly suitable for readers interested in learning practical solutions in aerospace trajectory optimization and guidance and control. The book is useful to researchers, engineers, and graduate students in the fields of G&C systems, engineering optimization, applied optimal control theory, etc.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 88

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The Bulletin of the Atomic Scientists is the premier public resource on scientific and technological developments that impact global security. Founded by Manhattan Project Scientists, the Bulletin's iconic "Doomsday Clock" stimulates solutions for a safer world.

Author: Richard C. Rosenbaum
Publisher:
ISBN:
Category : Launch vehicles (Astronautics)
Languages : en
Pages : 60

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Author: Thomas J. Wong
Publisher:
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Category : Lift (Aerodynamics)
Languages : en
Pages : 24

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Entry corridors for manned vehicles returning from the moon are defined consistent with requirements for avoiding radiation exposure and for limiting values of peak deceleration. It was found that the use of lift increases the depth of the entry corridor and, hence, reduces guidance accuracy requirements. Mid-course guidance requirements appear to be critical only for the flight-path angle. Increasing the energy of the transfer orbit increases the required guidance for the flight-path angle. To correct a trajectory for an error in target perigee point, it was found that application of the corrective thrust essentially parallel to the local horizontal produces the maximum change in perigee altitude for a given increment of velocity. It was also found that the energy required to effect a given change in perigee altitude is not strongly dependent on the energy of the orbit, but it was found to vary inversely with range measured from the center of the earth. For this reason, it is important to detect and correct any errors in approach trajectory at the largest possible distance from the earth.

Author: Walton E. Williamson
Publisher:
ISBN:
Category : Mechanics, Applied
Languages : en
Pages : 264

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