Minimum-fuel Orbital Transfer Using Finite Thrust PDF Download

Author: Jerry L. Mrozek (CAPT, USAF.)
Publisher:
ISBN:
Category : Orbital transfer (Space flight)
Languages : en
Pages : 124

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Author: Begum Senses
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Category :
Languages : en
Pages :

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ABSTRACT: In this study, minimum fuel solutions to finite thrust noncoplanar aeroassisted orbital transfers of a small spacecraft between two low-Earth orbits are found using General Pseudospectral Optimal Control Software (GPOPS) which applies an hp-adaptive pseudospectral method. Optimal trajectories, and final mass ratios of the small spacecraft that are obtained subject to various inclination changes, heating rate constraints, and number of atmospheric passes are compared. It is observed that, fuel consumption is proportional to the inclination change, on the other hand, it is inversely proportional to the heating rate constraint. Furthermore, for the cases where the heating rate is not constrained, the number of atmospheric passes does not affect the fuel consumption. For the cases where the heating rate is constrained, increasing number of atmospheric passes, however, decreases fuel consumption.

Author: Harold Dean Childers
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ISBN:
Category :
Languages : en
Pages : 86

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The method of quasilinearization is applied to the solution of a system of lumped-parameter differential equations providing the necessary conditions for minimum-fuel finite-thrust transfers between coplanar orbits. A central gravitational field is assumed. The equations are derived from the basic equations describing the motion of a finite-thrust rocket. The method of optimization (a modification of quasilinearization for application to bang-bang control problems), and the computer program used to solve the problem are discussed. The method is found to be inapplicable to the problem as originally formulated, and reasons for the inapplicability are given. A new formulation is presented, and computer programming techniques relevant to its solution are discussed. A printout of the program is included. (Author).

Author: Eugene A. Smith
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ISBN:
Category :
Languages : en
Pages : 93

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Minimum fuel continuous low thrust orbit transfer is an optimal control problem which requires the application of iterative numerical methods to solve the resulting two point boundary value problem. A combination gradient- neighboring extremal algorithm gives accurate results when both the initial and terminal orbits are coplanar. These results are then used to extend the problem to include out-of-plane transfers between orbits of widely varying inclination. Control histories, in terms of thrust direction, are plotted as a function of time for both coplanar and non-coplanar transfers. Steering programs for coplanar transfers are characterized by a rapid thrust reversal which is dependent on eccentricity for the time of its occurrence. In the latter case, out-of-plane thrusting is primarily a function of the inclination change between orbits. On the basis of these results, the particular numerical approach used provides an effective method for generating optimal low thrust orbital transfer guidance.

Author: Daniel E. Gill
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ISBN:
Category :
Languages : en
Pages : 226

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A method is developed for computing improved initial-value estimates for minimum-fuel transfer trajectories between coplanar, elliptic orbits with a thrust-limited, variable-mass rocket moving in an inverse square-law gravitational field. The initial and final orbits are specified by their eccentricities, semilateral recta and arguments of pericenter and the entire transfer consists of two finite-thrust phases. Estimates for the parameters of the optimal transfer trajectory are provided by the two-impulse solution and the techniques presented in this study provide good estimates for the unknown initial values of unspecified control, state and adjoint variables which are required to successfully compute the minimum-fuel transfer trajectory between specified orbits. (Author).

Author: Richard N. Green
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ISBN:
Category : Error analysis (Mathematics)
Languages : en
Pages : 76

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A computer program was developed which performs an error analysis of a minimum-fuel, finite-thrust, transfer maneuver between two Keplerian orbits in the vicinity of Mars. The method of analysis is the Monte Carlo approach where each off-nominal initial orbit is targeted to the desired final orbit. The errors in the initial orbit are described by two covariance matrices of state deviations and tracking errors. The function of the program is to relate these errors to the resulting errors in the final orbit. The equations of motion for the transfer trajectory are those of a spacecraft maneuvering with constant thrust and mass-flow rate in the neighborhood of a single body. The thrust vector is allowed to rotate in a plane with a constant pitch rate. The transfer trajectory is characterized by six control parameters and the final orbit is defined, or partially defined, by the desired target parameters. The program is applicable to the deboost maneuver (hyperbola to ellipse), orbital trim maneuver (ellipse to ellipse), fly-by maneuver (hyperbola to hyperbola), escape maneuvers (ellipse to hyperbola), and deorbit maneuver.

Author: Eugene A. Smith (CAPT, USAF.)
Publisher:
ISBN:
Category : Orbital transfer (Space flight)
Languages : en
Pages : 160

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Author: 陳育民
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Category :
Languages : en
Pages : 194

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Author:
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Category :
Languages : en
Pages : 45

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The object of this study is to derive a set of equations which predict the results of orbital maneuvers of vehicles using constant low thrust. These equations are developed by simplifying the problem to circular orbits in a two-body dynamic system. The results are presented in three parts. The first part solves for the equation of the coplanar radius change problem. The second finds the equation for the minimum fuel inclination change problem. The third part of this study puts the equations from the first two parts together to solve a minimum fuel transfer problem involving both radius and inclination changes. The solution of the minimum fuel transfer problem is not to perform the total radius change and then perform the total inclination change. Instead, the solution is to perform both radius and inclination changes on a per orbit basis.

Author: Harold Dean Childers (CAPT, USAF.)
Publisher:
ISBN:
Category : Orbital transfer (Space flight)
Languages : en
Pages : 74

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