scholarly journals A Unified Framework for Aerocapture Systems Analysis

2019 ◽  
Author(s):  
Athul Pradeepkumar Girija
Keyword(s):  
Systems Analysis ◽  
Mission Design ◽  
Vehicle Design ◽  
Trajectory Design ◽  
Unified Framework ◽  
Trade Offs ◽  
Subsystem Level ◽  
Interplanetary Trajectory ◽  
Level Analysis ◽  
Systems Studies

A unified framework for aerocapture systems analysis studies is presented, taking into account the interconnected nature of interplanetary trajectory design and vehicle design. One of the limitations of previous aerocapture systems studies is their focus on a single interplanetary trajectory for detailed subsystem level analysis. The proposed framework and aerocapture feasibility charts enable a mission designer to perform rapid trajectory and vehicle design trade-offs, and is illustrated with its application to a Neptune mission. The approach can be applied to other atmosphere-bearing Solar System destinations. The framework can be be implemented in an aerocapture software suite to enable rapid mission design studies.

scholarly journals Asteroid Rendezvous Mission Design Using Multiobjective Particle Swarm Optimization

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Ya-zhong Luo ◽  
Li-ni Zhou
Keyword(s):  
Particle Swarm Optimization ◽  
Particle Swarm ◽  
Optimization Techniques ◽  
Mission Design ◽  
Trajectory Design ◽  
Time Transfer ◽  
Pareto Solution ◽  
Swarm Optimization ◽  
Multiobjective Particle Swarm Optimization ◽  
Asteroid Mission

A new preliminary trajectory design method for asteroid rendezvous mission using multiobjective optimization techniques is proposed. This method can overcome the disadvantages of the widely employed Pork-Chop method. The multiobjective integrated launch window and multi-impulse transfer trajectory design model is formulated, which employes minimum-fuel cost and minimum-time transfer as two objective functions. The multiobjective particle swarm optimization (MOPSO) is employed to locate the Pareto solution. The optimization results of two different asteroid mission designs show that the proposed approach can effectively and efficiently demonstrate the relations among the mission characteristic parameters such as launch time, transfer time, propellant cost, and number of maneuvers, which will provide very useful reference for practical asteroid mission design. Compared with the PCP method, the proposed approach is demonstrated to be able to provide much more easily used results, obtain better propellant-optimal solutions, and have much better efficiency. The MOPSO shows a very competitive performance with respect to the NSGA-II and the SPEA-II; besides a proposed boundary constraint optimization strategy is testified to be able to improve its performance.

Systems Studies of DDT Transport: A systems analysis provides new insights for predicting long-term impacts of DDT in ecosystems

Science ◽  
1970 ◽  
Vol 170 (3957) ◽  
pp. 503-508 ◽  
Author(s):  
H. L. Harrison ◽  
J. W. Mitchell ◽  
O. L. Loucks ◽  
D. F. Parkhurst ◽  
C. R. Tracy ◽  
...  
Keyword(s):  
Systems Analysis ◽  
Systems Studies

scholarly journals Solution for Nonlinear Three-Dimensional Intercept Problem with Minimum Energy

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Henzeh Leeghim ◽  
Donghoon Kim ◽  
James Turner
Keyword(s):  
Optimization Problem ◽  
Minimum Energy ◽  
Three Dimensional ◽  
Problem Formulation ◽  
Initial Position ◽  
Iteration Algorithm ◽  
Trajectory Design ◽  
Interplanetary Trajectory ◽  
Classical Orbit ◽  
Hohmann Transfer

Classical orbit intercept applications are commonly formulated and solved as Lambert-type problems, where the time-of-flight (TOF) is prescribed. For general three-dimensional intercept problems, selecting a meaningful TOF is often a difficult and an iterative process. This work overcomes this limitation of classical Lambert’s problem by reformulating the intercept problem in terms of a minimum-energy application, which then generates both the desired initial interceptor velocity and the TOF for the minimum-energy transfer. The optimization problem is formulated by using the classical Lagrangianfandgcoefficients, which map initial position and velocity vectors to future times, and a universal time variablex. A Newton-Raphson iteration algorithm is introduced for iteratively solving the problem. A generalized problem formulation is introduced for minimizing the TOF as part of the optimization problem. Several examples are presented, and the results are compared with the Hohmann transfer solution approaches. The resulting minimum-energy intercept solution algorithm is expected to be broadly useful as a starting iterative for applications spanning: targeting, rendezvous, interplanetary trajectory design, and so on.

An Evaluation Method for Environmental-Systems Planning: An Alternative Utility Approach

1979 ◽  
Vol 11 (2) ◽  
pp. 149-168 ◽  
Author(s):  
F Seo ◽  
M Sakawa
Keyword(s):  
Systems Analysis ◽  
Large Scale ◽  
Evaluation Method ◽  
Social Systems ◽  
Mathematical Formulation ◽  
Effective Control ◽  
Lagrangian Multiplier ◽  
Environmental Systems ◽  
Trade Offs ◽  
Utility Approach

This paper is concerned with constructing a comprehensive standard for evaluating regional environmental systems. Because such systems are composed of complex natural, economic, and social systems, conventional engineering and economic methods are virtually ineffective for this purpose. Systems-analysis methods appear suited to providing proper evaluation as well as effective control of environmental systems. But, in applying systems analysis to environmental evaluation, we are faced with the problem of measuring numerically the level of satisfaction of the region's residents. Environmental systems are very large in scale, and the components (attributes) which contribute to quality of life are not only many and various but often conflict with each other. In addition they are not commensurable. Therefore new methodologies for evaluating environmental systems must be developed. In such complex large-scale systems analyses, it is necessary, whatever the method used, to structure objectives by means of decomposition and ordering, and the construction of a preference hierarchy is an effective way to perform this structuring. The utility approach to decision analysis is employed to choose the best solutions under this interactive procedure. However, environmental systems also permit, to some extent, the possibility of mathematical formulation in a more rigorous form. Shadow prices (dual optimal variables) are good criteria for evaluating a constrained system's performance. We provide some devices (1) to utilize dual variables obtained in mathematical programming, (2) to nest them into multiattribute utility functions in a hierarchical system, (3) to articulate value trade-offs, and (4) to clarify priorities among objectives. These four procedures constitute the nested Lagrangian-multiplier method.

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