Constrained optimal multi-phase lunar landing trajectory with minimum fuel consumption

The lunar landing stage is usually divided into two parts: deorbit burn and powered descent phases. The optimal lunar landing problem is likely to be transformed to the trajectory design problem on the powered descent phase by using continuous thrusters. The optimal lunar landing trajectories in general have variety in shape, and the lunar lander frequently increases its altitude at the initial time to obtain enough time to reduce the horizontal velocity. Due to the increment in the altitude, the lunar lander requires more fuel for lunar landing missions. In this work, a hybrid engine for the lunar landing mission is introduced, and an optimal lunar landing strategy for the hybrid engine is suggested. For this approach, it is assumed that the lunar lander retrofired the impulsive thruster to reduce the horizontal velocity rapidly at the initiated time on the powered descent phase. Then, the lunar lander reduced the total velocity and altitude for the lunar landing by using the continuous thruster. In contradistinction to other formal optimal lunar landing problems, the initial horizontal velocity and mass are not fixed at the start time. The initial free optimal control theory is applied, and the optimal initial value and lunar landing trajectory are obtained by simulation studies.

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Design of lunar landing trajectory under constraints

Chinese Astronomy and Astrophysics ◽

10.1016/s0275-1062(01)00100-x ◽

2001 ◽

Vol 25 (4) ◽

pp. 464-477

Author(s):

Cheng Huang ◽

Xiao-gong Hu ◽

Xin Li

Keyword(s):

Lunar Landing ◽

Landing Trajectory

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Desensitized Optimal Trajectory for Multi-phase Lunar Landing 1 1Authors are thankful to DST-FIST for its financial support in acquiring DIDO software

IFAC-PapersOnLine ◽

10.1016/j.ifacol.2017.08.1391 ◽

2017 ◽

Vol 50 (1) ◽

pp. 6105-6109

Author(s):

S. Mathavaraj ◽

Radhakant Padhi

Keyword(s):

Financial Support ◽

Optimal Trajectory ◽

Lunar Landing ◽

Multi Phase

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Some Applications of the U. S. Steel MVEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100070461 ◽

1973 ◽

Vol 31 ◽

pp. 4-5

Author(s):

J. S. Lally ◽

L. E. Thomas ◽

R. M. Fisher

Keyword(s):

Electron Diffraction ◽

Debye Temperature ◽

Metals And Alloys ◽

Critical Voltage ◽

Dynamical Diffraction ◽

Phase Structures ◽

Structure Factors ◽

Local Bonding ◽

Diffraction Phenomenon ◽

Multi Phase

A variety of materials containing many different microstructures have been examined with the USS MVEM. Three topics have been selected to illustrate some of the more recent studies of diffraction phenomena and defect, grain and multi-phase structures of metals and minerals.(1) Critical Voltage Effects in Metals and Alloys - This many-beam dynamical diffraction phenomenon, in which some Bragg resonances vanish at certain accelerating voltages, Vc, depends sensitively on the spacing of diffracting planes, Debye temperature θD and structure factors. Vc values can be measured to ± 0.5% in the HVEM ana used to obtain improved extinction distances and θD values appropriate to electron diffraction, as well as to probe local bonding effects and composition variations in alloys.

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Digital imaging and quantitative image analysis of polymer blends

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100163319 ◽

1996 ◽

Vol 54 ◽

pp. 170-171

Author(s):

Xiao Zhang

Keyword(s):

Digital Imaging ◽

Imaging Techniques ◽

Imaging Systems ◽

Polymer Science ◽

Key Factors ◽

Multiple Imaging ◽

Quantitative Image ◽

Digital Imaging Systems ◽

Multi Phase ◽

Network Technologies

Polymer microscopy involves multiple imaging techniques. Speed, simplicity, and productivity are key factors in running an industrial polymer microscopy lab. In polymer science, the morphology of a multi-phase blend is often the link between process and properties. The extent to which the researcher can quantify the morphology determines the strength of the link. To aid the polymer microscopist in these tasks, digital imaging systems are becoming more prevalent. Advances in computers, digital imaging hardware and software, and network technologies have made it possible to implement digital imaging systems in industrial microscopy labs.

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