Exponentially Convergent Velocity Observer for an Electrodynamic Tether in an Elliptical Orbit

2016 ◽  
Vol 39 (5) ◽  
pp. 1113-1118 ◽  
Author(s):  
Hao Wen ◽  
Zheng H. Zhu ◽  
Dongping Jin ◽  
Haiyan Hu
Keyword(s):  
Elliptical Orbit ◽  
Electrodynamic Tether ◽  
Velocity Observer

scholarly journals Orbit Decomposition Method for Rotordynamic Coefficients Identification of Annular Seals

2021 ◽  
Vol 11 (9) ◽  
pp. 4237
Author(s):  
Mingjie Zhang ◽  
Jiangang Yang ◽  
Wanfu Zhang ◽  
Qianlei Gu
Keyword(s):  
Circular Orbit ◽  
Present Method ◽  
Decomposition Method ◽  
Parameter Analysis ◽  
Elliptical Orbit ◽  
Computational Time ◽  
Solution Technique ◽  
Rotordynamic Coefficients ◽  
Cfd Method ◽  
Annular Seals

The elliptical orbit whirl model is widely used to identify the frequency-dependent rotordynamic coefficients of annular seals. The existing solution technique of an elliptical orbit whirl model is the transient computational fluid dynamics (CFD) method. Its computational time is very long. For rapid computation, this paper proposes the orbit decomposition method. The elliptical whirl orbit is decomposed into the forward and backward circular whirl orbits. Under small perturbation circumstances, the fluid-induced forces of the elliptical orbit model can be obtained by the linear superposition of the fluid-induced forces arising from the two decomposed circular orbit models. Due to that the fluid-induced forces of circular orbit, the model can be calculated with the steady CFD method, and the transient computations can be replaced with steady ones when calculating the elliptical orbit whirl model. The computational time is significantly reduced. To validate the present method, its rotordynamic results are compared with those of the transient CFD method and experimental data. Comparisons show that the present method can accurately calculate the rotordynamic coefficients. Elliptical orbit parameter analysis reveals that the present method is valid when the whirl amplitude is less than 20% of seal clearance. The effect of ellipticity on rotordynamic coefficients can be ignored.

scholarly journals Deployment requirements for deorbiting electrodynamic tether technology

2021 ◽  
Author(s):  
Giulia Sarego ◽  
Lorenzo Olivieri ◽  
Andrea Valmorbida ◽  
Alice Brunello ◽  
Enrico C. Lorenzini ◽  
...  
Keyword(s):  
Lorentz Force ◽  
Electrodynamic Tether ◽  
Operational Life ◽  
Electrodynamic Tethers

AbstractIn the last decades, green deorbiting technologies have begun to be investigated and have raised a great interest in the space community. Among the others, electrodynamic tethers appear to be a promising option. By interacting with the surrounding ionosphere, electrodynamic tethers generate a drag Lorentz force to decrease the orbit altitude of the satellite, causing its re-entry in the atmosphere without using propellant. In this work, the requirements that drive the design of the deployment mechanism proposed for the H2020 Project E.T.PACK—Electrodynamic Tether Technology for Passive Consumable-less Deorbit Kit—are presented and discussed. Additionally, this work presents the synthesis of the reference profiles used by the motor of the deployer to make the tethered system reach the desired final conditions. The result is a strategy for deploying electrodynamic tape-shaped tethers used for deorbiting satellites at the end of their operational life.

On the Deployment of a Tether from an Elliptical Orbit

1998 ◽  
Vol 46 (2) ◽  
pp. 119-133 ◽  
Author(s):  
M. Ruiz ◽  
J. Peláez
Keyword(s):  
Elliptical Orbit

scholarly journals The TSS-1R electrodynamic tether experiment: Scientific and technological results

1999 ◽  
Vol 24 (8) ◽  
pp. 1037-1045 ◽  
Author(s):  
N.H. Stone ◽  
W.J. Raitt ◽  
K.H. Wright
Keyword(s):  
Electrodynamic Tether
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