scholarly journals Electrodynamic Tethering: An Energy Source for Satellite

Author(s):  
T Guna Durga Prashanth

Abstract: There is a tremendous force interest for the satellites which the nations have been utilizing over a long time for correspondence, spying, tests, analysis, etc; and tracking down an elective energy hotspots for satellite has been a major undertaking that must be settled as quickly as time permits and electrodynamic tie situation can be the ideal decision for the force supplanting framework. The current existing strategies are somewhat more established, fusy and should be changed for expanded use office of a satellite. Electrodynamic ties are long, dainty conductive wires which are conveyed in space appended to the plasma bend generator of the satellite framework and can be utilized to create power by eliminating the motor energy from their orbital movement, or to deliver push while adding energy from an on board source. regardless , the frictional or push power is created electrodynamically , through the communication between the moving charges only the electrons of the ionospheric plasma and the attractive field of earth. Electrodynamic ties work by temperance of the power an attractive field applies on a current conveying wire which is only the lorentz power. Generally, it is a shrewd method of getting an electric flow to stream in a long directing wire that is circling Earth, so that world's attractive field will apply a power on and speed up the wire and thus any payload appended to it. By switching the bearing of current in it, a similar tie can be utilized to de-circle old satellite and once again circle them if necessary under the fundamental circumstances. Electrodynamic ties have solid potential for giving propellant less impetus to rocket in low-Earth orbit(LEO) for applications, for example, satellite deorbit circle boosting, and station keeping. The tie, in any case, is anything but an unbending pole held above or beneath the rocket. Keywords: Electrodynamic, Ionospheric plasma, LEO, Tethers, Deorbit, Reorbit, plasma arc generator.

2014 ◽  
Vol 32 (10) ◽  
pp. 1207-1216 ◽  
Author(s):  
P. Janhunen

Abstract. Plasma brake is a thin, negatively biased tether that has been proposed as an efficient concept for deorbiting satellites and debris objects from low Earth orbit. We simulate the interaction with the ionospheric plasma ram flow with the plasma-brake tether by a high-performance electrostatic particle in cell code to evaluate the thrust. The tether is assumed to be perpendicular to the flow. We perform runs for different tether voltage, magnetic-field orientation and plasma-ion mass. We show that a simple analytical thrust formula reproduces most of the simulation results well. The interaction with the tether and the plasma flow is laminar (i.e. smooth and not turbulent) when the magnetic field is perpendicular to the tether and the flow. If the magnetic field is parallel to the tether, the behaviour is unstable and thrust is reduced by a modest factor. The case in which the magnetic field is aligned with the flow can also be unstable, but does not result in notable thrust reduction. We also correct an error in an earlier reference. According to the simulations, the predicted thrust of the plasma brake is large enough to make the method promising for low-Earth-orbit (LEO) satellite deorbiting. As a numerical example, we estimate that a 5 km long plasma-brake tether weighing 0.055 kg could produce 0.43 mN breaking force, which is enough to reduce the orbital altitude of a 260 kg object mass by 100 km over 1 year.


2021 ◽  
Author(s):  
Sukhmander Singh ◽  
Sanjeev Kumar ◽  
Shravan Kumar Meena ◽  
Sujit Kumar Saini

Technically, there are two types of propulsion systems namely chemical and electric depending on the sources of the fuel. Electrostatic thrusters are used for launching small satellites in low earth orbit which are capable to provide thrust for long time intervals. These thrusters consume less fuel compared to chemical propulsion systems. Therefore for the cost reduction interests, space scientists are interested to develop thrusters based on electric propulsion technology. This chapter is intended to serve as a general overview of the technology of electric propulsion (EP) and its applications. Plasma based electric propulsion technology used for space missions with regard to the spacecraft station keeping, rephrasing and orbit topping applications. Typical thrusters have a lifespan of 10,000 h and produce thrust of 0.1–1 N. These devices have E→×B→ configurations which is used to confine electrons, increasing the electron residence time and allowing more ionization in the channel. Almost 2500 satellites have been launched into orbit till 2020. For example, the ESA SMART-1 mission (Small Mission for Advanced Research in Technology) used a Hall thruster to escape Earth orbit and reach the moon with a small satellite that weighed 367 kg. These satellites carrying small Hall thrusters for orbital corrections in space as thrust is needed to compensate for various ambient forces including atmospheric drag and radiation pressure. The chapter outlines the electric propulsion thruster systems and technologies and their shortcomings. Moreover, the current status of potential research to improve the electric propulsion systems for small satellite has been discussed.


2019 ◽  
pp. 10-23
Author(s):  
T. A. Akhadov ◽  
S. Yu. Guryakov ◽  
M. V. Ublinsky

For a long time, there was a need to apply magnetic resonance imaging (MRI) technique for lung visualization in clinical practice. The development of this method is stimulated by necessity of the emergence of an alternative to computed tomography, especially when radiation and injection of iodine-containing contrast agents are contraindicated or undesirable, for example, in pregnant women and children, people with intolerance to iodinated contrast. One of the reasons why lung MRI is still rarely used is lack of elaborated standardized protocols that would be adapted to clinical needs of medical society. This publication is a current literature review on the use of MRI in lung studies.


1983 ◽  
Author(s):  
I. KATZ ◽  
D. COOKE ◽  
D. PARKS ◽  
M. MANDELL ◽  
A. RUBIN

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