Investigation of On-Orbit Electodynamic Tether Deployment by Ground Experiment and Numerical Simulation using a Detailed Friction Model

Paper number

IAC-12,C1,8,10,x14967

Author

Mr. Mitsuhisa Baba, Waseda University, Japan

Coauthor

Ms. Satomi Kawamoto, Japan

Coauthor

Mr. Kentaro IKI, Waseda University, Japan

Coauthor

Prof.Dr. Yoshiki Morino, Waseda University, Japan

Year

2012

Abstract

The pollution of the space environment by space debris is one of the most serious 
problems in space. As an effective means of removing space debris growth, the 
Aerospace Research and Development Directorate of the Japan Aerospace Exploration 
Agency (JAXA) has been investigating an active space debris removal system that 
employs highly efficient Electrodynamic tether (EDT) system for de-orbit into a 
disposal orbit. An electromotive force is set up within conductive net-type bare tethers 
deployed from space debris as it moves through the geomagnetic field around the earth. 
If a pair of plasma contactors at either end of the tether emits and collects electrons, the 
circuit is closed via the ambient plasma and an electric current flow through the tether. 
The interaction between the current and the geomagnetic field then generates a Lorentz 
force on the tether which acts opposite to the direction of flight. In some previous tether 
flight experiments, tether deployment stopped halfway because the deployment friction 
was greater than expected. The force was modeled by means of an experiment that was 
done by end-mass installing the tether inside on an air table. But the model is a liner 
function of deployment velocity. It needs to estimate the force in detail by other 
experiments. Thus this study investigates the deployment friction and deployment 
dynamics in numerical simulations. First, we estimated deployment friction by means of 
a deployment experiment using a high sensitivity force sensor. The sensor was used for 
hanging reel case installing the tether and measured the severity and behavior of the 
force directly. By this experiment, we found the friction tends to vibrate according to 
tether deployment and tangle among tethers often stops tether from deploying. Next, 
tether deployment using the EDT mechanism proposed for the flight demonstration was analyzed by numerical simulation. The tether was modeled as a lumped mass by 
dividing it into point masses connected by segments consists of a spring and viscous 
damper to consider tether flexibility. This simulation showed the vibration tendency of 
the deployment friction according to tether deployment has a low influence on the 
deployment and if the end-mass doesn’t has initial velocity enough, tether deployment 
will be stopped by the tangle.

Abstract document

IAC-12,C1,8,10,x14967.brief.pdf

Manuscript document

IAC-12,C1,8,10,x14967.pdf (🔒 authorized access only).

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