The Japan Aerospace Exploration Agency (JAXA) has been investigating Electrodynamic Tether (EDT) systems for de-orbiting existing debris. EDT is a high-efficiency propulsion system to generate Lorentz force by the interaction with the Earth's magnetic field. It is necessary to deploy a several kilometer tether in order to obtain sufficient thrust for large debris removal. In the deployment phase, excess of deployment velocity and in-plane libration by gravity gradient become issues, since the behavior of the tether becomes unstable or it is severed by the tension over in excess of the load limit. In some previous flight experiments, a barber pole brake was adapted as a simple brake to acquire effective braking force. However, the barber pole brake was applied for tether deployment with a non-conductive tether and a light satellite up to some tens of kilograms. The purpose of this study is to build a simple barber pole brake using a net-type bare conductive tether and a relatively heavy satellite of about several hundred kilograms. First, a braking force model is built based on on-ground tests with a high-sensitive sensor. Next, numerical simulations about tether deployment dynamics on orbit are performed in order to investigate its applicable limitation. In the numerical simulations using the brake model from the on-ground tests, a 10-km-long tether is deployed, and the changes in the form of the tether and the tether oscillations are also calculated. The simulation confirmed that the barber pole brake can decrease the in-plane libration angle to less than ±10 deg, and the maximum tension up to the half value of the tether load limit 160N.
内容記述
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内容記述（英）
Physical characteristics: Original contains color illustrations
Evaluation of a barber pole brake in deployment of conductive tether for debris removal
AA1630052045.pdf
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