Performance evaluation of tether-net deployment with adjustable ejection angle

Abstract

Space debris capture using a tether-net has attracted considerable research attention. To prevent the collapse of the tether-net before debris capture (caused by tension after deployment), various approaches have been proposed, such as the addition of an adhesive material to the tether-net perimeter, use of a net mouth-closing mechanism, or use of a thruster module attached to a weight that controls the weight trajectory after the ejection. However, these mechanisms complicate the net design. To prevent the tether-net collapse prior to debris capture and to ensure its full deployment just before contact with the debris, the tether-net ejection angle must be adjusted in accordance with the distance from the ejector to the debris. In this study, a tether-net ejection mechanism with an adjustable ejection angle is proposed. Moreover, to precisely predict the deployment and bouncing/shrinking behavior of the tether-net, the damping ratio of the net string was determined. Comparison between simulations based on the determined damping ratio and experiments demonstrated good agreement in the maximum deployment area, time to attain the maximum deployment, and the rebound and retraction speeds of the tether-net after complete deployment for large ejection angles. The study findings can contribute to the optimal ejection-angle selection for successful debris capture and prediction of the tether-net behavior after full deployment.