Measurement of mechanical characteristics of tape tethers for space applications

According to current international guidelines introduced to mitigate the space debris problem, spacecraft in Low Earth Orbit (LEO) shall implement post-mission disposal strategies in order to be deorbited within 25 years from the end of their operative life. Among the proposed deorbiting technologies, electrodynamic tethers are an effective and promising option. In this context, the European Union is currently funding the H2020 Future Emerging Technologies (FET) Open project E.T.PACK – Electrodynamic Tether Technology for Passive Consumable-less Deorbit Kit. The measurement of elastic and damping characteristics of tape tethers is very important because those properties affect the dynamic stability of tethers during both deployment and deorbiting phases. This paper shows the experimental setup and the analysis methods that we have designed and employed to estimate the elastic modulus and the damping ratio of a tape tether made of PEEK for electrodynamic tethers applications. Three methods of experimental data analysis are described and compared, along with the related uncertainty analysis. In addition, relevant laboratory results are shown.