Review of KITE - Electrodynamic tether experiment on the H-II Transfer Vehicle

The growing amount of orbital debris is becoming a serious concern for space development activities. To remedy the situation, it is necessary to prevent new debris generation through highly probable post-mission disposal operations and remove existing large debris objects from crowded orbits. An electrodynamic tether (EDT) is a promising deorbit propulsion device for both purposes, as it is propellant-less in principle and thus simple and cost effective. An on-orbit EDT experiment called the Kounotori Integrated Tether Experiment (KITE) was conducted in early 2017 on the sixth H-II Transfer Vehicle (HTV-6) for demonstrating and raising the maturity of the core EDT technologies. In the KITE mission, EDT operation was planned using the combination of a bare tether (720 m long) and a field emission cathode (FEC). Although tether deployment was unsuccessful due to a mechanical malfunction of the holding & releasing mechanism of the end-mass, the FEC operated successfully throughout the mission period and demonstrated its capabilities in low Earth orbit (LEO). Another KITE device an electrical potential monitor called LP-POM - also operated successfully from HTV launch to re-entry, obtaining engineering and scientific results. In addition to these experimental results, the lessons learned during the development process are meaningful for future EDT research and development.