Space debris is positioned as a fatal problem for current and future space missions.
Many e ective space debris removal methods have been proposed in the
past decade, and several techniques have been either tested on the ground or
in parabolic
ight experiments. Nevertheless, no uncooperative debris has been
removed from any orbit until this moment. Therefore, to expand this research
eld and progress the development of space debris removal technologies, this
paper reviews and compares the existing technologies with past, present, and
future methods and missions. Moreover, since one of the critical problems when
designing space debris removal solutions is how to transfer the energy between
the chaser/de-orbiting kit and target during the rst interaction, this paper proposes
a novel classi cation approach, named ET-Class (Energy Transfer Class).
This classi cation approach provides an energy-based perspective to the space
debris phenomenon by classifying how existing methods dissipate or store energy
during rst contact
