Universidad Carlos III de Madrid (UC3M) coordinates a European research project, called E.T.PACK, whose objective is the development of a new system for deorbiting space satellites without using on board power and fuel. For this purpose, a new experimental technology will be employed: a low work-function tether.
Source:
https://phys.org/news/2019-06-deorbit-kit-satellites-based-work-function.html