Right now, satellites are single use only. They are discarded because of running low on fuel, a failure or outdated equipment. True sustainable spaceflight means creating a circular economy in space, with developing in-orbit servicing as the way forward.
That is why the long-term vision for sustainability of ESA's Space Safety programme includes building a circular economy in space. A tough technological challenge? Yes. Yet it is no longer the realm of sci-fi, we can get there one technological step at a time.