Second stage reusability was certainly proposed by SpaceX: https://spaceflightnow.com/2017/04/11/musk-wants-to-make-falcon-9-rocket-fully-reusable/ https://spa

Second stage reusability was certainly proposed by SpaceX: https://spaceflightnow.com/2017/04/11/musk-wants-to-make-falcon-9-rocket-fully-reusable/ https://spaceflightnow.com/2017/04/11/musk-wants-to-make-fal... https://arstechnica.com/science/2017/04/this-six-year-old-video-from-spacex-is-both-prescient-and-pure-troll/ https://arstechnica.com/science/2017/04/this-six-year-old-vi... https://youtu.be/4rC2Z5El-8E https://youtu.be/4rC2Z5El-8E [Everyday Astronaut - Can SpaceX Reuse a second stage?]