https://news.ycombinator.com/item?id=15678401 ("France’s Prometheus reusable engine becomes ESA project, gets funding boost" (2017))
https://news.ycombinator.com/item?id=36448791 ("Full ignition for ESA’s reusable rocket engine" (2023))
https://www.esa.int/Enabling_Support/Space_Transportation/Th... ("Themis is an ESA rocket prototype – a flagship European demonstrator for low-cost rocket recovery and reuse technologies")
edit: Before that, they also had an unusual concept from 2010, which envisioned first-stage liquid engines with wings that would detach from the booster and fly themselves back. Nothing came from that.
https://www.bbc.com/news/science-environment-33006056 ("Airbus unveils 'Adeline' re-usable rocket concept")
https://news.ycombinator.com/item?id=15678401 ("France’s Prometheus reusable engine becomes ESA project, gets funding boost" (2017))
https://news.ycombinator.com/item?id=36448791 ("Full ignition for ESA’s reusable rocket engine" (2023))
https://www.esa.int/Enabling_Support/Space_Transportation/Th... ("Themis is an ESA rocket prototype – a flagship European demonstrator for low-cost rocket recovery and reuse technologies")
edit: Before that, they also had an unusual concept from 2010, which envisioned first-stage liquid engines with wings that would detach from the booster and fly themselves back. Nothing came from that.
https://www.bbc.com/news/science-environment-33006056 ("Airbus unveils 'Adeline' re-usable rocket concept")