https://newatlas.com/omega-reintroduces-moon-watch-movement/58014/

A classic of the mechanical watch world has received a new lease on life after Omega announced it would restart production of its Calibre 321 after 51 years. Famous for powering the watches that US astronauts wore during the Gemini and Apollo missions, the new 321 chronograph movement was recreated by extensive research and reverse engineering.