Carl Jung recorded his encounters with entities from “inner space”

 https://bigthink.com/high-culture/carl-jung-unconscious

https://en.wikipedia.org/wiki/The_Red_Book_(Jung)#Creation_and_physical_description

https://jungiancenter.org/jungs-prophetic-visions/

https://carljungdepthpsychologysite.blog/2020/04/28/carl-jung-on-visions-anthology

https://thenucleusmagazine.co.uk/2022/05/31/carl-jung-dreams-and-visions

Various people have had dreams or visions which have inspired them to write about possible future scenarios.

https://www.scientificamerican.com/article/h-g-wells-envisions-atomic-bomb-30-years-ahead-of-time/

https://www.warhistoryonline.com/war-articles/hg-wells-foresaw-a-future-with-nuclear-bombs.html

https://ahf.nuclearmuseum.org/ahf/key-documents/hg-wells-world-set-free 1914

https://www.bbc.com/news/magazine-33365776

HGW might not have specifically referred to it as The+Manhattan+Project, but the end result was a story about a new kind of extremely powerful weapon.