Wernher von Braun himself also wrote probably the first serious treatise on human missions to mars as well as a science fiction novel on the topic in 1948. Apparently the original German novel remains unpublished, but there is an English translation available. It’s set in 1980.
https://en.wikipedia.org/wiki/The_Mars_Project
https://en.wikipedia.org/wiki/Project_Mars:_A_Technical_Tale
Check out the second link’s section about “the Elon”.