What if your character got a copy of this year's Jane's Books and went back to 1955 to let the superpowers know what's coming?
What challenges would your characters face? What an opportunity for fortune and fame would this lead to! To know what weapon systems the enemy will have 20 or 30 years from now.
Thoughts? Who would you contact? How would you convince them? How much would you ask? How would you explain yourself? What would you have to do to stay alive?