If Vanguard was build in KSP
Vanguard was the one of the direct competitors to Sputnik. It launched actually before Sputnik, but the rocket exploded on the pad. The Vanguard satellite was later placed into orbit with another rocket and remains there to this day.
Today's guessing Question:
?
Hint: .
Answer in the comment section!
The Rocket was replicated in Kerbal Space Program.
No mods were used, but DLC's might be required.