And for trying to prove the technological and scientific superiority of the United States' system over the Communist system during the Cold War, which was at least 50% of the effort.
Not sure I'd call them heroes, since I define term as "someone who saves or helps other people" and that is what astronauts usually don't do. But they certainly were brave men.
Astronauts are absolutely heroes, they are pioneers in space just like Magellan and Cook were on Earth.
While I agree the US likes to forget and gloss over what was achieved by their enemy on Oct. 4, 1957, the fact is that police and firemen don't own the word "hero". All one of them has to do is stub their toe in the pursuit of a criminal or during a fire and the media is falling over themselves calling them heroes. I know they are saving & helping people and that's great but its also their JOB, no one else gets to fly across country on the city's dime when someone with the same occupation as them dies.