Shepard's suborbital, May 5, 1961.
Summer job: my boss and I stopped at the warehouse to pick up stuff and the warehouse guy had the event on his office TV. We watched the whole thing, along with a bunch of other people crowded into the office.
Then, back to work.
The importance was muffled by Gagarin's orbital flight three weeks before. So, not a yee-haw, but more of a "Yeah, we'll show 'em!"
How many remember the Vanguard failures? Finally, IIRC, von Braun convinced them to use the Redstone rocket, which was ready to go, and was the vehicle which put Shepard into suborbit. All, IIRC.
Corrections welcome.
https://youtu.be/zVeFkakURXM (0:53)