Alan Shepard became the first American to travel in space on May 5, 1961.
Former University of Missouri professor and retired NASA Astronaut Linda Godwin said Shepard's mission made a lasting impact on space explorations that followed -- even hers.
"For one thing, it stood out," Godwin said. "We've had to start with that step, to move along and get to be where we are."
Godwin was only 8 years old when Shepard took flight, and she remembers being fascinated.
"When I was a kid at that age, I didn't have any clue that I could do that," she said. "They didn't have any women, and it seemed very far away from the environment where I was growing up."