John Glenn was a NASA astronaut in the 20th century. He was the third American astronaut to travel in space and the first American to complete an orbit of the Earth in 1962.
Centuries later, in 2376, Chakotay remarked that Glenn, along with fellow astronauts John Kelly, Rose Kumagawa, and Neil Armstrong were Earth's true space pioneers. (VOY: "One Small Step")
Scott Carpenter's quote "Godspeed John Glenn" was used in the Star Trek teaser trailer.