Mercury Seven
John Glenn
First American to orbit the Earth; returned to space at 77 aboard the shuttle.
John Glenn, a Marine Corps fighter pilot with combat tours in World War II and Korea, became a national hero as the first American to orbit the Earth aboard Friendship 7 in 1962. His calm handling of a feared heat-shield problem cemented the astronaut-as-icon image.
Glenn left NASA for a quarter-century career as a U.S. Senator from Ohio, then made history again in 1998 by flying aboard Space Shuttle Discovery at age 77 — still the oldest person to orbit the Earth.