On October 29, 1998, the first American to orbit the Earth made history again. John Glenn became the oldest man to fly in space by serving as a payload specialist on STS-95 aboard the space shuttle Discovery.
The nine-day mission supported a variety of research, including the deployment of the Spartan Solar Observing Spacecraft, the Hubble Space Telescope orbital systems test platform and several microgravity experiments from NASA Glenn (then Lewis).
Glenn spent most of his time in space participating in investigations on the aging process. Scientists recognize several parallels between the effects of spaceflight on the human body and the natural changes that take place as a person ages. Glenn’s experiments were designed to test how his body responded to the microgravity environment. They focused on balance, perception, immune system response, bone and muscle density, metabolism, blood flow and sleep.