To protect the first astronauts from sudden pressure loss, NASA modified high - altitude jet - aircraft pressure suits from the US Navy. (businessinsider.com)
Astronauts weren't venturing outside, so they only wore an emergency ejection escape suit, which (like the Mercury suit) was a modified version of a US Air Force high - altitude pressure suit. (businessinsider.com)
But there are solid pieces of research within Constellation that would be smart to save, such as the development of updated pressure suits. (discovermagazine.com)