Date: 1 Jan 1959
NASA's famous insignia -- nicknamed "the meatball" -- was designed by an employee in 1959. The sphere represents a planet, the stars represent space, the red chevron is a wing representing aeronautics (the latest design in hypersonic wings at the time the logo was developed), and then there is an orbiting spacecraft going around the wing.
The meatball was designed by James Modarelli, who was head of the Lewis' Research Center's Reports Division in 1959.
Known officially as the insignia, NASA's round logo was not called the "meatball" until 1975, when NASA decided a more modern logo was in order and switched to "the worm" -- a red, stylized rendering of the letters N-A-S-A. NASA no longer uses the worm logo.