Early series of US Earth-orbiting satellites and their associated rocket launcher. Vanguard 1 was the second US satellite, launched on 17 March 1958 by the three-stage Vanguard rocket. Tracking of its orbit revealed that the Earth is slightly pear-shaped. The series ended in September 1959 with Vanguard 3.
The star depicts Liberia as a shining light. The blue canton symbolizes the dark continent of Africa. The stripes represent the 11 signatories to the Declaration of Independence. Effective date: 26 July 1847.