Vanguard 1, the first solar powered artificial satellite, was the second artificial satellite successfully launched into Earth orbit by the United States.

Sputnik I and II were sent into orbit earlier by the Soviet Union, and Explorer 1 was the first satellite to be placed in orbit by the United States. All three satellites have since lost their orbits and have been destroyed while falling back into Earth’s atmosphere.

Small events are planned on March 17, 2008 to commemorate the mission of Vanguard 1.

The Naval Research Laboratory is planning a celebration, while the National Academy of Sciences has scheduled various seminars to mark the fiftieth anniversaries of the International Geophysical Year (1958) and Vanguard 1.

The pioneering efforts of Vanguard 1 showed that solar powered satellites are operable in space. Although communications with Vanguard 1 ended in May 1964, it continues to be optically tracked by astronomers and other scientists. Its position in space helps to determine positional data on the Sun and Moon, along with other positional data.

The U.S. Navy’s website “Vanguard I--the World's Oldest Satellite Still in Orbit” provides additional information on Vanguard 1.

NASA’s Goddard Space Flight Center website “Vanguard 1” also provides information on the satellite.

The launch of Vanguard 1 is shown, several times, at YouTube’s 4:36-minute video “Launch of Vanguard 1 (TV-4)” .