4¢ Echo I
Issue Date: December 15, 1960
City: Washington, D.C.
Printed by: Bureau of Engraving and Printing
Printing Method: Rotary Press
Perforations: 11 x 10 1/2
Color: Deep violet
U.S. #1173 honors Echo I, the world’s first passive communication satellite. The stamp shows a satellite orbiting earth while emitting radio waves.
Echo I, the world’s first passive communications satellite, was placed in orbit around the Earth on August 12, 1960. Echo I was a metalized balloon satellite that served as a passive reflector of microwave signals. Signals were sent from one location on Earth, bounced off the satellite, and then received at another point on Earth. These included telephone, radio, and television signals. The satellite also helped in calculations of atmospheric density and solar pressure.
After almost eight years in orbit, Echo I reentered Earth’s atmosphere and burned up on May 24, 1968.