1975 10¢ Pioneer 10
Issue Date: February 28, 1975
City: Mountain View, California
Printed By: Bureau of Engraving and Printing
Printing Method: Lithographed, engraved
U.S. #1556 commemorates the Pioneer 10 space probe’s study of the planet Jupiter. An unmanned space vehicle, Pioneer 10 relayed information about weather, atmosphere, and radiation. It also passed within 81,000 miles of the planet Jupiter on December 3, 1973. One year later, Pioneer 11 narrowed the distance to 27,000 miles.