Original NASA Employee First Day Cover – Feb 28, 1975

Original NASA Employee First Day Cover – Feb 28, 1975

• Original NASA Employee First Day Cover
• Dated: Feb 28, 1975
• Official First Day of Issue
• Pioneer Jupiter
• Marking United States Unmanned Space Accomplishments
• ~ Pioneer Jupiter (Pioneer 10) ~
• Mission - March 3, 1972 - April 27, 2002

Pioneer 10 (originally designated Pioneer F) is an American space probe, launched in 1972 and weighing 258 kilograms (569 pounds), that completed the first mission to the planet Jupiter. Thereafter, Pioneer 10 became the first of five artificial objects to achieve the escape velocity needed to leave the Solar System.

Pioneer 10 was assembled around a hexagonal bus with a 2.74-meter (9 ft 0 in) diameter parabolic dish high-gain antenna, and the spacecraft was spin stabilized around the axis of the antenna. Its electric power was supplied by four radioisotope thermoelectric generators that provided a combined 155 watts at launch.