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| Pioneer 4 "Goldcraft" launch cover postmarked at Port Canaveral on March 3, 1959. After the launch of Luna 1 by the Soviet Union in January 1959, the United States launched its Pioneer 4 fly-by spacecraft on March 3, 1959. Pioneer 4 approached within 60,000 kilometers (37,300 miles) of the Moon, transmitting valuable data on lunar radiation levels before eventually entering a solar orbit. |
Pioneer 4 was launched on March 3, 1959, and successfully flew within 60,000 kilometers (37,300 miles) of the Moon the next day. The satellite was tracked for 82 hours, reaching a distance of 655,000 kilometers (407,000 miles) from Earth, which was a record at that time.
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| Photo: Dr. Wernher von Braun, John Casani, and Dr. James A. Van Allen give Pioneer 4 a final inspection before its assembly. |
Pioneer 4 was the first U.S. spacecraft to achieve solar orbit. It was the only successful lunar probe among 12 attempts made by the U.S. between 1958 and 1963; it wouldn't be until 1964 that Ranger 7 would exceed its success by accomplishing all of its mission objectives.
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| Photo: During a press conference on March 4, 1959, Dr. Homer J. Stewart announced that the Pioneer 4 probe had successfully passed the Moon and entered into an orbit around the Sun. |
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| Pioneer 4 launch cover featuring a Farley thermographic cachet, postmarked at Patrick Air Force Base on March 3, 1959. |
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| Photo: An illustration depicting the flight path of Pioneer 4, the solar satellite. |
(Reference from
Pioneer 4)
