The forgotten mission of Pioneer 5

摘要

Forty five years ago, in March of 1960, NASA launched a modest 94.8 pound sphere on a planetary trajectory toward the orbit of Venus. The objective of the Pioneer 5 mission was not the planet itself (Venus was not in position for an encounter), but rather a survey of environmental conditions in interplanetary space to demonstrate the feasibility of communicating with a spacecraft at great distances. At a time in the early Space Age when the farthest radio, barely beyond the Moon, the solar- powered Pioneer set a communication distance record of 22.5 million miles after surviving for three-and-a-half months after launch.