Pioneer 5:
Goals: Pioneer 5 was sent into a heliocentric orbit between Earth and Venus as a technology test. It also carried equipment to confirm scientists' theories of an interplanetary magnetic field.
Accomplishments:The spacecraft proved to be a successful test of technologies that would carry later missions in the series -- such as Pioneers 10 and 11 -- deep into the outer solar system. It also confirmed the existence of the interplanetary magnetic field.
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This spacecraft was initially intended to be sent to Venus, but the mission was changed to test new technologies.
