Goals: Zond 1 was intended to be a Venus impact probe, but it wound up being an inert flyby that accomplished some science before contact was lost.

Accomplishments: The Soviets lost contact with the spacecraft about halfway through its journey, but not before making two major course corrections -- the first time such actions were performed on a Soviet interplanetary spacecraft. After Zond 1 flew by Venus at a range of about 100,000 km (62,000 miles), the Soviets published some data on cosmic-ray flux that Zond 1 had measured.