final uncrewed test flight of the United States Apollo program
via Wikipedia infobox
Apollo 6 (April 4, 1968), also known as AS-502, was the third and final uncrewed flight in the United States' Apollo program and the second test of the Saturn V launch vehicle. The Saturn V's utilization during the mission qualified it for use during human spaceflight, and it was used beginning on Apollo 8 in December 1968.
Apollo 6 was intended to demonstrate the ability of the Saturn V's third stage, the S-IVB, to propel itself and the Apollo spacecraft to lunar distances. Its components began arriving at the Kennedy Space Center in early 1967. Testing proceeded slowly, often delayed by testing of the Saturn V intended for Apollo 4—the inaugural launch of the Saturn V. After that uncrewed mission launched in November 1967, there were fewer delays, but enough so that the flight was postponed from March to April 1968.
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