Apollo 6とは 意味・読み方・使い方

Apollo 6, launched on April 4, 1968, was the Apollo program's second and last A type mission—unmanned test flight of its Saturn V launch vehicle. It was intended to demonstrate full lunar injection capability of the Saturn V, and the capability of the Command Module's heat shield to withstand a lunar re-entry. Fuel line failures in several Saturn V second and third stage engines prevented it from achieving lunar injection, but it was able to get close to lunar return velocity by using the Apollo spacecraft's engine, as was done on Apollo 4, the first Saturn V test. Despite the engine failures, the flight nonetheless provided NASA with enough confidence in the Saturn V to use it for manned launches. And since Apollo 4 had demonstrated the heat shield at full lunar re-entry velocity, a potential third unmanned flight was cancelled.