Editing Apollo 6 (section)

==Objectives==
{{for|a brief summary of events prior to [[Apollo 4]], the first test of the [[Saturn V]]|Apollo 4#Background}}
Apollo 6, the second test flight of the {{Featured article}}
[[Saturn V]] launch vehicle, was intended to send a [[command and service module]] (CSM) plus a Lunar Test Article (LTA), a simulated [[Apollo Lunar Module|lunar module]] (LM) with mounted structural vibration sensors, into a [[translunar trajectory|trans-lunar trajectory]], with the boost from orbit to trans-lunar velocity powered by the Saturn V's third stage, the [[S-IVB]]. That trajectory, although passing beyond the orbit of the Moon, would not encounter it. The CSM was to separate from the S-IVB soon after the burn, and the SM engine would then fire to slow the craft, dropping its [[apogee]] to {{convert|11,989|nmi|km|order=flip|sp=us}} and causing the CSM to return to Earth, simulating a "direct-return" abort. On the return leg, the engine was to fire once more to accelerate the craft to simulate conditions that the Apollo spacecraft would encounter on its return from the Moon, with a re-entry angle of −6.5 degrees and velocity of {{convert|36,500|ft/s|m/s|order=flip|sp=us}}. The entire mission was to last about 10 hours.{{sfn|Press Kit|p=3}}<ref name="lver">{{cite book |title=Saturn V Launch Vehicle Flight Evaluation Report - AS-502 Apollo 6 Mission |url=http://klabs.org/history/history_docs/jsc_t/apollo_06_saturn_v.pdf |access-date=July 7, 2013 |date=June 25, 1968 |publisher=NASA |id=MPR-SAT-FE-68-3}}</ref><ref name = "legacy">{{cite web|title=The Legacy of Apollo 6|url=https://www.nasa.gov/mediacast/the-legacy-of-apollo-6|date=April 4, 2021|accessdate=September 19, 2021|publisher=[[NASA]]}}</ref>
 
The mission was intended to test the Saturn V launch vehicle's ability to send the entire Apollo spacecraft to the Moon—in particular, to test the stresses on the LM and the vibration modes of the entire Saturn V with near-full loads.{{sfn|Orloff & Harland 2006|pp=204–206}} With the spacecraft having been qualified for crewed flight through the Apollo 4 mission (the first flight of the Saturn V), the focus was on fully qualifying the launch vehicle. Nominal completion of planned mission events through attainment of the initial parking orbit, and the restarting of the S-IVB to propel the [[space vehicle]] towards the planned distance, beyond the Moon's orbit, was deemed sufficient to fulfill Apollo 6's main objectives.{{sfn|Press Kit|p=1}}