Editing Apollo 4 (section)

==Objectives==
The purpose of Apollo 4 (together with the Saturn{{nbs}}V's other uncrewed test flight, Apollo{{nbs}}6) was to qualify the launch vehicle, the Apollo spacecraft, and the ground systems, for the crewed lunar landing missions that would follow. In addition to being the first flight of the Saturn{{nbs}}V, Apollo{{nbs}}4 marked the first flight for two of its stages: the S-IC first stage and the S-II second stage (the S-IVB had flown as part of the Saturn{{nbs}}IB).{{sfn|Saturn V evaluation|p=xxxviii}}{{sfn|Orloff & Harland 2006|p=75}}

Objectives for the Apollo 4 mission were to gain flight data on the Saturn{{nbs}}V and spacecraft structural integrity and mutual compatibility, including on flight loads and during the separations as each Saturn{{nbs}}V stage was exhausted and was discarded. NASA also wanted data on subsystem operations, including the emergency detection subsystem, and sought to evaluate the Apollo CM's [[heat shield]] under conditions simulating a return from a lunar mission.{{sfn|Press Kit|p=1}} NASA was also seeking to test the restart capability of the S-IVB in space.<ref name="photoAnal" /> These objectives would all be achieved.{{sfn|Orloff & Harland 2006|pp=127–137}}