NOT KNOWN FACTUAL STATEMENTS ABOUT APOLLO4 BLUE PLUS

The S-IVB also continued to thrust in a very low stage by venting gaseous hydrogen, to keep propellants settled in their tanks and prevent gaseous cavities from forming in propellant feed traces. This venting also taken care of Risk-free pressures as liquid hydrogen boiled off from the gas tank. This venting thrust simply exceeded aerodynamic drag.