The S-IVB also continued to thrust at a low stage by venting gaseous hydrogen, to maintain propellants settled within their tanks and forestall gaseous cavities from forming in propellant feed lines. This venting also preserved Secure pressures as liquid hydrogen boiled off from the fuel tank. This venting thrust https://emilioppnkl.amoblog.com/not-known-facts-about-apollo4-plus-56118696