Artifact: Regulator Assembly, Helium Pressure, Reaction Control, Apollo Service Module, Block II

Reaction Control System (RCS) Helium Pressure Regulator assembly manufactured by Fairchild Stratos Corp (Western Division) for the Apollo Service Module (Service Propulsion System), Reaction Control System pressurization system under NASA contract NAS9-150 for North American Aviation (NAA). The dual, series configured regulators (produced 1965) received gas from the SPS helium tank isolation valve and reduced ambient tank pressure of 4150 PSIA to approx 220 PSIA (nominal) before forwarding to the downstream RCS check valve (see RCS Check Valve description which precedes this entry). Each assembly incorporates two (primary and secondary) regulators connected in series. If the primary regulator fails open, the secondary regulator will maintain slightly higher but acceptable pressures. Diagram to the left depicts functional relationship/location of regulator in the RCS system.