Pressures 1. Vehicle point of view: designer wants minimum tank pressure 2. Engine point of view Must ensure that engine gets the minimum pressure it needs to operate. Cannot allow pressure loss from a minimal pressure in tank to put engine below min operating pressure. Pressures H2 line 600 psi out of turbine - 1000 psi (~I have a note 10,000 hours for turbine - can this be correct??) 300-400 psi in thrust chamber originally, now 600 psi in chamber. 40 firings (~to qualify??) Pressure changes Centaur - problems - when engine operates, high pressure from pumps to combustion chamber. Closing oxygen control valve creates high pressure between valves and the pump. Also, back pressure to vehicle tanks. Vehicle concern is not pressure force - it is the pressure differential between tanks. Must have greater pressure on the LOX side. (~ picture) Sloshing in the tanks cools the gas in the LOX tank and lowers pressure in the tank. This can disrupt the correct pressure differential between the tanks.