5.4 SYSTEMS EVAPORATING NONPROPELLANTS

This type of pressurization system has not been employed frequently. Two types of inert cryogenics could be considered applicable: liquid nitrogen and liquid helium. Both have definite disadvantages which would generally preclude their use in nonpropellant evaporation systems. The main disadvantages are their solubility in the propellants (nitrogen in liquid oxygen) and a storage temperature significantly lower than that of the propellants (liquid helium). The system design for this concept is similar to that of the propellant evaporation systems.