Explore: Ullage

Ullage or headspace is the unfilled space in a container, particularly with a liquid. The word ullage comes from the Latin word oculus, used by the Romans

Ullage motors (also known as ullage engines or ullage rockets) are relatively small, independently fueled rocket engines that may be fired prior to main

fully filled, and during use, there is a space above the fuel, called the ullage, that contains evaporated fuel mixed with air, which contains the oxygen

Ullage (from the French ouillage) is a winemaking term that has several meanings but most commonly refers to the headspace of air between wine and the

open during flight when the ullage (empty space) pressure of the liquid hydrogen tank reaches 38 psi (260 kPa) or the ullage pressure of the liquid oxygen

As propellant is drained from its tank, something must fill the vacated ullage space to maintain pressure inside the tanks. This is for two reasons: first

control authority is provided by cold gas thrusters fed with residual ullage gas. Four perpendicular vents are located within the interstage. Additional

the gas can. This last condition causes a rich vapor concentration in the ullage (the unfilled volume) of the gas can, and a discharge from the can to the

small Auxiliary Propulsion System (APS) thruster modules were added as ullage motors for restarting the J-2 engine and to provide attitude control during

begin to dry out, it can allow oxygen to enter the bottle, filling the ullage space and possibly causing the wine to spoil or oxidize. Excessive humidity