Ullage motors or Ullage engines are relatively small, independently-fueled rocket engines that may be fired to accelerate the rocket prior to main engine ignition, when the vehicle is in a zero-g situation. A rocket engine is a Jet engine that uses only Propellant mass for forming its high speed propulsive jet. Weightlessness is a phenomenon experienced by people during Free-fall.
By Newton's laws of motion, these motors give an acceleration that moves the main engine liquid fuel and oxidizer to the bottom of their tanks where they can be pumped and the ullage gas floats 'up' and away from the engine inlets. Newton's laws of motion are three Physical laws which provide relationships between the Forces acting on a body and the motion of the An oxidizing agent or oxidising agent (also called an oxidant, oxidizer or oxidiser) can be defined as either a Chemical compound Such motors were first invented by Soviet engineers for the Molniya interplanetary launch vehicle in 1960. Molniya-M Molniya 8K78 was a modification of the well-known R-7 Semyorka rocket and has four stages
The firing of the ullage motors is used during stage separation of rocket and/or stabilization of a rocket.
The four ullage motors of the Saturn V rocket used in the American Apollo program were located on the second stage. The Saturn V (pronounced 'Saturn Five' popularly known as the Moon Rocket was a multistage liquid-fuel expendable Rocket used by NASA 's In the third stage (known as S-IVB), there was a more general Auxiliary Propulsion System that also had ullage functions.
Ullage motors are also commonly employed on deep-space missions where a liquid rocket needs to do a burn after travelling for some time.
The terms ullage engine and ullage rocket are also used.
Ullage motors are typically very small; research shows that only milli-gee accelerations are needed to avoid excessive gas intake.
Some vehicles use other techniques to hold liquid at the inlet, as, once the main engines are lit, ullage motors are no longer required.
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References
A rocket engine is a Jet engine that uses only Propellant mass for forming its high speed propulsive jet. Ullage refers to the unfilled space in a container of liquid Etymology The word comes ultimately from the Latin oculus “eye” which was used in a figurative A rocket or rocket vehicle is a Missile, Aircraft or other Vehicle which obtains Thrust by the reaction of theDapyx Software network: MP3 Explorer | Ebook Manager | Zenithic