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Specific impulse should not be confused with energy efficiency, which can decrease as specific impulse increases, since propulsion systems that give high specific impulse require high energy to do so. [3] Specific impulse should not be confused with total thrust. Thrust is the force supplied by the engine and depends on the propellant mass flow ...
Using liquid methane and liquid oxygen as propellants is sometimes called methalox propulsion. [19] Liquid methane has a lower specific impulse than liquid hydrogen, but is easier to store due to its higher boiling point and density, as well as its lack of hydrogen embrittlement. It also leaves less residue in the engines compared to kerosene ...
A liquid-propellant rocket or liquid rocket uses a rocket engine burning liquid propellants. (Alternate approaches use gaseous or solid propellants.) Liquids are desirable propellants because they have reasonably high density and their combustion products have high specific impulse (I sp). This allows the volume of the propellant tanks to be ...
Solid fuel rockets have lower specific impulse, a measure of propellant efficiency, than liquid fuel rockets. As a result, the overall performance of solid upper stages is less than liquid stages even though the solid mass ratios are usually in the .91 to .93 range, as good as or better than most liquid propellant upper stages.
Nitrous oxide fuel blend propellants are a class of liquid rocket propellants that were intended in the early 2010s to be able to replace hydrazine as the standard storable rocket propellent in some applications. In nitrous-oxide fuel blends, the fuel and oxidizer are blended and stored; this is sometimes referred to as a mixed monopropellant.
For example, injecting a small amount of liquid hydrogen into a kerosene-burning engine can yield significant specific impulse improvements without compromising propellant density. This was demonstrated by the RD-701 achieving a specific impulse of 415 seconds in vacuum (higher than the pure LH2/LOX RS-68 ), where a pure kerosene engine with a ...
Storing liquid propellant may pose attitude control issues due to the sloshing of fuel in its tank. When choosing a propellant, a high specific impulse, and a high specific impulse per unit volume of propellant should be considered. [3] Overview of the specific impulses of propellants suitable for a cold gas propulsion system:
The most common use of monopropellants [3] is in low-impulse monopropellant rocket motors, [4] such as reaction control thrusters, the usual propellant being hydrazine [5] [6] which is generally decomposed by exposure to an iridium [7] [8] catalyst bed (the hydrazine is pre-heated to keep the reactant liquid).