From 0.81 to 1.02 g / ml
Highly concentrated hydrogen peroxide
43 ° C.
RP -1 ( Rocket Propellant abbreviation for 1 Refined Petroleum initially 1) is a kerosene- like liquid hydrocarbon mixture for the operation of rocket engines. RP- 1 was developed in the United States.
RP -1 was developed from the jet fuel JP- 4 by this was distilled again to win the highest- aggressive least Ingredients with the highest calorific value as rocket fuel.
The liquid substance at room temperature, consists mainly of branched and polycyclic hydrocarbons with small amounts of olefins, aromatics, and linear alkanes, which can polymerize the one hand and on the other hand, in long-term storage at the temperatures reached in the engine area. The desired and partially synthetic molecules contain about twelve carbon atoms. These molecules cause the fuel has a high flash point and good lubricity of engine components and has a long shelf life.
In the manufacture of the fuel is taken to keep the sulfur content is extremely low, since sulfur-containing combustion residues to premature wear and failure of the drive would result in rocket engine combustion chambers. In addition, sulfur compounds would aid the polymerization of fuel constituents and increase the risk of default of the manufactured with very low mechanical tolerances engines over charge. Due to the very low content of aromatics and alkenes, the substance is significantly less toxic than, say, gasoline and also has an equally significantly lower carcinogenic potential than hydrazine.
Can be made on the basis of this fuel oil from any source theory, in practice only a few high quality varieties are used. This and the low demand lead to when compared to conventional aviation fuels or other oil product users much higher price. RP -1 is standardized in U.S. military standard, " MIL -DTL- 25576D ".
Comparison with other rocket propellants
Compared to the fuel combination of liquid hydrogen - liquid oxygen (LOX -H2), the combination of RP -1 with respect to the mass of oxygen produce not as much thrust as the LOX - H2 combination, as their specific impulse is lower. Are offset by the advantages of much higher density of RP -1, so that, based on the volume of the combination with RP -1 can deliver more thrust. The relatively lower specific impulse due to the fact that the combustion products of RP -1 such as carbon dioxide (CO2), carbon monoxide (CO ), water ( H2O), and unreacted hydrocarbons, on average heavier than the gases, of the implementation of a fat mixture hydrogen with oxygen occur (H2O and H2). Further energy from the combustion of RP- 1, which is lost to the thrust producing a step in the Strukturoszillationen of the unburned hydrocarbons.
RP -1 is easier to use than liquid hydrogen, since no refrigeration is required, even when cooled in the Soviet and later Russian space of the fuel to further increase the density partly by exploiting the already existing hydrogen infrastructure.
As compared to the fuel combination hydrazine - nitrogen tetroxide is RP -1 substantially non-toxic, cheaper and with the oxidizer provides oxygen slightly higher specific impulse. For the density of hydrazine is slightly higher with nitrogen tetroxide.
Outside the United States, similar hydrocarbon -based fuels were developed. In the Soviet Union / Russia, there have been several oil -based and for a little more power in the 1980s with a synthetic Syntin even rocket fuel.
These fuels are burned usually together with liquid oxygen ( LOX) in the engines. Was RP -1 and is used inter alia in the types of rockets Atlas, Delta I - III, Saturn, Titan I and the Falcon. The Energia, Soyuz and Zenit rocket use similar fuels according to Russian standards. Were used, and these fuels are doing both in boosters ( ex. at the Energia ), as well as the fuel of the first stage ( ex. Saturn I, Saturn IB and Saturn V ) and upper level ( ex. Falcon series). The Black Arrow include an undefined kerosene came up with 85 % hydrogen peroxide as the oxidant used. This combination has but a worse specific impulse than RP-1/LOX is for hypergolic.
Is fed into the combustion chamber of the fuel from the pressurized tank via turbo pumps, the pressure must be generated by a separate pressure system which operates, for example, helium or nitrogen.
As part of the engine operation, some constraints must be observed. Liquid propellant rocket engines are for multiple ignitions (eg, on test stands and later in the flight ) was constructed, which can lead to problems if fuel remaining residues polymerize or coke into lines by the heat. These effects are counteracted by the careful fuel synthesis and cooling the conveyor system. On the other hand, fine carbon black or graphite deposits in the combustion chamber and the nozzle is not necessarily undesirable, since they form a thermal insulation layer and as the heat flow into the engine material can reduce a factor of about 2 microns.