We can see from table A.4.2.2.4.1 that for our four types of propellants (cryo, storable, hybrid, and solid) specific impulse does not vary greater than ten seconds, with the exception of liquid oxygen / liquid hydrogen. Due to great variation between liquid hydrogen / liquid oxygen and the other cryogenic fuels, we specifically chose liquid oxygen / liquid hydrogen as our cryogenic fuel for Model Analysis simulations. Selection for the other three systems required more analysis. Generally speaking, the cost of the propellant will be negligible in comparison to the cost of the engine and sub systems of the launch vehicle. In modern rocket design, most propellants are manufactured in bulk quantities which tend to limit costs. However, certain propellants, regardless of propellant price, can be extremely expensive due to the handling costs associated with their use. The main qualities we consider in the selection of the four propellants are the costs of equipment, personnel, and design alterations associated with the propellant characteristics. Some of the main considerations are: Highly Pressurized Propellants Low Temperature Propellants (cryogenics) Toxicity Volatile Nature Highly pressurized propellants require stronger, and thus, thicker tanks. These thicker tanks are heavier and more costly which makes them detrimental to our design. Propellants under high pressure also pose a safety hazard as they are less stable. Low temperature propellants pose a problem due to the tank, piping, and engine requiring insulation against the frigid temperatures. This also demands additional weight and cost associated with the insulation. Additional person hours are needed to fill the launch vehicle due to precooling the lines. A potential risk associated with cryogenic systems is boil-off leading to over pressurization of the fuel tanks and pressurant lines. This requires the addition of a bleed system to prevent explosion which increase complexity and cost.
We can see from table A.4.2.2.4.1 that for our four types of propellants (cryo, storable, hybrid, and solid) specific impulse does not vary greater than ten seconds, with the exception of liquid oxygen / liquid hydrogen. Due to great variation between liquid hydrogen / liquid oxygen and the other cryogenic fuels, we specifically chose liquid oxygen / liquid hydrogen as our cryogenic fuel for Model Analysis simulations. Selection for the other three systems required more analysis. Generally speaking, the cost of the propellant will be negligible in comparison to the cost of the engine and sub systems of the launch vehicle. In modern rocket design, most propellants are manufactured in bulk quantities which tend to limit costs. However, certain propellants, regardless of propellant price, can be extremely expensive due to the handling costs associated with their use. The main qualities we consider in the selection of the four propellants are the costs of equipment, personnel, and design alterations associated with the propellant characteristics. Some of the main considerations are: Highly Pressurized Propellants Low Temperature Propellants (cryogenics) Toxicity Volatile Nature Highly pressurized propellants require stronger, and thus, thicker tanks. These thicker tanks are heavier and more costly which makes them detrimental to our design. Propellants under high pressure also pose a safety hazard as they are less stable. Low temperature propellants pose a problem due to the tank, piping, and engine requiring insulation against the frigid temperatures. This also demands additional weight and cost associated with the insulation. Additional person hours are needed to fill the launch vehicle due to precooling the lines. A potential risk associated with cryogenic systems is boil-off leading to over pressurization of the fuel tanks and pressurant lines. This requires the addition of a bleed system to prevent explosion which increase complexity and cost.
Report_Section_7.docx