A launch vehicle is a part of a launch system carrying a payload up to orbit. Usually on Earth, but the same name would be used for Mars, where the difficulty of creating a launch vehicle is much smaller, due to lower deltaV requirements.
Launch vehicles are classed by NASA according to Low Earth Orbit payload (LEO) capability:
- Small-lift launch vehicle: < 2,000 kilograms (4,400 lb) - e.g. Vega
- Medium-lift launch vehicle: 2,000 to 20,000 kilograms (4,400 to 44,100 lb) - e.g. Soyuz ST
- Heavy-lift launch vehicle: > 20,000 to 50,000 kilograms (44,000 to 110,000 lb) - e.g. Ariane 5
- Super-heavy lift vehicle: > 50,000 kilograms (110,000 lb) - e.g. Saturn V
Launch cost economics
Launch cost economics is a complex subject, source of endless debates. We present a simplified analysis here, for transportation to LEO, using the following equation:
Pc = Payload cost ($/kg)
Pc = (De+Co*Vg+In+Vg*Vf*(Ma+Fu))/Pm*Vg*Vf where:
De = Development costs ; Research, management and testing. Safety requirements for crewed vehicles. Flight proofing.
Co = Construction of the vehicle ; Materials and manufacturing, person hours, testing.
Vg = Vehicles per generation ; Number of vehicles built per design generation.
In = Infrastructure ; Manufacturing plants, tooling and launch sites for a series of vehicles
Vf = Vehicle flights; Number of flights a vehicle can do.
Ma = Maintenance cost per flight; Clean up, repair, upgrades, fueling, set up on pad.
Fu = Fuel cost per flight
Pm= Payload mass (kg)
Environmental impact is not included as a cost but needs to be taken into account in the overall analysis. This parameter doomed fission pulsed propulsion and exotic fuels using fluorine, and might become an issue at high flight rates.