# Propellant mass fraction

## Description

In aerospace engineering, the propellant mass fraction is the portion of a vehicle’s mass which does not reach the destination, usually used as a measure of the vehicle’s performance. In other words, the propellant mass fraction is the ratio between the propellant mass and the initial mass of the vehicle. In a spacecraft, the destination is usually an orbit, while for aircraft it is their landing location. A higher mass fraction represents less weight in a design. Another related measure is the payload fraction, which is the fraction of initial weight that is payload.It can be applied to a vehicle, a stage of a Vehicle or to a Rocket Propulsion System.

The propellant mass fraction is given by the formula shown here.

Related formulas## Variables

ζ | propellant mass fraction (dimensionless) |

m_{f} | final mass of the vehicle (kg) |

m_{0} | initial mass of the vehicle (kg) |