S.1 Spacecraft Propulsion Systems Chapter 1: Introduction to ...

S.5 Summary
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Selection process involves a variety of propulsion options, such as systems operated with
cold gas, liquid monopropellant and bipropellant, or some form of electric propulsion.
Primarily, propulsion systems have to meet mission impulse and velocity increment ∆v
requirements. Therefore, the evaluation of propulsion system performances is a primary
task in the selection process.
The ‘System specific Impulse’, Issp, allows a more accurate determination of the propulsive
performance of spacecraft propulsion systems than the commonly used ‘Thruster-specific
Impulse’, Isp, which only includes the propellant mass. To achieve low system mass, high
values for Issp are desired.
The prevailing goal of advanced propulsion is to enable cost efficient space missions and
extended exploration of the solar system up to interstellar missions.