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

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S.3 Propulsion System Options
Spacecraft Propulsion System Options:
Spacecraft Propulsion Systems can be classified according to the type energy source. Both
space propulsion and auxiliary propulsion are performed by the following two main on-board
spacecraft propulsion system types:
Chemical Propulsion Systems:
The energy to produce thrust is stored in the propellant, which is released by chemical
reactions and the propellant is then accelerated to a high velocity by expanding it in
form of gas through a nozzle. Currently available chemical propulsion systems can be
categorized as either: hot gas or cold gas system.
Electric Propulsion Systems:
The energy to produce thrust is not stored in the propellant but has to be supplied from
outside by an extra power source, e.g. nuclear, solar radiation receivers or batteries.
Thrust is produced by:
- Expansion of hot gas (which is heated by electric current) in a nozzle,
- Accelerating of charged particles in electric or magnetic fields to high expulsion
velocities.