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

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S.9 Type of Propulsion Systems
The basic propulsion mathematical formulas presented have to be further expanded for
today's commonly used 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.
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)
- accelerating of charged particles in electric or magnetic fields to high expulsion
velocities.