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

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S.3 Propulsion System Selection
In the selection process, the most fundamental criterion for the propulsion system to be
selected is its achievement of the mission impulse and velocity increment ∆v requirements.
Therefore, an important consideration for the selection of a suitable propulsion system is
the trade-off between its velocity increment capability and propulsion system mass.
The mass of propulsion systems can be determined with help of the overall Propulsion
System Mass Fraction (see Chapter 2)
The Curves of mPS/mS/C, plotted as a function of ∆v for different actual spacecraft
propulsion system designs with typical values of Isp (ve) and Issp, give the first and most
important indication for the selection of propulsion systems.
For a more detailed performance evaluation, the software program “Issp” can be used.
It is based on the evaluation of the ‘System-specific Impulse’, Issp. It can be
downloaded from Swedish Space Corporation Web Site.
When suitable spacecraft auxiliary propulsion systems are selected, a refinement of the
selection is carried out. This process takes into consideration additional parameters such
as cost, complexity, operability and reliability of the system (more selection criteria).
This table summarizes advantages and disadvantages as well as the basic characteristics
of different propulsion systems.