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

S.11 Electrical Propulsion
- 18-
An Electric Propulsion system is a mass expulsion system in which electric energy is used to
create or augment the kinetic energy in the expelled mass. Consequently electric power will be
of main interest in the performance evaluation of such systems.
Kinetic Energy of Ejected Matter
Power of the Jet
Power Input
1 2
E jet = m pve
[Ws]
2
dE 1 o
jet 2 ve
P jet = = mve
= F
dt 2 2
2 P o
jet ve
ve
P = = m = F
η 2η
2η
where η is the power conversion efficiency.
[W]
[W]