Space Propulsion - IAP/TU Wien
Space Propulsion - IAP/TU Wien
Space Propulsion - IAP/TU Wien
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<strong>Space</strong> <strong>Propulsion</strong><br />
Total impulse<br />
Total impulse is the total momentum gained during the burn time t b of a thruster<br />
definition<br />
I<br />
tb<br />
= ∫Tdt<br />
[ N.<br />
s]<br />
0<br />
When thrust is constant over time, or at least during thruster – on time intervals,<br />
total impulse can be written as<br />
I = T τ.<br />
τ τ<br />
τ<br />
= ⎛ dm ⎞<br />
∫Tdt<br />
= ∫ ⎜ ⎟Ve<br />
dt = Ve<br />
dt<br />
∫<br />
0 0 ⎝ ⎠<br />
0<br />
I dm = V . m<br />
e<br />
p<br />
m p … propellant mass used during mission time τ<br />
V e … exhaust velocity, assumed to be constant during mission