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Space Propulsion - IAP/TU Wien

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1 – axis maneuvre, cont‘d<br />

<strong>Space</strong> <strong>Propulsion</strong><br />

total angle of rotation is<br />

rotation during coasting is<br />

Θ m<br />

= Θ (accelerating) + Θ (coasting) + Θ (braking)<br />

Θ = ωtc<br />

the coasting rotation angle is<br />

Θ =<br />

nFL<br />

t<br />

I<br />

v<br />

b<br />

t<br />

c<br />

ω =<br />

nFL<br />

I<br />

v<br />

t<br />

b<br />

total rotation during acceleration, coasting and braking is<br />

Θ<br />

m<br />

⎛ nFL<br />

= 2<br />

⎜ t<br />

⎝ 2I<br />

v<br />

2<br />

b<br />

⎞ nFL<br />

⎟ + t<br />

⎠ I<br />

v<br />

b<br />

t<br />

c<br />

=<br />

nFL<br />

I<br />

v<br />

2<br />

( 2t<br />

+ t t )<br />

b<br />

b<br />

c<br />

Θ =<br />

nFLt<br />

2I<br />

v<br />

2<br />

b<br />

maneuver time is<br />

t m = t C + 2t b<br />

accel.<br />

minimum rotation time is a fully powered<br />

maneuver with zero coast time<br />

t<br />

min<br />

= 2t<br />

b<br />

=<br />

2. Θ<br />

m<br />

I<br />

nFL<br />

v<br />

thrust level required for each thruster<br />

at given minimum rotation time<br />

F<br />

Θ m v<br />

2<br />

min<br />

I<br />

= 2<br />

nLt<br />

propellant required for a one-axis<br />

maneuver is twice the single burn consumption<br />

m<br />

p<br />

nFt<br />

b<br />

= 2 =<br />

I<br />

sp<br />

nFt<br />

I<br />

sp<br />

min<br />

nFt<br />

b<br />

m<br />

p<br />

= =<br />

I<br />

sp<br />

H<br />

LI<br />

sp

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