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Space Propulsion - IAP/TU Wien

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

Example 6: One-Axis Maneuver<br />

Find the minimum time required for a spacecraft to perform a 90-deg turn about the z axis<br />

with two thrusters if the spacecraft has the following characteristics:<br />

Mass of S/C = 500 kg,<br />

Radius of S/C = 0.75 m<br />

Moment of inertia about the z axis ≅(2/5)M S/C.<br />

L 2 = 112.5 kg.m 2<br />

Moment arm = 0.75 m<br />

Thrust of each engine = 10 N<br />

and<br />

Θ m<br />

= π/2 = 1.5708 rad<br />

t<br />

2. Θ<br />

I<br />

m v<br />

min<br />

= =<br />

=<br />

nFL<br />

2*1.5708*112.5<br />

2*10*0.75<br />

4.854<br />

s<br />

How much propellant was consumed by the maneuver if I sp<br />

= 1900 m/s ?<br />

nFt<br />

m 2 * 2 *10 * 4.854<br />

m<br />

p<br />

= 2 =<br />

= 0. 102<br />

I 1900<br />

sp<br />

kg

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