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| Smaller rotations can be accomplished with smaller pitches and yaws. Obviously, the same process applies to the derivatives, so it is possible to convert add spin in yaw, then spin in the pitch, then add spin in yaw again to create spin in the roll direction. Of course, this will be complicated by sun angle and the actual force vectors, and will also result in translations in relation to the array, so the exact manuever will need to be carefully computed in advance. Fortunately, server-sats think a lot faster than they move. |
Smaller rotations can be accomplished with smaller pitches and yaws. A 180 degree pitch, followed by a 180 degree yaw, causes a 180 degree roll. The same process applies to the derivatives, so it is possible to create rolling by adding spin in yaw, then spin in pitch, then add spin in yaw again to create spin in the roll direction. This will be complicated by sun angle and the actual force vectors, and will also result in translations in relation to the array, so the exact manuever will need to be carefully computed in advance. Fortunately, server-sats think a lot faster than they move. |
Roll control using pitch and yaw
For description purposes, imagine that the LCD thrusters provide orthogonal thrust, not angled thrust. We can make a 90 degree roll with a 90 degree yaw, a 90 degree pitch, and a 90 degree yaw again, like so:
Smaller rotations can be accomplished with smaller pitches and yaws. A 180 degree pitch, followed by a 180 degree yaw, causes a 180 degree roll. The same process applies to the derivatives, so it is possible to create rolling by adding spin in yaw, then spin in pitch, then add spin in yaw again to create spin in the roll direction. This will be complicated by sun angle and the actual force vectors, and will also result in translations in relation to the array, so the exact manuever will need to be carefully computed in advance. Fortunately, server-sats think a lot faster than they move.
The moment of inertia for flipping end over end is I = 0.25 M R2, while the moment of intertia for rotating flat is I = 0.50 M R2 . If the disk is anisotropically weighted, a roll may convert into a flip over time, anyway. This needs to be analyzed