In flight, any rocket will rotate about its
center of gravity,
a point which is the average location of the mass of the rocket.
We can define a three dimensional coordinate system through the
center of gravity with each axis of this coordinate system perpendicular
to the other two axes.
We can then define the
of the rocket by the amount of
rotation of the parts of the rocket along these principal axes.
The pitch axis is perpendicular to the rocket centerline. A
is an up or down movement of the nose of the rocket as shown in the
The pitching motion is being caused by the deflection of the
nozzle of the rocket. Such a rotation
of the nozzle is called
gimballing the nozzle
and the motion causes the
to be inclined to the roll axis. Since the center of gravity
is located on the roll axis, the thrust vector generates a
about the center of gravity which
causes the rocket to rotate.
The Space Shuttle executes a pitch maneuver during its ascent
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