Is rotational motion conditioned to a central force? We know rotational motion as a combination (a resultant) of two effects the tangential velocity and a centripetal force. Does rotational motion turn into linear motion at the same instance this centripetal force goes absent, and that rotational motion can't be a natural motion caused by one single effect, and linear motion is the only (raw) motion present in the universe?
We take an example, a spacecraft going to the moon (or anywhere into outer space). That spacecraft will leave the earth's atmosphere, and continue to move in a spiral motion outwards, increasing in radius, due to the momentum acquired by the earth's rotation. 
At some point that spacecraft should lose (if I'm correct) this rotational motion and shoot into a straight line, tangent to the last circle whose radius the distance from the earth's center. That's because the gravity (centripetal force) is no longer an acting force. Can this be true??
There's also a scene from the movie "Gravity" I didn't quite absorb. The astronaut keeps moving around when they separate from a rotating object and continue to move that way, (very famous scene in the trailer), is this accurate?
 A: The only force in acting on bodies in circular motion is the centripetal force, equal to $$F=\frac{mv^2}{r}$$ The centripetal force acts to the centre of the rotating body; there is no such thing as a tangential force. Also, gravity acts over infinite range, so the spacecraft will always have the Earth's gravitational field acting on it. If however, the centripetal force is abruptly removed (such as when a string attached to a tennis ball breaks when turned around), the body will follow the tangent to the circle at the moment the force was removed. 
As for the scene in Gravity, this was correct, because there is no friction (air resistance) to slow down, or stop the rotation.
A: As the spacecraft leaves the Earth, it will immediately go into a
straight motion if no force is acting on it. Its linear momentum may
be composed of linear momentum inherited from Earth rotation
(imparting a velocity to objects on its surface) and possibly other
sources of linear momentum that made it leave the planet. Any angular
momentum it may have (inherited from Earth, or otherwise) will only
result in the spacecraft rotating around its own center of mass.
However there is at least one force acting on the spacecraft: Earth
gravity. Its effect will be to bend the trajectory (assuming it is not
going straight up) into an ellipse, a parabola or a hyperbola,
depending on the velocity of the spacecraft.
There is no spiral motion.
When you let go of a rotating body, you shoot immediately into a
straight line, along a tangent, because the centripetal force is
gone. That is correct. However it is a straight line only if no other force is
acting, else the trajectory may be modified by this other force.
Regarding the film Gravity, there were a few instances when I wondered
about the correctness of the physics. But things go too fast to really
analyze the situation, and I do not have it on DVD. What you describe
does not seem very physical, but I do not recall it: separated from
the rotating body, the astronaute should go in a straight line (as I
said above).  This straight line is only a local approximation as the
astronaut will be on an elliptic orbit because of Earth gravity.
Actually Earth gravity was there from the beginning but could be
ignored as a first approximation when analyzing a local event taking
place in free fall.
Your statement about rotational motion (or angular momentum) being
only a special case of linear motion (linear momentum) is actually
wrong. But that might take too long to explain, and I am not sure I
would do it adequately.
