In space, an object like a shuttle will continue to move at a constant velocity even if it is no longer generating any force due to the principle of inertia.
The principle of inertia, which is one of Newton's laws of motion, states that an object at rest will remain at rest, and an object in motion will continue moving at a constant velocity in a straight line unless acted upon by an external force.
In the case of a shuttle in space, once it has been set in motion and reached a certain velocity, there is no significant external force to oppose its motion or bring it to a stop. In the vacuum of space, where there is very little air resistance or friction, the shuttle experiences negligible forces that could slow it down.
Without any significant external forces acting on the shuttle, there is no reason for its velocity to change. Therefore, it will continue to move at a constant velocity, maintaining its state of motion until an external force, such as thrust from its engines or the gravitational pull of another object, acts upon it and alters its velocity.