If gravity is not present, the speed of an object in one dimension is not subject to any gravitational force or acceleration. In the absence of external forces, the object would continue to move at a constant velocity indefinitely.
The maximum speed that an object can reach in this scenario would depend on the limitations imposed by other factors, such as the object's mass, its interaction with the medium (if any), or the presence of any other forces acting upon it. If we assume that there are no additional forces acting on the object, then its speed can theoretically reach any value as long as there are no constraints from external factors.
It's important to note that this answer assumes a simplified scenario with no external forces, which is not realistic in most physical situations. In reality, gravitational forces or other forces typically act on objects, influencing their motion.