A rocket blasts off from the Earth on its way to the moon. As the rocket travels, it loses mass due to burning fuel and ejecting stages of the rocket. When the mass of the rocket has been reduced to one-half of its original mass it has traveled a distance equal to the radius of the Earth away from the surface of the Earth, where it took off. At this point, how does the gravitational force between the rocket and the Earth compare to the gravitational force at lift-off?