Normally it is seen that objects with more mass accelerates during their free fall than objects having smaller mass. The frictional force of air also known as the drag force get negated by the massive object and so the object gets acceleration during the free fall. If the mass of the object is small, then the frictional force or the drag will slow the object during free fall. In case of vaccum the mass of the object does not matter as there is no drag or frictional force working against it. The objects with greater or smaller mass will then free fall with the same speed in the vaccum.