The shape of a drop lying on a non-wettable solid substrate and the phenomenon of a drop jump from the substrate during the transition to weightlessness are investigated experimentally, theoretically and numerically. A mechanical model of the jump of the drop is proposed. The shape of a lying drop is calculated, and it is shown that the height of the drop depends on the volume of the drop nonmonotonically. The radius of the contact area of the drop with the substrate is calculated as a function of the volume. A formula describing this dependence is proposed. Theoretical estimations of the speed of the drop jump for small and large sizes of the drop are made. It is proved that there is a minimum size of the bouncing drop: if the size of a drop is less than this minimum size, then a jump of the drop is impossible. The speeds of jump are calculated numerically for arbitrary sizes of drop. Experimental results are in satisfactory agreement with theoretical and numerical results.