Start a new single player game...
1. Enter Creative Mode by going into the Inventory menu and pressing the Creative Mode button.
2. Place a stackable item (such as a thruster module) from the inventory menu into the hotbar.
3. Drop the item by dragging it from the hotbar into empty space. An icon representing the dropped item now appears in front of you.
4. Exit Creative Mode.
5. Pick up the item by running over it. It should appear in your inventory/hotbar and completely max out your carrying capacity. The item should still be floating in space.