There’s no gravity in space. On a planet like ours, down is always toward the center of gravity. Up is always the opposite of the center of gravity. Drop a ball, it goes down. Up is the opposite.
In space if you let go of a ball it stays where you let go of it (as long as you weren’t moving your hand, that is.)
Your personal sense of up and down is caused by your inner ear. In space, however, sometimes people feel sick because it feels like they’re falling all the time (and in fact, when in orbit you are falling all the time).