Microgravity is the condition experienced by objects in freefall orbit around Earth, where the apparent gravitational acceleration is reduced to roughly one-millionth of that at Earth's surface. Despite the common term "zero gravity," objects in LEO still experience about 90% of Earth's surface gravity; the sensation of weightlessness results from continuous freefall, not the absence of gravity.
Microgravity fundamentally alters physical processes: convection is eliminated, sedimentation stops, surface tension dominates fluid behavior, and crystal growth occurs without gravity-driven defects. These effects enable unique manufacturing opportunities including higher-purity fiber optics, more uniform pharmaceutical crystals, superior semiconductor wafers, and novel metal alloys. The ISS has served as the primary microgravity research platform, and commercial stations are being designed with ISM as a core revenue stream.