zeroG

ZeroG, often written zero-G, is a term used to describe weightlessness or microgravity—the condition in which objects appear to have no effective weight. It is not a true absence of gravity; gravitational forces remain, but the contact force felt by a body is effectively zero.

In orbital spaceflight, spacecraft and everything inside are in free fall toward Earth while following a curved path, producing a sustained microgravity environment. Inside the cabin, astronauts experience weightlessness as the hull and their bodies fall alongside the spacecraft.

Microgravity can be achieved in several ways: natural microgravity in orbit; artificial microgravity produced during parabolic flight aboard modified aircraft, which yields brief periods of weightlessness (typically around 20 seconds per parabola); and neutral buoyancy facilities used for training. Drop towers offer short free-fall intervals as well.

Applications include scientific research in fluid dynamics, combustion, and materials science; biological experiments; astronaut and hardware training; and testing of equipment. Parabolic flights and related programs are sometimes marketed to the public as experiences of weightlessness, and organizations can provide commercially operated zero-G experiences.

Limitations include the brief duration of weightlessness in parabolic flights, residual accelerations from vehicle motion, and the need for specialized safety protocols. The term microgravity reflects that gravity is not actually eliminated; rather, its effects are not felt due to free-fall conditions.