The term
micro-g environment (also
µg, often referred to by the term
microgravity) is more or less a synonym of
weightlessness and
zero-g, but indicates that
g-forces are not quite zero, just very small. The symbol for microgravity,
µg, was used on the insignias of
Space Shuttle flights
STS-87 and
STS-107, because these flights were devoted to microgravity research in
low Earth orbit.