The microgravity lab was a section aboard a Vissian starship.
In 2153, Calla headed up the microgravity lab on Drennik's starship, a position which didn't give her time for cooking. (ENT: "Cogenitor")
A microgravity lab, according to the Star Trek Encyclopedia (4th ed., vol. 2, p. 40), was a "
scientific facility used to study the effects of the extremely low levels of gravity
encountered in space