Velara Base, a terraforming station
A terraforming station was a type of fixed installation used to control and monitor the terraforming of a planet or moon. They could be operated by as few as four terraformers at a time.
The Velara Base was a terraforming station operating on Velara III until 2364, when the project was abandoned due to the presence of indigenous sentient life forms. (TNG: "Home Soil")
Numerous terraforming stations were present on Venus as of 2371. (DS9: "Past Tense, Part I")