Velara III was a (previously believed) lifeless planet where the Federation had set up a terraforming station. It was revealed that Velara already had a silicon-based lifeform called Microbrains and the terraforming operation was unknowingly destroying them. The planet is close to the Pleiades Cluster, since that was what USS Enterprise-D was mapping, prior to arriving in 2364. (TNG episode: "Home Soil") The project was then abandoned and the planet quarantined by the Federation. (TNG novel: A Time to Sow)