Sphere 1 was a Delphic Expanse sphere encountered in September 2153 by Enterprise NX-01.
It was being used by Osaarian raiders as a base. It was located in the Orassin distortion field of the Delphic Expanse. (ENT: "The Xindi", "Anomaly (ENT)")
The following year, it was destroyed along with the entire sphere network as the Orassin distortion field, along with the entire Delphic Expanse, reverted to its natural state. (ENT: "Zero Hour")