Sphere 41 was a Delphic Expanse sphere encountered on February 14, 2154 by Enterprise NX-01.
T'Pol determined that this sphere was a key to the sphere network's energy grid, and with Commander Trip Tucker, developed a means of destroying it using Enterprise's navigational deflector array. This plan was successful, and triggered a chain reaction, destroying all the spheres within the Delphic Expanse. The destruction of the spheres returned the Expanse to normal space, devoid of spatial anomalies. (ENT: "Countdown", "Zero Hour")