The Anti-Gravity Sphere is a component of the Dark Vortex Future. It is a non-sentient device which Ecco must use to destroy barriers to advance through Black Clouds. The sphere reacts to Ecco's sonar, and, while not dangerous or harmful, if summoned while near a wall it can smash and kill Ecco fairly quickly. It serves no purpose other than to swallow up obstacles to advance Ecco through the level. Why and how it would have served the Vortex-kind remains an enigma.
Use as a kind of telepathic engine for a spaceship is but one of the conjectured purposes.