Sphinx (satellite)

Sphinx is the designation of an American test satellite. The Sphinx satellite was the payload for the first Titan IIIE Centaur rocket. The Helios, Viking and Voyager space probes were later launched using this rocket.

It was launched on February 11, 1974 from a Titan IIIE Centaur, however a failure in the second stage did not allow it to reach Earth orbit. It was launched with the Viking Dynamic Simulator.

SPHINX stood for Space Plasma High Voltage Interaction Experiment. It was designed to test high-voltage equipment in outer space.