The Solar and Heliospheric Observatory (SOHO), a project of international cooperation between the European Space Agency (ESA) and the National Aeronautics and Space Administration (NASA), was launched on December 2, 1995, and began full scientific operation on February 14, 1996. It obtains a continuous, uninterrupted view of the Sun from its halo orbit around the point 1.5 million kilometers (930,000 mi) sunward from the Earth, where the gravitational forces of the Earth and the Sun balance each other. The spacecraft orbits this equilibrium point to keep Earth-based tracking telescopes from looking directly at the Sun.