List of artificial objects leaving the Solar System

Several space probes and the upper stages of their launch vehicles are leaving the Solar System, all of which were launched by NASA. The borders of the Solar System are usually defined by the Heliopause diameter at about 120 astronomical units (AU; one AU is roughly the average distance between Earth and the Sun: 150 million kilometers (93 million miles)). Three of the probes, Voyager 1, Voyager 2, and New Horizons, are still functioning and are regularly contacted by radio communication, while Pioneer 10 and Pioneer 11 are now derelict. In addition to these spacecraft, some upper stages and de-spin weights are leaving the Solar System, assuming they continue on their trajectories.

These objects are leaving the Solar System because their velocity and direction are taking them away from the Sun, and at their distance from the Sun, its gravitational pull is not sufficient to pull these objects back or into orbit. They are not impervious to the gravitational pull of the Sun and are being slowed, but are still traveling in excess of escape velocity to leave the Solar System and coast into interstellar space.

Planetary exploration probes

Pioneer 10 – launched in March 1972, flew past Jupiter in 1973 and is heading in the direction of Aldebaran (65 light years away) in the constellation of Taurus. Contact was lost in January 2003, and it is estimated to have passed 138 astronomical units.

Pioneer 11 – launched in April 1973, flew past Jupiter in 1974 and Saturn in 1979. Contact was lost in November 1995, and it is estimated to be at 116 AU. The spacecraft is heading toward the constellation of Aquila, northwest of the constellation of Sagittarius. Barring any incident, Pioneer 11 will pass near one of the stars in the constellation in about four million years.