List of artificial objects leaving the Solar System

In addition to these spacecraft, some upper stages and de-spin weights are leaving the Solar System, assuming they continue on their trajectories.

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.

[19] Solar escape velocity is a function of distance (r) from the Sun's center, given by where the product G Msun is the heliocentric gravitational parameter.

However, in cases where the spacecraft acquired escape velocity because of a gravity assist, the stages may not have a similar course and there is the extremely remote possibility that they collided with something.

The stages on an escape trajectory are: In addition, two small yo-yo de-spin weights on wires were used to reduce the spin of the New Horizons probe prior to its release from the third-stage rocket.

[24][better source needed] Pioneer 11 gained the required velocity to escape the Solar System in its subsequent encounter with Saturn.

Thus the only objects to date to be launched directly into a solar escape trajectory were the New Horizons spacecraft, its third stage, and the two de-spin masses.

In 1990, the solar probe Ulysses was launched towards Jupiter in order to reach a high-inclination heliocentric orbit over the Sun's poles; the spacecraft was shut down in 2008.

Spacecraft that have left or are about to leave the Solar System are depicted as square boxes
Plot of Voyager 2 ′s heliocentric velocity against its distance from the Sun, illustrating the use of gravity assist to accelerate the spacecraft by Jupiter, Saturn and Uranus, and finally its encounter with Neptune's Triton. Very massive planets attract spacecraft towards them, through the gravitational force; this force accelerates the spacecraft. If the spacecraft is not on a collision trajectory with the planet, and the spacecraft is travelling faster than the escape velocity of the planet, the spacecraft will travel past the planet gaining speed from the gravitational acceleration; this is called a gravity assist (or “gravitational slingshot”).
A Star-48 rocket motor like the one used to launch the New Horizons probe
Voyager 1 and close encounters of the Sun with other stars in the next 100,000 years.