List of artificial objects leaving the Solar System

• Pioneer 10 – launched in 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 (AU; one AU is roughly the average distance between Earth and the Sun: 150 million kilometers (93 million miles)). • Pioneer 11 – launched in 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. • Voyager 2 – launched in August 1977, flew past Jupiter in 1979, Saturn in 1981, Uranus in 1986, and Neptune in 1989. The probe left the heliosphere for interstellar space at 119 AU on November 5, 2018. Voyager 2 is still active. It is not heading toward any particular star, although in roughly 40,000 years it should pass 1.7 light-years from the star Ross 248. If undisturbed for 296,000 years, Voyager 2 should pass by the star Sirius at a distance of 4.3 light-years. • Voyager 1 – launched in September 1977, flew past Jupiter in 1979 and Saturn in 1980, making a special close approach to Saturn's moon Titan. The probe passed the heliopause at 121 AU on August 25, 2012, to enter interstellar space. Voyager 1 is still active. In about 40,000 years the star Gliese 445 (AC +79 3888) and the Sun will fly past each other at a distance of 3.45 light-years, after being currently 17.6 light-years from each other, with Voyager 1 coming as close as 1.6 light-years to Gliese 445 at that time. • New Horizons – launched in 2006, the probe flew past Jupiter in 2007 and Pluto on July 14, 2015. It flew past the Kuiper belt object 486958 Arrokoth on January 1, 2019, as part of the Kuiper Belt Extended Mission (KEM). On April 17, 2021, it reached a distance of 50 AU from the Sun. Although other probes were launched first, Voyager 1 has achieved a higher speed and overtaken all others. Voyager 1 overtook Voyager 2 a few months after launch, on December 19, 1977. It overtook Pioneer 11 in 1981, and then Pioneer 10—becoming the probe farthest from the Sun—on February 17, 1998. Voyager 2 is moving faster than all other probes launched before it; it overtook Pioneer 11 in the late 1980s and then Pioneer 10 — becoming the second-farthest spacecraft from the Sun — in July 2023. Depending on how the "Pioneer anomaly" (heat radiating from the power source) affects it, New Horizons will also probably pass the Pioneer probes, but will need many years to do so. It will overtake Pioneer 11 in 2143, and will overtake Pioneer 10 in 2314, but will never overtake the Voyagers. == Speed and distance from the Sun ==

To put the distances in the table in context, Pluto's average distance (semi-major axis) is about 40 AU. Note: Data above as of December 2, 2025. Source: JPL, heavens-above.com, and for New Horizons. Solar escape velocity is a function of distance (r) from the Sun's center, given by :v_e = \sqrt{\frac{2GM_\text{sun}}{r}}, where the product G Msun is the heliocentric gravitational parameter. If r is measured in AU then the escape velocity in km/s becomes \frac{42.1}{\sqrt r}. The initial speed required to escape the Sun from its surface is 618 km/s ( or the speed of light), and drops down to at Earth's distance from the Sun (1 AU), and at a distance of 100 AU. File:Voyager speed and distance from Sun.svg|Voyager 1 and 2 speed and distance from the Sun File:Pioneer speed and distance from Sun.svg|Pioneer 10 and 11 speed and distance from the Sun File:New Horizons Speed and distance from Sun.svg|New Horizons speed and distance from the Sun. In order to leave the Solar System, the probe needs to reach the local escape velocity. Escape velocity from the sun without the influence of Earth is 42.1 km/s. In order to reach this speed, it is highly advantageous to use as a boost the orbital speed of the Earth around the Sun, which is 29.78 km/s. By later passing near a planet, a probe can gain extra speed from a gravity assist. ==Propulsion stages==

Every planetary probe was placed into its escape trajectory by a multistage rocket, the last stage of which ends up on nearly the same trajectory as the probe it launched. Because these stages cannot be actively guided, their trajectories are now different from the probes they launched (the probes having been guided with small thrusters that allowed course changes). 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: • Pioneer 10 third stage, a TE364-4 variant of the Star-37 solid fuel rocket. • Voyager 1 fourth stage, a Star 37E solid fuel rocket. • Voyager 2 fourth stage, a Star 37E solid fuel rocket. This was four months after New Horizons' Pluto flyby. 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. Once the spin rate was lowered, these masses and the wires were released, and so are also on an escape trajectory out of the Solar System. None of the above objects are trackable – they have no power or radio antennas, spin uncontrollably, and are too small to be detected. Their exact positions are unknowable beyond their projected Solar System escape trajectories. The third stage of Pioneer 11 is thought to be in solar orbit because its encounter with Jupiter would not have resulted in escape from the Solar System. New Horizons passed the Moon's orbit in just nine hours. The subsequent encounter with Jupiter only increased its velocity, and enabled the probe to arrive at Pluto three years earlier than without this encounter. 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. The New Horizons Centaur (second) stage is not escaping; it is in a 2.83-year heliocentric (solar) orbit. == Future ==

Given the huge emptiness of interstellar space, all the objects listed here are likely to continue into deep space in timelines that, barring the exceptionally unlikely chance of their colliding with (or being collected by) another object, could outlast even the main sequence existence of the Sun's life, billions of years hence. One estimated timescale as to the likelihood of the Pioneer or Voyager spacecraft colliding with a star (or stellar remnant) is 1020 (100 quintillion) years, or about 7 billion times the current age of the universe. They are very unlikely, however, to gain enough velocity to escape the Milky Way galaxy Ulysses is now switched off as its RTG power supply has run down, and so is uncontactable and cannot be tracked or guided in any way since 2009. Its exact trajectory is therefore unknowable as factors such as solar radiation pressure could significantly alter its encounter path. == Gallery ==

File:Voyager.jpg|Photograph of Voyager 1 / Voyager 2 File:Pioneer10-11.jpg|Artist's concept of Pioneer 10 / Pioneer 11 File:Pioneer 10 at Jupiter.gif|Artist's concept of Pioneer 10 near Jupiter File:15-011a-NewHorizons-PlutoFlyby-ArtistConcept-14July2015-20150115.jpg|Artist's concept of New Horizons approaching Pluto. File:PIA19703-PlutoFlyby-NewHorizons-ArtistConcept-20150709.jpg|Artist's concept of New Horizons near Pluto. ==See also==