paragraph_text: In orbital mechanics and aerospace engineering, a gravitational slingshot, gravity assist maneuver, or swing - by is the use of the relative movement (e.g. orbit around the Sun) and gravity of a planet or other astronomical object to alter the path and speed of a spacecraft, typically to save propellant and reduce expense. Gravity assistance can be used to accelerate a spacecraft, that is, to increase or decrease its speed or redirect its path. The ``assist ''is provided by the motion of the gravitating body as it pulls on the spacecraft. The gravity assist maneuver was first used in 1959 when the Soviet probe Luna 3 photographed the far side of Earth's Moon and it was used by interplanetary probes from Mariner 10 onwards, including the two Voyager probes' notable flybys of Jupiter and Saturn.

paragraph_text: Neptune is the eighth and farthest known planet from the Sun in the Solar System. In the Solar System, it is the fourth - largest planet by diameter, the third-most - massive planet, and the densest giant planet. Neptune is 17 times the mass of Earth and is slightly more massive than its near - twin Uranus, which is 15 times the mass of Earth and slightly larger than Neptune. Neptune orbits the Sun once every 164.8 years at an average distance of 30.1 AU (4.5 billion km). It is named after the Roman god of the sea and has the astronomical symbol ♆, a stylised version of the god Neptune's trident.

paragraph_text: The Galilean moons are the four largest moons of Jupiter -- Io, Europa, Ganymede, and Callisto. They were first seen by Galileo Galilei in January 1610, and recognized by him as satellites of Jupiter in March 1610. They are the first objects found to orbit another planet. Their names derive from the lovers of Zeus. They are among the largest objects in the Solar System with the exception of the Sun and the eight planets, with a radius larger than any of the dwarf planets. Ganymede is the largest moon in the Solar System, and is even bigger than the planet Mercury. The three inner moons -- Io, Europa, and Ganymede -- are in a 4: 2: 1 orbital resonance with each other. Because of their much smaller size, and therefore weaker self - gravitation, all of Jupiter's remaining moons have irregular forms rather than a spherical shape.

paragraph_text: 11 Ursae Minoris b is an extrasolar planet which orbits the K-type giant star 11 Ursae Minoris, located approximately 390 light years away in the constellation Ursa Minor. This planet has mass 10.5 MJ. However, since the mass is at lower limit and since inclination is not known, the actual mass is unknown. This planet may actually be a brown dwarf if a true mass is over 13 times that of Jupiter. This planet takes 17 months to orbit the star at the average distance of 1.54 AU in a circular orbit. This superjovian planet was detected by radial velocity method on August 12, 2009.

paragraph_text: As with the majority of extrasolar planet discoveries so far, it was found by detecting small variations in the radial velocity of the star it orbits, caused by the tug of its gravity. A study of the radial velocity of HD 217107 carried out in 1998 revealed that its motion along the line of sight varied over a 7.1 day cycle. The period and amplitude of this variation indicated that it was caused by a planetary companion in orbit around the star, with a minimum mass slightly greater than that of Jupiter. The planet's mean distance from the star is less than one fifth of Mercury's distance from the Sun.

paragraph_text: HD 215497 b is an extrasolar planet which orbits the K-type main sequence star HD 215497, located approximately 142 light years away in the constellation Tucana. This planet has at least 6.6 times the mass of Earth. This planet was detected by HARPS on October 19, 2009, together with 29 other planets, including HD 215497 c.

paragraph_text: HD 1461 b is an extrasolar planet, orbiting the 6th magnitude G-type star HD 1461, 76.5 light years away in the constellation Cetus. This planet has a minimum mass 6.4 times that of Earth and orbits at a distance of 0.0634 AU with an eccentricity of less than 0.131. It is currently unknown whether the planet is a gas giant like Uranus or Neptune, or has terrestrial composition like CoRoT-7 b. This planet was announced on 13 December 2009 after it was discovered using radial velocity measurements taken at the Keck and Anglo-Australian Observatories.

paragraph_text: HD 215497 c is an extrasolar planet which orbits the G-type main sequence star HD 215497, located approximately 142 light years away in the constellation Tucana. This planet has at least one-thirds the mass of Jupiter and takes 568 days to orbit the star at a semimajor axis of 1.282 AU. This planet was detected by HARPS on October 19, 2009, together with 29 other planets, including HD 215497 b.

paragraph_text: HD 43691 b is a massive jovian planet located approximately 280 light-years away in the constellation of Auriga. Because the inclination is unknown, only the minimum mass is known. The planet orbits close to the star, closer than Mercury to the Sun.

paragraph_text: HD 45350 b is an extrasolar planet located approximately 160 light-years away in the constellation of Auriga. It has a minimum mass about 1.79 times that of Jupiter. The mean distance of the planet from the star is more than the distance between Mars and the Sun, but the eccentricity of the orbit is nothing short of remarkable; at periastron the planet is as close to the star as Mercury is from the Sun, but at apastron it is 8 times further. No doubt seasons on the planet would be extreme.

paragraph_text: HAT-P-9b is an exoplanet approximately 1500 light years away in the constellation Auriga. This planet was found by the transit method on June 26, 2008. It has a mass 78% that of Jupiter and a radius 140% that of Jupiter. As with most transiting planets, this planet is a hot Jupiter, meaning this Jupiter-like planet orbits extremely close to its parent star, taking only 3.92 days to orbit.

paragraph_text: Hero Rupes is an escarpment on Mercury more than long located in the southern hemisphere of Mercury. Discovered by the "Mariner 10" spacecraft in 1974, it was formed by a thrust fault, thought to have occurred due to the shrinkage of the planet's core as it cooled over time.

paragraph_text: HD 11964 c is an extrasolar planet approximately 110 light-years away in the constellation of Cetus. The planet was discovered in a close-orbit around the yellow subgiant star HD 11964. The planet has a minimum mass 35 times the mass of Earth and is located in a mildly eccentric orbit which takes almost 38 days to complete. HD 11964 c was a possible planet discovered on the same day as HD 11964 b in 2005. HD 11964 c was first proposed in a paper published in 2007, and finally confirmed with new data presented in a review of multi-planet systems which appeared on the arXiv preprint website in 2008.

paragraph_text: HD 7199 is a K-class star located in the constellation Tucana. The High Accuracy Radial Velocity Planet Searcher (HARPS) in Chile found it to have a planet either 0.290 the mass of Jupiter or 92 times the mass of Earth with an orbital period of 615 days.

paragraph_text: Neptune is the eighth and farthest known planet from the Sun in the Solar System. It is the fourth-largest planet by diameter and the third-largest by mass. Among the giant planets in the Solar System, Neptune is the most dense. Neptune is 17 times the mass of Earth and is slightly more massive than its near-twin Uranus, which is 15 times the mass of Earth and slightly larger than Neptune.[c] Neptune orbits the Sun once every 164.8 years at an average distance of 30.1 astronomical units (4.50×109 km). Named after the Roman god of the sea, its astronomical symbol is ♆, a stylised version of the god Neptune's trident.

paragraph_text: It was only the orbit of the planet Mercury that Newton's Law of Gravitation seemed not to fully explain. Some astrophysicists predicted the existence of another planet (Vulcan) that would explain the discrepancies; however, despite some early indications, no such planet could be found. When Albert Einstein formulated his theory of general relativity (GR) he turned his attention to the problem of Mercury's orbit and found that his theory added a correction, which could account for the discrepancy. This was the first time that Newton's Theory of Gravity had been shown to be less correct than an alternative.

paragraph_text: The planet Neptune was mathematically predicted before it was directly observed. With a prediction by Urbain Le Verrier, telescopic observations confirming the existence of a major planet were made on the night of September 23 -- 24, 1846, at the Berlin Observatory, by astronomer Johann Gottfried Galle (assisted by Heinrich Louis d'Arrest), working from Le Verrier's calculations. It was a sensational moment of 19th century science and dramatic confirmation of Newtonian gravitational theory. In François Arago's apt phrase, Le Verrier had discovered a planet ``with the point of his pen ''.

paragraph_text: Neptune is not visible to the unaided eye and is the only planet in the Solar System found by mathematical prediction rather than by empirical observation. Unexpected changes in the orbit of Uranus led Alexis Bouvard to deduce that its orbit was subject to gravitational perturbation by an unknown planet. Neptune was subsequently observed with a telescope on 23 September 1846 by Johann Galle within a degree of the position predicted by Urbain Le Verrier. Its largest moon, Triton, was discovered shortly thereafter, though none of the planet's remaining known 14 moons were located telescopically until the 20th century. The planet's distance from Earth gives it a very small apparent size, making it challenging to study with Earth-based telescopes. Neptune was visited by Voyager 2, when it flew by the planet on 25 August 1989. The advent of Hubble Space Telescope and large ground-based telescopes with adaptive optics has recently allowed for additional detailed observations from afar.

paragraph_text: Since 1973 a number of automated spacecraft have visited Jupiter, most notably the Pioneer 10 space probe, the first spacecraft to get close enough to Jupiter to send back revelations about the properties and phenomena of the Solar System's largest planet. Flights to other planets within the Solar System are accomplished at a cost in energy, which is described by the net change in velocity of the spacecraft, or delta-v. Entering a Hohmann transfer orbit from Earth to Jupiter from low Earth orbit requires a delta-v of 6.3 km/s which is comparable to the 9.7 km/s delta-v needed to reach low Earth orbit. Gravity assists through planetary flybys can be used to reduce the energy required to reach Jupiter, albeit at the cost of a significantly longer flight duration.

paragraph_text: Neptune is the eighth and farthest known planet from the Sun in the Solar System. In the Solar System, it is the fourth - largest planet by diameter, the third-most - massive planet, and the densest giant planet. Neptune is 17 times the mass of Earth and is slightly more massive than its near - twin Uranus, which is 15 times the mass of Earth and slightly larger than Neptune. Neptune orbits the Sun once every 164.8 years at an average distance of 30.1 astronomical units (4.50 × 10 km). It is named after the Roman god of the sea and has the astronomical symbol ♆, a stylised version of the god Neptune's trident.

Question: What spacecraft used the gravitational pull of the planet the minimum mass was a little bit bigger than?
Answer: Voyager probes