Voyager 2 - Wikipedia Voyager 2 Space probe and the second - farthest man - made object from Earth Voyager 2 Model of the Voyager spacecraft design Mission type Planetary exploration Operator NASA / JPL COSPAR ID 1977 - 076A SATCAT no. 10271 Website voyager.jpl.nasa.gov Mission duration 40 years, 10 months and 23 days elapsed Planetary mission : 12 years, 1 month, 12 days Interstellar mission : 28 years, 9 months and 11 days elapsed ( continuing ) Spacecraft properties Manufacturer Jet Propulsion Laboratory Launch mass 825.5 kilograms ( 1,820 lb ) Power 420 watts Start of mission Launch date August 20, 1977, 14 : 29 : 00 ( 1977 - 08 - 20UTC14 : 29Z ) UTC Rocket Titan IIIE Launch site Cape Canaveral LC - 41 Flyby of Jupiter Closest approach July 9, 1979, 22 : 29 : 00 UTC Distance 570,000 kilometers ( 350,000 mi ) Flyby of Saturn Closest approach August 25, 1981, 03 : 24 : 05 UTC Distance 101,000 km ( 63,000 mi ) Flyby of Uranus Closest approach January 24, 1986, 17 : 59 : 47 UTC Distance 81,500 km ( 50,600 mi ) Flyby of Neptune Closest approach August 25, 1989, 03 : 56 : 36 UTC Distance 4,951 km ( 3,076 mi ) Flagship ← Viking 2 Voyager 1 → Voyager 2 is a space probe launched by NASA on August 20, 1977, to study the outer planets. Part of the Voyager program, it was launched 16 days before its twin, Voyager 1, on a trajectory that took longer to reach Jupiter and Saturn but enabled further encounters with Uranus and Neptune. It is the only spacecraft to have visited either of the ice giants. Its primary mission ended with the exploration of the Neptunian system on October 2, 1989, after having visited the Uranian system in 1986, the Saturnian system in 1981, and the Jovian system in 1979. Voyager 2 is now in its extended mission to study the outer reaches of the Solar System and has been operating for 40 years, 10 months and 23 days as of July 13, 2018. It remains in contact through the Deep Space Network. At a distance of 118 AU ( 1.77 × 10 km ) from the Sun as of July 10, 2018, Voyager 2 is the fourth of five spacecraft to achieve the escape velocity that will allow them to leave the Solar System. The probe was moving at a velocity of 15.3741 km / s ( 55,347 km / h ) relative to the Sun as of July 2018 and is traveling through the heliosheath. Upon reaching interstellar space, Voyager 2 is expected to provide the first direct measurements of the density and temperature of the interstellar plasma. Contents 1 History 1.1 Background 1.2 Spacecraft design 1.2. 1 Communications 1.2. 2 Power 1.2. 3 Scientific instruments 2 Mission profile 3 Launch and trajectory 3.1 Encounter with Jupiter 3.2 Encounter with Saturn 3.3 Encounter with Uranus 3.4 Encounter with Neptune 4 Interstellar mission 5 Future of the probe 6 Golden record 7 See also 8 References 9 Further reading 10 External links History Background In the early space age, it was realized that a coincidental alignment of the outer planets would occur in the late 1970s and enable a single probe to visit Jupiter, Saturn, Uranus, and Neptune by taking advantage of the then - new technique of gravity assists. NASA began work on a Grand Tour, which evolved into a massive project involving two groups of two probes each, with one group visiting Jupiter, Saturn, and Pluto and the other Jupiter, Uranus, and Neptune. The spacecraft would be designed with redundant systems to ensure survival through the entire tour. By 1972 the mission was scaled back and replaced with two Mariner - derived spacecraft, the Mariner Jupiter - Saturn probes. To keep apparent lifetime program costs low, the mission would include only flybys of Jupiter and Saturn, but keep the Grand Tour option open. As the program progressed, the name was changed to Voyager. The primary mission of Voyager 1 was to explore Jupiter, Saturn, and Saturn 's moon, Titan. Voyager 2 was also to explore Jupiter and Saturn, but on a trajectory that would have option of continuing on to Uranus and Neptune, or being redirected to Titan as a backup for Voyager 1. Upon successful completion of Voyager 1 's objectives, Voyager 2 would get a mission extension to send the probe on towards Uranus and Neptune. Spacecraft design Constructed by the Jet Propulsion Laboratory ( JPL ), Voyager 2 included 16 hydrazine thrusters, three - axis stabilization, gyroscopes and celestial referencing instruments ( Sun sensor / Canopus Star Tracker ) to maintain pointing of the high - gain antenna toward Earth. Collectively these instruments are part of the Attitude and Articulation Control Subsystem ( AACS ) along with redundant units of most instruments and 8 backup thrusters. The spacecraft also included 11 scientific instruments to study celestial objects as it traveled through space. Communications Built with the intent for eventual interstellar travel, Voyager 2 included a large, 3.7 m ( 12 ft ) parabolic, high - gain antenna ( see diagram ) to transceive data via the Deep Space Network on the Earth. Communications are conducted over the S - band ( about 13 cm wavelength ) and X-band ( about 3.6 cm wavelength ) providing data rates as high as 115.2 kilobits per second at the distance of Jupiter, and then ever - decreasing as the distance increased, because of the inverse - square law. When the spacecraft is unable to communicate with Earth, the Digital Tape Recorder ( DTR ) can record about 64 kilobytes of data for transmission at another time. Power The spacecraft was equipped with 3 Multihundred - Watt radioisotope thermoelectric generators ( MHW RTG ). Each RTG includes 24 pressed plutonium oxide spheres, and provided enough heat to generate approximately 157 W of electrical power at launch. Collectively, the RTGs supplied the spacecraft with 470 watts at launch, and will allow operations to continue until at least 2020. RTG Inner Heat Source RTG Assembly RTG unit Scientific instruments Main article : Voyager program Instrument Name Abr. Description Imaging Science System ( disabled ) ( ISS ) Utilizes a two - camera system ( narrow - angle / wide - angle ) to provide imagery of Jupiter, Saturn and other objects along the trajectory. More hide Filters Narrow Angle Camera Filters Name Wavelength Spectrum Sensitivity Clear 280 nm -- 640 nm UV 280 nm -- 370 nm Violet 350 nm -- 450 nm Blue 430 nm -- 530 nm ' ' ' Green 530 nm -- 640 nm ' ' ' Orange 590 nm -- 640 nm ' ' ' Wide Angle Camera Filters Name Wavelength Spectrum Sensitivity Clear 280 nm -- 640 nm ' ' ' Violet 350 nm -- 450 nm Blue 430 nm -- 530 nm CH - U 536 nm -- 546 nm Green 530 nm -- 640 nm Na - D 588 nm -- 590 nm Orange 590 nm -- 640 nm CH - JST 614 nm -- 624 nm Principal investigator : Bradford Smith / University of Arizona ( PDS / PRN website ) Data : PDS / PDI data catalog, PDS / PRN data catalog Radio Science System ( disabled ) ( RSS ) Utilized the telecommunications system of the Voyager spacecraft to determine the physical properties of planets and satellites ( ionospheres, atmospheres, masses, gravity fields, densities ) and the amount and size distribution of material in Saturn 's rings and the ring dimensions. More Principal investigator : G. Tyler / Stanford University PDS / PRN overview Data : PDS / PPI data catalog, PDS / PRN data catalog ( VG_2803 ), NSSDC Saturn data archive Infrared Interferometer Spectrometer ( disabled ) ( IRIS ) Investigates both global and local energy balance and atmospheric composition. Vertical temperature profiles are also obtained from the planets and satellites as well as the composition, thermal properties, and size of particles in Saturn 's rings. More Principal investigator : Rudolf Hanel / NASA Goddard Space Flight Center ( PDS / PRN website ) Data : PDS / PRN data catalog, PDS / PRN expanded data catalog ( VGIRIS_0001, VGIRIS_002 ) Ultraviolet Spectrometer ( disabled ) ( UVS ) Designed to measure atmospheric properties, and to measure radiation. More Principal investigator : A. Broadfoot / University of Southern California ( PDS / PRN website ) Data : PDS / PRN data catalog Triaxial Fluxgate Magnetometer ( active ) ( MAG ) Designed to investigate the magnetic fields of Jupiter and Saturn, the solar - wind interaction with the magnetospheres of these planets, and the interplanetary magnetic field out to the solar wind boundary with the interstellar magnetic field and beyond, if crossed. More Principal investigator : Norman Ness / NASA Goddard Space Flight Center ( website ) Data : PDS / PPI data catalog, NSSDC data archive Plasma Spectrometer ( active ) ( PLS ) Investigates the macroscopic properties of the plasma ions and measures electrons in the energy range from 5 eV to 1 keV. More Principal investigator : John Richardson / MIT ( website ) Data : PDS / PPI data catalog, NSSDC data archive Low Energy Charged Particle Instrument ( active ) ( LECP ) Measures the differential in energy fluxes and angular distributions of ions, electrons and the differential in energy ion composition. More Principal investigator : Stamatios Krimigis / JHU / APL / University of Maryland ( JHU / APL website / UMD website / KU website ) Data : UMD data plotting, PDS / PPI data catalog, NSSDC data archive Cosmic Ray System ( active ) ( CRS ) Determines the origin and acceleration process, life history, and dynamic contribution of interstellar cosmic rays, the nucleosynthesis of elements in cosmic - ray sources, the behavior of cosmic rays in the interplanetary medium, and the trapped planetary energetic - particle environment. More Principal investigator : Edward Stone / Caltech / NASA Goddard Space Flight Center ( website ) Data : NSSDC data archive Planetary Radio Astronomy Investigation ( disabled ) ( PRA ) Utilizes a sweep - frequency radio receiver to study the radio - emission signals from Jupiter and Saturn. More Voyager : Sounds Of The Cosmos, the Album made from Voyager 's PRA Instrument Recordings Principal investigator : James Warwick / University of Colorado Data : PDS / PPI data catalog Photopolarimeter System ( disabled ) ( PPS ) Utilized a telescope with a polarizer to gather information on surface texture and composition of Jupiter and Saturn and information on atmospheric scattering properties and density for both planets. More Principal investigator : Arthur Lane / JPL ( PDS / PRN website ) Data : PDS / PRN data catalog Plasma Wave System ( partially disabled ) ( PWS ) Provides continuous, sheath - independent measurements of the electron - density profiles at Jupiter and Saturn as well as basic information on local wave - particle interaction, useful in studying the magnetospheres. More Principal investigator : Donald Gurnett / University of Iowa ( website ) Data : PDS / PPI data catalog For more details on the Voyager space probes ' identical instrument packages, see the separate article on the overall Voyager Program. Images of the spacecraft Voyager spacecraft diagram. Voyager in transport to a solar thermal test chamber. Voyager 2 awaiting payload entry into a Titan IIIE / Centaur rocket. Media related to the Voyager spacecraft at Wikimedia Commons Mission profile Voyager 2 's trajectory from the earth, following the ecliptic through 1989 at Neptune and now heading south into the constellation Pavo Timeline of travel Date Event 1977 - 08 - 20 Spacecraft launched at 14 : 29 : 00 UTC. 1977 - 12 - 10 Entered asteroid belt. 1977 - 12 - 19 Voyager 1 overtakes Voyager 2. ( see diagram ) 1978 - 06 Primary radio receiver fails. Remainder of mission flown using backup. 1978 - 10 - 21 Exited asteroid belt 1979 - 04 - 25 Start Jupiter observation phase show Time Event 1979 - 07 - 08 Encounter with Jovian system. 0012 : 21 Callisto flyby at 214,930 km. 1979 - 07 - 09 0007 : 14 Ganymede flyby at 62,130 km. 0017 : 53 Europa flyby at 205,720 km. 0020 : 01 Amalthea flyby at 558,370 km. 0022 : 29 Jupiter closest approach at 721,670 km from the center of mass. 0023 : 17 Io flyby at 1,129,900 km. 1979 - 08 - 05 Phase Stop 1981 - 06 - 05 Start Saturn observation phase. show Time Event 1981 - 08 - 22 Encounter with Saturnian system. 0001 : 26 : 57 Iapetus flyby at 908,680 km. 1981 - 08 - 25 0001 : 25 : 26 Hyperion flyby at 431,370 km. 0009 : 37 : 46 Titan flyby at 666,190 km. 0022 : 57 : 33 Helene flyby at 314,090 km. 1981 - 08 - 26 0001 : 04 : 32 Dione flyby at 502,310 km. 0002 : 22 : 17 Calypso flyby at 151,590 km. 0002 : 24 : 26 Mimas flyby at 309,930 km. 0003 : 19 : 18 Pandora flyby at 107,000 km. 0003 : 24 : 05 Saturn closest approach at 161,000 km from the center of mass. 0003 : 33 : 02 Atlas 287,000 km. 0003 : 45 : 16 Enceladus flyby at 87,010 km. 0003 : 50 : 04 Janus at 223,000 km. 0004 : 05 : 56 Epimetheus at 147,000 km. 0006 : 02 : 47 Telesto at 270,000 km. 0006 : 12 : 30 Tethys flyby at 93,010 km. 0006 : 28 : 48 Rhea flyby at 645,260 km. 1981 - 09 - 04 0001 : 22 : 34 Phoebe flyby at 2,075,640 km. 1981 - 09 - 25 Phase Stop 1985 - 11 - 04 Start Uranus observation phase. show Time Event 1986 - 01 - 24 Encounter with Uranian system. 0016 : 50 Miranda flyby at 29,000 km. 0017 : 25 Ariel flyby at 127,000 km. 0017 : 25 Umbriel flyby at 325,000 km. 0017 : 25 Titania flyby at 365,200 km. 0017 : 25 Oberon flyby at 470,600 km. 0017 : 59 : 47 Uranus closest approach at 107,000 km from the center of mass. 1986 - 02 - 25 Phase Stop 1987 - 08 - 20 10 years of continuous flight and operation at 14 : 29 : 00 UTC. 1989 - 06 - 05 Start Neptune observation phase. show Time Event 1989 - 08 - 25 Encounter with Neptunian system. 0003 : 56 : 36 Neptune closest approach at 4,950 km. 0004 : 51 Larissa flyby at 60,180 km. 0005 : 29 Proteus flyby at 97,860 km. 0009 : 23 Triton flyby at 39,800 km. 1989 - 10 - 02 Phase Stop 1989 - 10 - 02 Begin Voyager Interstellar Mission. Interstellar phase 1997 - 08 - 20 20 years of continuous flight and operation at 14 : 29 : 00 UTC. 1998 - 11 - 13 Terminate scan platform and UV observations. 2007 - 08 - 20 30 years of continuous flight and operation at 14 : 29 : 00 UTC. 2007 - 09 - 06 Terminate data tape recorder operations. 2008 - 02 - 22 Terminate planetary radio astronomy experiment operations. 2011 - 11 - 07 Switch to backup thrusters to conserve power 2017 - 08 - 20 40 years of continuous flight and operation at 14 : 29 : 00 UTC. Launch and trajectory The Voyager 2 probe was launched on August 20, 1977, by NASA from Space Launch Complex 41 at Cape Canaveral, Florida, aboard a Titan IIIE / Centaur launch vehicle. Two weeks later, the twin Voyager 1 probe would be launched on September 5, 1977. However, Voyager 1 would reach both Jupiter and Saturn sooner, as Voyager 2 had been launched into a longer, more circular trajectory. Voyager 2 launch on August 20, 1977 with a Titan IIIE / Centaur. Animation of Voyager 2 's trajectory from 20 August 1977 to 31 December 2018 Voyager 2 Earth Jupiter Saturn Uranus Neptune Sun Trajectory of Voyager 2 primary mission. Plot of Voyager 2 's heliocentric velocity against its distance from the Sun, illustrating the use of gravity assists to accelerate the spacecraft by Jupiter, Saturn and Uranus. To observe Triton, Voyager 2 passed over Neptune 's north pole, resulting in an acceleration out of the plane of the ecliptic, and, as a result, a reduced velocity relative to the Sun. In April 1978, a complication arose when no commands were transmitted to Voyager 2 for a period of time, causing the spacecraft to switch from its primary radio receiver to its backup receiver. Sometime afterwards, the primary receiver failed altogether. The backup receiver was functional, but a failed capacitor in the receiver meant that it could only receive transmissions that were sent at a precise frequency, and this frequency would be affected by the Earth 's rotation ( due to the Doppler effect ) and the onboard receiver 's temperature, among other things. For each subsequent transmission to Voyager 2, it was necessary for engineers to calculate the specific frequency for the signal so that it could be received by the spacecraft. Encounter with Jupiter Main article : Exploration of Jupiter The trajectory of Voyager 2 through the Jupiter system Voyager 2 's closest approach to Jupiter occurred on July 9, 1979. It came within 570,000 km ( 350,000 mi ) of the planet 's cloud tops. It discovered a few rings around Jupiter, as well as volcanic activity on the moon Io. The Great Red Spot was revealed as a complex storm moving in a counterclockwise direction. An array of other smaller storms and eddies were found throughout the banded clouds. Discovery of active volcanism on Io was easily the greatest unexpected discovery at Jupiter. It was the first time active volcanoes had been seen on another body in the Solar System. Together, the Voyagers observed the eruption of nine volcanoes on Io, and there is evidence that other eruptions occurred between the two Voyager fly - bys. The moon Europa displayed a large number of intersecting linear features in the low - resolution photos from Voyager 1. At first, scientists believed the features might be deep cracks, caused by crustal rifting or tectonic processes. The closer high - resolution photos from Voyager 2, however, left scientists puzzled : The features were so lacking in topographic relief that as one scientist described them, they `` might have been painted on with a felt marker. '' Europa is internally active due to tidal heating at a level about one - tenth that of Io. Europa is thought to have a thin crust ( less than 30 km ( 19 mi ) thick ) of water ice, possibly floating on a 50 - kilometer - deep ( 30 mile ) ocean. Two new, small satellites, Adrastea and Metis, were found orbiting just outside the ring. A third new satellite, Thebe, was discovered between the orbits of Amalthea and Io. The Great Red Spot photographed during the Voyager 2 flyby of Jupiter. A transit of Io across Jupiter, July 9, 1979. Eruption of a volcano on Io, photographed by Voyager 2. A color mosaic of Europa. A color mosaic of Ganymede. Callisto photographed at a distance of 1 million kilometers. One faint ring of Jupiter photographed during the flyby. Atmospheric eruptive event on Jupiter. Media related to the Voyager 2 Jupiter encounter at Wikimedia Commons Encounter with Saturn Main article : Exploration of Saturn The closest approach to Saturn occurred on August 26, 1981. While passing behind Saturn ( as viewed from Earth ), Voyager 2 probed Saturn 's upper atmosphere with its radio link to gather information on atmospheric temperature and density profiles. Voyager 2 found that at the uppermost pressure levels ( seven kilopascals of pressure ), Saturn 's temperature was 70 kelvins ( − 203 ° C ), while at the deepest levels measured ( 120 kilopascals ) the temperature increased to 143 K ( − 130 ° C ). The north pole was found to be 10 kelvins cooler, although this may be seasonal ( see also Saturn Oppositions ). After the fly - by of Saturn, the camera platform of Voyager 2 locked up briefly, putting plans to officially extend the mission to Uranus and Neptune in jeopardy. The mission 's engineers were able to fix the problem ( caused by an overuse that temporarily depleted its lubricant ), and the Voyager 2 probe was given the go - ahead to explore the Uranian system. Voyager 2 Saturn approach view. North, polar region of Saturn imaged in orange and UV filters. Color image of Enceladus showing terrain of widely varying ages. Cratered surface of Tethys at 594,000 km. Atmosphere of Titan imaged from 2.3 million km. Titan occultation of the Sun from 0.9 million km. Two - toned Iapetus, August 22, 1981. `` Spoke '' features observed in the rings of Saturn. Media related to the Voyager 2 Saturn encounter at Wikimedia Commons Encounter with Uranus This section does not cite any sources. Please help improve this section by adding citations to reliable sources. Unsourced material may be challenged and removed. ( August 2011 ) Main article : Exploration of Uranus The closest approach to Uranus occurred on January 24, 1986, when Voyager 2 came within 81,500 kilometers ( 50,600 mi ) of the planet 's cloud tops. Voyager 2 also discovered the moons Cordelia, Ophelia, Bianca, Cressida, Desdemona, Juliet, Portia, Rosalind, Belinda, Perdita and Puck ; studied the planet 's unique atmosphere, caused by its axial tilt of 97.8 ° ; and examined the Uranian ring system. Uranus is the third largest ( Neptune has a larger mass, but a smaller volume ) planet in the Solar System. It orbits the Sun at a distance of about 2.8 billion kilometers ( 1.7 billion miles ), and it completes one orbit every 84 Earth years. The length of a day on Uranus as measured by Voyager 2 is 17 hours, 14 minutes. Uranus is unique among the planets in that its axial tilt is about 90 °, meaning that its axis is roughly parallel with, not perpendicular to, the plane of the ecliptic. This extremely large tilt of its axis is thought to be the result of a collision between the accumulating planet Uranus with another planet - sized body early in the history of the Solar System. Given the unusual orientation of its axis, with the polar regions of Uranus exposed for periods of many years to either continuous sunlight or darkness, planetary scientists were not at all sure what to expect when observing Uranus. Voyager 2 found that one of the most striking effects of the sideways orientation of Uranus is the effect on the tail of the planetary magnetic field. This is itself tilted about 60 ° from the Uranian axis of rotation. The planet 's magneto tail was shown to be twisted by the rotation of Uranus into a long corkscrew shape following the planet. The presence of a significant magnetic field for Uranus was not at all known until Voyager 2 's arrival. The radiation belts of Uranus were found to be of an intensity similar to those of Saturn. The intensity of radiation within the Uranian belts is such that irradiation would `` quickly '' darken -- within 100,000 years -- any methane that is trapped in the icy surfaces of the inner moons and ring particles. This kind of darkening might have contributed to the darkened surfaces of the moons and the ring particles, which are almost uniformly dark gray in color. A high layer of haze was detected around the sunlit pole of Uranus. This area was also found to radiate large amounts of ultraviolet light, a phenomenon that is called `` dayglow. '' The average atmospheric temperature is about 60 K ( − 350 ° F / − 213 ° C ). Surprisingly, the illuminated and dark poles, and most of the planet, exhibit nearly the same temperatures at the cloud tops. The Uranian moon Miranda, the innermost of the five large moons, was discovered to be one of the strangest bodies yet seen in the Solar System. Detailed images from Voyager 2 's flyby of Miranda showed huge canyons made from geological faults as deep as 20 kilometers ( 12 mi ), terraced layers, and a mixture of old and young surfaces. One hypothesis suggests that Miranda might consist of a reaggregation of material following an earlier event when Miranda was shattered into pieces by a violent impact. All nine of the previously known Uranian rings were studied by the instruments of Voyager 2. These measurements showed that the Uranian rings are distinctly different from those at Jupiter and Saturn. The Uranian ring system might be relatively young, and it did not form at the same time that Uranus did. The particles that make up the rings might be the remnants of a moon that was broken up by either a high - velocity impact or torn up by tidal effects. Uranus as viewed by Voyager 2 Departing image of crescent Uranus. Fractured surface of Miranda. Ariel as imaged from 130,000 km. Color composite of Titania from 500,000 km. Umbriel ( moon ) imaged from 550,000 km. Oberon ( computer generated image ). The Rings of Uranus imaged by Voyager 2. Media related to the Voyager 2 Uranus encounter at Wikimedia Commons Encounter with Neptune Main article : Exploration of Neptune Following a mid-course correction in 1987, Voyager 2 's closest approach to Neptune occurred on August 25, 1989. Because this was the last planet of the Solar System that Voyager 2 could visit, the Chief Project Scientist, his staff members, and the flight controllers decided to also perform a close fly - by of Triton, the larger of Neptune 's two originally known moons, so as to gather as much information on Neptune and Triton as possible, regardless of Voyager 2 's departure angle from the planet. This was just like the case of Voyager 1 's encounters with Saturn and its massive moon Titan. Through repeated computerized test simulations of trajectories through the Neptunian system conducted in advance, flight controllers determined the best way to route Voyager 2 through the Neptune - Triton system. Since the plane of the orbit of Triton is tilted significantly with respect to the plane of the ecliptic, through mid-course corrections, Voyager 2 was directed into a path about three thousand miles above the north pole of Neptune. At that time, Triton was behind and below ( south of ) Neptune ( at an angle of about 25 degrees below the ecliptic ), close to the apoapsis of its elliptical orbit. The gravitational pull of Neptune bent the trajectory of Voyager 2 down in the direction of Triton. In less than 24 hours, Voyager 2 traversed the distance between Neptune and Triton, and then observed Triton 's northern hemisphere as it passed over its north pole. The net and final effect on Voyager 2 was to bend its trajectory south below the plane of the ecliptic by about 30 degrees. Voyager 2 is on this path permanently, and hence, it is exploring space south of the plane of the ecliptic, measuring magnetic fields, charged particles, etc., there, and sending the measurements back to the Earth via telemetry. While in the neighborhood of Neptune, Voyager 2 discovered the `` Great Dark Spot '', which has since disappeared, according to observations by the Hubble Space Telescope. Originally thought to be a large cloud itself, the `` Great Dark Spot '' was later hypothesized to be a hole in the visible cloud deck of Neptune. With the decision of the International Astronomical Union to reclassify Pluto as a `` dwarf planet '' in 2006, the flyby of Neptune by Voyager 2 in 1989 became the point when every known planet in the Solar System had been visited at least once by a space probe. Voyager 2 image of Neptune. Neptune and Triton three days after Voyager 2 flyby. Despina as imaged from Voyager 2. Cratered surface of Larissa. Dark surface of Proteus. Color mosaic of Voyager 2 Triton. Cirrus clouds imaged above gaseous Neptune. Rings of Neptune taken in occultation from 280,000 km. Media related to the Voyager 2 Neptune encounter at Wikimedia Commons Interstellar mission Once its planetary mission was over, Voyager 2 was described as working on an interstellar mission, which NASA is using to find out what the Solar System is like beyond the heliosphere. Voyager 2 is currently transmitting scientific data at about 160 bits per second. Information about continuing telemetry exchanges with Voyager 2 is available from Voyager Weekly Reports. Map showing location and trajectories of the Pioneer 10, Pioneer 11, Voyager 1, and Voyager 2 spacecraft, as of April 4, 2007. On November 29, 2006, a telemetered command to Voyager 2 was incorrectly decoded by its on - board computer -- in a random error -- as a command to turn on the electrical heaters of the spacecraft 's magnetometer. These heaters remained turned on until December 4, 2006, and during that time, there was a resulting high temperature above 130 ° C ( 266 ° F ), significantly higher than the magnetometers were designed to endure, and a sensor rotated away from the correct orientation. As of this date it had not been possible to fully diagnose and correct for the damage caused to Voyager 2 's magnetometer, although efforts to do so were proceeding. On August 30, 2007, Voyager 2 passed the termination shock and then entered into the heliosheath, approximately 1 billion miles ( 1.6 billion km ) closer to the Sun than Voyager 1 did. This is due to the interstellar magnetic field of deep space. The southern hemisphere of the Solar System 's heliosphere is being pushed in. On April 22, 2010, Voyager 2 encountered scientific data format problems. On May 17, 2010, JPL engineers revealed that a flipped bit in an on - board computer had caused the issue, and scheduled a bit reset for May 19. On May 23, 2010, Voyager 2 resumed sending science data from deep space after engineers fixed the flipped bit. Currently research is being made into marking the area of memory with the flipped bit off limits or disallowing its use. The Low - Energy Charged Particle Instrument is currently operational, and data from this instrument concerning charged particles is being transmitted to Earth. This data permits measurements of the heliosheath and termination shock. There has also been a modification to the on - board flight software to delay turning off the AP Branch 2 backup heater for one year. It was scheduled to go off February 2, 2011 ( DOY 033, 2011 -- 033 ). Simulated view of the position of Voyager 2 as of February 8, 2012 showing spacecraft trajectory since launch On July 25, 2012, Voyager 2 was traveling at 15.447 km / s relative to the Sun at about 99.13 astronomical units ( 1.4830 × 10 km ) from the Sun, at − 55.29 ° declination and 19.888 h right ascension, and also at an ecliptic latitude of − 34.0 degrees, placing it in the constellation Telescopium as observed from Earth. This location places it deep in the scattered disc, and traveling outward at roughly 3.264 AU per year. It is more than twice as far from the Sun as Pluto, and far beyond the perihelion of 90377 Sedna, but not yet beyond the outer limits of the orbit of the dwarf planet Eris. On September 9, 2012, Voyager 2 was 99.077 AU ( 1.48217 × 10 km ; 9.2098 × 10 mi ) from the Earth and 99.504 AU ( 1.48856 × 10 km ; 9.2495 × 10 mi ) from the Sun ; and traveling at 15.436 km / s ( 34,530 mph ) ( relative to the Sun ) and traveling outward at about 3.256 AU per year. Sunlight takes 13.73 hours to get to Voyager 2. The brightness of the Sun from the spacecraft is magnitude - 16.7. Voyager 2 is heading in the direction of the constellation Telescopium. ( To compare, Proxima Centauri, the closest star to the Sun, is about 4.2 light - years ( or 7016396434357355000 ♠ 2.65 × 10 AU ) distant. Voyager 2 's current relative velocity to the Sun is 15.436 km / s ( 55,570 km / h ; 34,530 mph ). This calculates as 3.254 AU per year, about 10 % slower than Voyager 1. At this velocity, 81,438 years would pass before Voyager 2 reaches the nearest star, Proxima Centauri, were the spacecraft traveling in the direction of that star. ( Voyager 2 will need about 19,390 years at its current velocity to travel a complete light year ) On November 7, 2012, Voyager 2 reached 100 AU from the sun, making it the third human - made object to reach 100 AU. Voyager 1 was 122 AU from the Sun, and Pioneer 10 is presumed to be at 107 AU. While Pioneer has ceased communications, both the Voyager spacecraft are performing well and are still communicating. The current position of Voyagers as of early 2013. Note the vast distances condensed into an exponential scale : Earth is 1 astronomical unit ( AU ) from the Sun ; Saturn is at 9 AU, and the heliopause is at more than 100 AU. Neptune is 30.1 AU from the Sun ; thus the edge of interstellar space is more than three times as far from the Sun as the last planet. In 2013 Voyager 1 was escaping the solar system at a speed of about 3.6 AU per year, while Voyager 2 was only escaping at 3.3 AU per year. ( Each year Voyager 1 increases its lead over Voyager 2 ) By July 10, 2018, Voyager 2 was at a distance of 118 AU ( 1.77 × 10 km ) from the Sun. There is a variation in distance from Earth caused by the Earth 's revolution around the Sun relative to Voyager 2. Future of the probe It was originally thought that Voyager 2 would enter interstellar space in early 2016, with its plasma spectrometer providing the first direct measurements of the density and temperature of the interstellar plasma. However, the spacecraft may instead reach interstellar space sometime in either late 2019 or early 2020, when it will reach a similar distance from the Sun as Voyager 1 did when it crossed into interstellar space back in 2012. Voyager 2 is not headed toward any particular star, although in roughly 40,000 years it should pass 1.7 light - years from the star Ross 248. And if undisturbed for 296,000 years, Voyager 2 should pass by the star Sirius at a distance of 4.3 light - years. Voyager 2 is expected to keep transmitting weak radio messages until at least 2025, over 48 years after it was launched. Year End of specific capabilities as a result of the available electrical power limitations 1998 Termination of scan platform and UVS observations 2007 Termination of Digital Tape Recorder ( DTR ) operations ( It was no longer needed due to a failure on the High Waveform Receiver on the Plasma Wave Subsystem ( PWS ) on June 30, 2002. ) 2008 Power off Planetary Radio Astronomy Experiment ( PRA ) 2016 approx Termination of gyroscopic operations 2020 approx Initiate instrument power sharing 2025 or slightly afterwards Can no longer power any single instrument Golden record A child 's greeting in English recorded on the Voyager Golden Record Voyager Golden Record Main article : Voyager Golden Record Each Voyager space probe carries a gold - plated audio - visual disc in the event that either spacecraft is ever found by intelligent life - forms from other planetary systems. The discs carry photos of the Earth and its lifeforms, a range of scientific information, spoken greetings from the people ( e.g. the Secretary - General of the United Nations and the President of the United States, and the children of the Planet Earth ) and a medley, `` Sounds of Earth '', that includes the sounds of whales, a baby crying, waves breaking on a shore, and a collection of music, including works by Mozart, Blind Willie Johnson, Chuck Berry 's `` Johnny B. Goode '', Valya Balkanska and other Eastern and Western classics and ethnic performers. ( see also Music in space ) See also Spaceflight portal Solar System portal Family Portrait List of artificial objects escaping from the Solar System List of missions to the outer planets New Horizons Pioneer 10 Pioneer 11 Timeline of artificial satellites and space probes Voyager 1 References Jump up ^ `` VOYAGER : Mission Information ''. NASA. 1989. Retrieved January 2, 2011. Jump up ^ `` Voyager 2 ''. US National Space Science Data Center. Retrieved 25 August 2013. Jump up ^ `` VOYAGER 2 ''. N2YO. Retrieved 25 August 2013. ^ Jump up to : Butrica, Andrew. From Engineering Science to Big Science. p. 267. Retrieved 2015 - 09 - 04. Despite the name change, Voyager remained in many ways the Grand Tour concept, though certainly not the Grand Tour ( TOPS ) spacecraft. Voyager 2 was launched on August 20, 1977, followed by Voyager 1 on September 5, 1977. The decision to reverse the order of launch had to do with keeping open the possibility of carrying out the Grand Tour mission to Uranus, Neptune, and beyond. Voyager 2, if boosted by the maximum performance from the Titan - Centaur, could just barely catch the old Grand Tour trajectory and encounter Uranus. Two weeks later, Voyager 1 would leave on an easier and much faster trajectory, visiting Jupiter and Saturn only. Voyager 1 would arrive at Jupiter four months ahead of Voyager 2, then arrive at Saturn nine months earlier. Hence, the second spacecraft launched was Voyager 1, not Voyager 2. The two Voyagers would arrive at Saturn nine months apart, so that if Voyager 1 failed to achieve its Saturn objectives, for whatever reason, Voyager 2 still could be retargeted to achieve them, though at the expense of any subsequent Uranus or Neptune encounter. Jump up ^ NASA Voyager - The Interstellar Mission Mission Overview Archived 2011 - 05 - 02 at the Wayback Machine. ^ Jump up to : Staff ( September 9, 2012 ). `` Where are the Voyagers ? ''. NASA. Retrieved September 9, 2012. Jump up ^ https://voyager.jpl.nasa.gov/mission/status/ Jump up ^ `` Voyager Mission : Weekly Reports of 26 December 2014 ''. Jump up ^ `` At last, Voyager 1 slips into interstellar space -- Atom & Cosmos ''. Science News. 2013 - 09 - 12. Retrieved 2013 - 09 - 17. Jump up ^ Planetary Voyage NASA Jet Propulsion Laboratory -- California Institute of Technology. March 23, 2004. Retrieved April 8, 2007. ^ Jump up to : `` VOYAGER 2 : Host Information ''. NASA. 1989. Retrieved January 2, 2011. Jump up ^ `` NASA News Press Kit 77 - 136 ''. JPL / NASA. Retrieved December 15, 2014. Jump up ^ `` Voyager 2 Craft Details ''. NASA - NSSDC - Spacecraft - Details. NASA. Retrieved March 9, 2011. Jump up ^ Furlong, Richard R. ; Wahlquist, Earl J. ( 1999 ). `` U.S. space missions using radioisotope power systems '' ( PDF ). Nuclear News. 42 ( 4 ) : 26 -- 34. Retrieved January 2, 2011. Jump up ^ NASA / JPL ( August 26, 2003 ). `` Voyager 1 Narrow Angle Camera Description ''. NASA / PDS. Retrieved January 17, 2011. Jump up ^ NASA / JPL ( August 26, 2003 ). `` Voyager 1 Wide Angle Camera Description ''. NASA / PDS. Retrieved January 17, 2011. Jump up ^ `` Voyager 2 Full Mission Timeline '' Muller, Daniel, 2010 Jump up ^ `` Voyager Mission Description '' NASA, February 19, 1997 Jump up ^ `` JPL Mission Information '' NASA, JPL, PDS. Jump up ^ Sullivant, Rosemary ( November 5, 2011 ). `` Voyager 2 to Switch to Backup Thruster Set ''. JPL. 2011 - 341. Jump up ^ `` Basics of space flight : Interplanetary Trajectories ''. ^ Jump up to : Henbest, Nigel ( January 31, 1985 ). `` All set to encounter Uranus ''. New Scientist. p. 24. Retrieved June 19, 2018. Jump up ^ Littmann, Mark ( 2004 ). Planets Beyond : Discovering the Outer Solar System. Courier Corporation. p. 106. Retrieved June 19, 2018. Jump up ^ Davies, John ( January 23, 1986 ). `` Voyage to the tilted planet ''. New Scientist. p. 42. Retrieved June 19, 2018. Jump up ^ `` History ''. www.jpl.nasa.gov. Jump up ^ `` NASA - NSSDCA - Master Catalog - Event Query ''. nssdc.gsfc.nasa.gov. Jump up ^ `` Voyager Steered Toward Neptune ''. Ukiah Daily Journal. 15 March 1987. Retrieved 6 December 2017. Jump up ^ `` Fact Sheet ''. JPL. Retrieved 3 March 2016. Jump up ^ Nardo 2002, p. 15 Jump up ^ `` Neptune ''. Jet Propulsion Laboratory. Retrieved 3 March 2016. Jump up ^ `` Voyager Weekly Reports ''. Voyager.jpl.nasa.gov. 2013 - 09 - 06. Retrieved 2013 - 09 - 14. Jump up ^ Notes on Voyager 2 Quick Look Data : Data after November 29, 2006 Jump up ^ `` NASA - Voyager 2 Proves Solar System Is Squashed ''. www.nasa.gov. Jump up ^ Voyager 2 finds solar system 's shape is ' dented ' # 2007 - 12 - 10, Week Ending December 14, 2007. Retrieved December 12, 2007. Jump up ^ John Antczak ( May 6, 2010 ). `` NASA working on Voyager 2 data problem ''. Associated Press. Jump up ^ `` Engineers Diagnosing Voyager 2 Data System ''. Jet Propulsion Laboratory. Retrieved May 17, 2010. Jump up ^ `` NASA Fixes Bug On Voyager 2 ''. Retrieved May 25, 2010. Jump up ^ Peat, Chris. `` Spacecraft escaping the Solar System ''. Heavens Above. Retrieved May 23, 2010. ^ Jump up to : Peat, Chris ( September 9, 2012 ). `` Spacecraft escaping the Solar System ''. Heavens - Above. Retrieved September 9, 2012. Jump up ^ `` Voyager - Fast Facts ''. voyager.jpl.nasa.gov. Jump up ^ `` At last, Voyager 1 slips into interstellar space -- Atom & Cosmos ''. Science News. 2013 - 09 - 12. Retrieved 2013 - 09 - 17. Jump up ^ `` Voyager -- Mission -- Interstellar Mission ''. NASA. June 22, 2007. Retrieved August 14, 2013. Jump up ^ `` Voyager -- Spacecraft -- Spacecraft Lifetime ''. NASA Jet Propulsion Laboratory. March 15, 2008. Retrieved May 25, 2008. Jump up ^ `` Voyager - The Spacecraft ''. voyager.jpl.nasa.gov. Jump up ^ `` Voyager -- Interstellar Science ''. NASA Jet Propulsion Laboratory. December 1, 2009. Retrieved December 2, 2009. Jump up ^ Ferris, Timothy ( May 2012 ). `` Timothy Ferris on Voyagers ' Never - Ending Journey ''. Smithsonian Magazine. Retrieved 15 June 2012. Jump up ^ `` Voyager Golden record ''. JPL. Retrieved 18 August 2013. Further reading `` Saturn Science Results ''. Voyager Science Results at Saturn. Retrieved February 8, 2005. `` Uranus Science Results ''. Voyager Science Results at Uranus. Retrieved February 8, 2005. Nardo, Don ( 2002 ). Neptune. Thomson Gale. ISBN 0 - 7377 - 1001 - 2 JPL Voyager Telecom Manual External links Wikimedia Commons has media related to : Voyager 2 ( category ) NASA Voyager website Voyager 2 Mission Profile by NASA 's Solar System Exploration Voyager 2 ( NSSDC Master Catalog ) Extremes of motion Speed Wave ( Light Sound ) Vehicle Spacecraft Aircraft propeller - based transcontinental FAI records Water - borne vehicle sailing underwater transatlantic Land vehicle ( rocket - based wheel - driven production car ( by speed / by acceleration ) railed motorcycle production motorcycle ( by speed / by acceleration ) British Distance Space ( furthest spacecraft furthest landing on another world furthest travels on another world furthest humans closest spacecraft to the Sun ) Aircraft ( furthest flight highest altitude FAI records ) Deepest Earth ocean dive Endurance Space ( most enduring spaceflight most endurance on another world most time as a person in space most enduring population of a spacecraft ) Aircraft See also Spaceflight records Voyager program Spacecraft Voyager 1 Voyager 2 Components MHW - RTG Cosmic Ray Subsystem ( CRS ) Voyager Golden Record ( Contents ) Work Pale Blue Dot Family Portrait Voyager team Stamatios Krimigis Carolyn Porco Raymond Heacock Jim Blinn Edward C. 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century space probes Active space probes ( deep space missions ) Moon ARTEMIS Longjiang - 2 Lunar Reconnaissance Orbiter Mars ExoMars TGO InSight / MarCO Mangalyaan Mars Express 2001 Mars Odyssey MAVEN MER Opportunity MRO MSL Curiosity Venus Akatsuki IKAROS Minor planet Chang'e 2 Dawn Hayabusa2 / MASCOT New Horizons OSIRIS - REx PROCYON Solar science ACE DSCOVR SOHO STEREO WIND Others Gaia Juno THEMIS Voyager 1 Voyager 2 Completed after 2000 ( by termination date ) NEAR Shoemaker Deep Space 1 2003 Pioneer 10 Galileo Nozomi Genesis 2005 Huygens 2006 Mars Global Surveyor 2008 Phoenix 2009 Chang'e 1 Ulysses Chandrayaan - 1 SELENE LCROSS Hayabusa MER Spirit 2011 Stardust 2012 GRAIL 2013 Deep Impact 2014 LADEE Venus Express Chang'e 5 - T1 2015 MESSENGER Chang'e 3 / Yutu 2016 Rosetta / Philae ExoMars Schiaparelli 2017 LISA Pathfinder Cassini List of Solar System probes List of lunar probes List of space telescopes ← 1976 Orbital launches in 1977 1978 → Kosmos 888 Meteor - 2 No. 2 Kosmos 889 Kosmos 890 NATO 3B Kosmos 891 OPS 3151 Soyuz 24 Kosmos 892 Molniya - 2 - 17 Kosmos 893 Tansei 3 Kosmos 894 Unnamed Kiku 2 Kosmos 895 Kosmos 896 Kosmos 897 Palapa A2 OPS 4915 Kosmos 898 Molniya - 1 - 36 Kosmos 899 Kosmos 900 Meteor - M No. 39 Kosmos 901 Kosmos 902 Kosmos 903 Kosmos 904 GEOS - 1 Kosmos 905 Kosmos 906 Molniya - 3 No. 19 Kosmos 907 OPS 9437 OPS 9438 Kosmos 908 Kosmos 909 Kosmos 910 OPS 9751 Kosmos 911 Kosmos 912 Intelsat IVA F - 4 Kosmos 913 Kosmos 914 OPS 5644 Kosmos 915 Kosmos 916 Kosmos 917 GOES 2 Signe 3 Kosmos 918 Kosmos 919 Kosmos 920 NTS - 2 Molniya - 1 No. 45 Kosmos 921 OPS 4800 Meteor - Priroda No. 2 - 2 Kosmos 922 Kosmos 923 Kosmos 924 Kosmos 925 Kosmos 926 Kosmos 927 Kosmos 928 Himawari 1 Kosmos 929 Kosmos 930 Kosmos 931 Kosmos 932 Kosmos 933 Gran ' No. 13L Kosmos 934 Kosmos 935 Kosmos 936 TKS - VA No. 009P TKS - VA No. 009A Unnamed HEAO - 1 Voyager 2 Kosmos 937 Kosmos 938 Kosmos 939 Kosmos 940 Kosmos 941 Kosmos 942 Kosmos 943 Kosmos 944 Kosmos 945 Kosmos 946 Sirio 1 Kosmos 947 Molniya - 1 - 38 Kosmos 948 Voyager 1 Kosmos 949 Kosmos 950 Kosmos 951 OTS - 1 Kosmos 952 Kosmos 953 Kosmos 954 Kosmos 955 Ekran No. 12L Prognoz 6 OPS 7471 Kosmos 956 Interkosmos 17 Salyut 6 Intelsat IVA F - 5 Kosmos 957 Soyuz 25 Kosmos 958 Kosmos 959 ISEE - 1 ISEE - 2 Kosmos 960 Kosmos 961 Molniya - 3 No. 18 Transat Kosmos 962 Meteosat 1 Kosmos 963 Unnamed Kosmos 964 Kosmos 965 OPS 8781 OPS 8781 SSU - 1 OPS 8781 SSU - 2 OPS 8781 SSU - 3 Soyuz 26 OPS 4258 Kosmos 966 Kosmos 967 Meteor - 2 No. 3 Sakura 1 Kosmos 968 Kosmos 969 Kosmos 970 Kosmos 971 Kosmos 972 Kosmos 973 Payloads are separated by bullets ( ), launches by pipes ( ). Manned flights are indicated in bold text. Uncatalogued launch failures are listed in italics. Payloads deployed from other spacecraft are denoted in ( brackets ). 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Question: what did the voyager 2 discover about neptune
Answer: the "Great Dark Spot"