On August 20th, 1977, Voyager 2 was launched. Her sister spacecraft, Voyager 1, followed two weeks later. The goal of these two explorers was to shed light on the mysteries of our solar system by getting up close and personal with our planetary neighbours.
Artist’s concept of Voyager in flight.
The missions scope and engineering ingenuity have yet to be matched and forty years later, both the pioneering craft are still operating, sending back data, and heading on their way out of our solar system to explore further than any spacecraft ever launched.
The spacecraft was built with 3 Multihundred-Watt radioisotope thermoelectric generators (MHW RTG). Each RTG includes 24 pressed plutonium oxide spheres and provides enough heat to generate approximately 157 watts of power at launch. Collectively, the RTGs supply the spacecraft with 470 watts at launch and will allow operations to continue until at least 2020
29 July 1977 – Gold-Plated Record is attached to Voager 1. The title of the record is Sound of Earth
2 August 1977 – The 1800 pound heavy Voyager 2 spaceprobe is encapsulated for the launch to the planets Jupiter and Saturn. Later the mission was extended to the planets Uranus and Neptun
Voyager Golden Record – The Voyager Golden Records are phonograph records that were included aboard both Voyager spacecraft launched in 1977. The records contain sounds and images selected to portray the diversity of life and culture on Earth, and are intended for any intelligent extraterrestrial life form, or for future humans, who may find them
Planetary Grand Tour
The mission was driven, in part, by a rare planetary alignment which occurred in the late 1970s. Jupiter, Saturn, Uranus, Neptune and Pluto perfectly align every 175 years – NASA engineers took advantage of this to propel the craft quickly between most of the Solar System’s outer planets using gravitational slingshots to leap from planet to planet.
The name of the Voyager project came only a few months before launch in 1977. The clunkily named ‘Mariner Jupiter-Saturn mission’ was renamed in a public competition to ‘Voyager’ and the two Voyager probes were launched in August and September 1977.
August 20, 1977 – The Voyager 2 aboard Titan III-Centaur launch vehicle lifted off on August 20, 1977. The Voyager 2 was a scientific satellite to study the Jupiter and the Saturn planetary systems including their satellites and Saturn’s rings.
Where no probe has gone before – Encounter with Jupiter
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
July 1979 – This picture shows a region of the southern hemisphere extending from the Great Red Spot to the south pole. The white oval is seen beneath the Great Red Spot, and several small scale spots are visible farther to the south. Some of these organized cloud spots have similar morphologies, such as anticyclonic rotations and cyclonic regions to their west. The presence of the white oval causes the streamlines of the flow to bunch up between it and the Great Red Spot.
9 July 1979 – Jupiter and Io photographed by the Voyager 2 probe.
An Eruption on Io, photographed by Voyager 2
This mosaic of Europa, the smallest Galilean satellite, was taken by Voyager 2. This face of Europa is centered at about the 300 degree meridian. The bright areas are probably ice deposits, whereas the darkened areas may be the rocky surface or areas with a more patchy distribution of ice. The most unusual features are the systems of long linear structures that cross the surface in various directions. Some of these linear structures are over 1,000 kilometers long and about 2 or 3 kilometers wide. They may be fractures or faults which have disrupted the surface.
The hemisphere of Ganymede that faces away from Jupiter displays a great variety of terrain. In this Voyager 2 mosaic, photographed at a range of 300,000 kilometres, the ancient dark area of Regio Galileo lies at the upper right.
Below it, the ray system is probably caused by water-ice, splashed out in a relatively recent impact.
The original NASA image has been cropped, and some non-full-color areas have been blacked out.
7 July 1979 – This false color picture of Callisto was taken by Voyager 2 on July 7, 1979 at a range of 1,094,666 kilometers (677,000 miles) and is centered on 11 degrees N and 171 degrees W. This rendition uses an ultraviolet image for the blue component. Because the surface displays regional contrast in UV, variations in surface materials are apparent. Notice in particular the dark blue haloes which surround bright craters in the eastern hemisphere. The surface of Callisto is the most heavily cratered of the Galilean satellites and resembles ancient heavily cratered terrains on the moon, Mercury and Mars. The bright areas are ejecta thrown out by relatively young impact craters. A large ringed structure, probably an impact basin, is shown in the upper left part of the picture. The color version of this picture was constructed by compositing black and white images taken through the ultraviolet, clear and orange filters.
11 July 1979 – Voyager 2 captures Jupiters rings (that’s right – Jupiter has rings)
6 May 1979 – An eruptive event in the southern hemisphere of Jupiter over a period of 8 Jupiter days. Prior to the event, an undistinguished oval cloud mass cruised through the turbulent atmosphere. The eruption occurs over a very short time at the very center of the cloud. The white eruptive material is swirled about by the internal wind patterns of the cloud. As a result of the eruption, the cloud then becomes a type of feature seen elsewhere on Jupiter known as “spaghetti bowls.”
As Voyager 2 approached Jupiter in 1979, it took images of the planet at regular intervals. This sequence is made from 8 images taken once every Jupiter rotation period (about 10 hours). These images were acquired in the Violet filter around May 6, 1979. The spacecraft was about 50 million kilometers from Jupiter at that time.
This time-lapse movie was produced at JPL by the Image Processing Laboratory in 1979
Next Stop Saturn
The closest approach to Saturn occurred on August 26, 1981. Voyager 2 returned scientific data via radio link about everything from the planets atmospheric temperature to density profiles.
This true color picture was assembled from Voyager 2 Saturn images obtained Aug. 4  from a distance of 21 million kilometers (13 million miles) on the spacecraft’s approach trajectory. Three of Saturn’s icy moons are evident at left. They are, in order of distance from the planet: Tethys, 1,050 km. (652 mi.) in diameter; Dione, 1,120 km. (696 mi.); and Rhea, 1,530 km. (951 mi.). The shadow of Tethys appears on Saturn’s southern hemisphere. A fourth satellite, Mimas, is less evident, appearing as a bright spot a quarter-inch in in from the planet’s limb about half an inch above Tethys; the shadow of Mimas appears on the planet about three-quarters of an inch directly above that of Tethys. The pastel and yellow hues on the planet reveal many contrasting bright and darker bands in both hemispheres of Saturn’s weather system. The Voyager project is managed for NASA by the Jet Propulsion Laboratory, Pasadena, California, United States
The north polar region of Saturn is pictured in great detail in this Voyager 2 image obtained Aug. 25 from a range of 633,000 kilometers (393,000 miles).
Two oval cloud systems some 250 km (150 mi) across are visible at about 72 degrees north latitude. The bright spot in the center of the leftmost cloud is a convective cloud storm about 60 km. (37 mi.)across. The outer ring of material rotates in an anti-cyclonic sense(counterclockwise in the northern hemisphere). A similar cloud structure of comparable dimension appears at 55 degrees north (bottom center of this picture). These northern latitudes contain many bright, small-scale cloud spots–only a few tens of kilometers across–representative of convective cloud systems. Across the top of this image stretch several long, linear, wavelike features that may mark the northernmost east-flowing jet in Saturn’s atmosphere.
In this orange-and-violet-image composite, the smallest features visible are about 16 km. (10 mi.) across.
This Voyager 2 mosaic of Enceladus was made from images taken through the clear, violet and green filters Aug. 25, 1981, from a distance of 119,000 kilometers (74,000 miles).
In many ways, the surface of this satellite of Saturn resembles that of Jupiter’s Galilean satellite Ganymede. Enceladus, however, is only one-tenth Ganymede’s size. Some regions of Enceladus show impact craters up to 35 kilometers (22 miles) in diameter, whereas other areas are smooth and uncratered. Linear sets of grooves tens of kilometers long traverse the surface and are probably faults resulting from deformation of the crust. The uncratered regions are geologically young and suggest that Enceladus has experienced a period of relatively recent internal melting. The rims of several craters near the lower center of the picture have been flooded by the smooth terrain. The satellite is about 500 kilometers (310 miles) in diameter and has the brightest and whitest surface of any of Saturn’s satellites.
Features as small as 2 kilometers (1.2 miles) are visible in this highest-resolution view of Enceladus
Voyager 2 obtained this image of Tethys on Aug. 25, when the spacecraft was 594,000 kilometers (368,000 miles) from this satellite of Saturn. This photograph was compiled from images taken through the violet, clear and green filters of Voyager’s narrow-angle camera. Tethys shows two distinct types of terrain–bright, densely cratered regions; and relatively dark, lightly cratered planes that extend in a broad belt across the satellite. The densely cratered terrain is believed to be part of the ancient crust of the satellite; the lightly cratered planes are thought to have been formed later by internal processes. Also clearly seen is a trough that runs parallel to the terminator (the day-night boundary, seen at right). This trough is an extension of the huge canyon system Voyager 1 saw last fall. This system extends nearly two-thirds the distance around Tethys.
This Voyager 2 photograph of Titan, taken Aug. 23 from a range of 2.3 million kilometers (1.4 million miles), shows some detail in the cloud systems on this Saturnian moon.
The southern hemisphere appears lighter in contrast, a well-defined band is seen near the equator, and a dark collar is evident at the north pole. All these bands are associated with cloud circulation in Titan’s atmosphere. The extended haze, composed of submicron-size particles, is seen clearly around the satellite’s limb.
This image was composed from blue, green and violet frames.
This Voyager 2 narrow-angle camera image of Titan was taken through the Clear filter from a distance of 0.9 million km on 25 August 1981. With a phase angle of 155 degrees, the thick atmosphere can be seen illuminated completely around the disk. A distinct upper haze layer is present over much of the circumference of the disk.
August 22, 1981 – Saturn’s outermost large moon, Iapetus, has a bright, heavily cratered icy terrain and a dark terrain, as shown in this Voyager 2 image taken on August 22, 1981. Amazingly, the dark material covers precisely the side of Iapetus that leads in the direction of orbital motion around Saturn (except for the poles), whereas the bright material occurs on the trailing hemisphere and at the poles. The bright terrain is made of dirty ice, and the dark terrain is surfaced by carbonaceous molecules, according to measurements made with Earth-based telescopes. Iapetus’ dark hemisphere has been likened to tar or asphalt and is so dark that no details within this terrain were visible to Voyager 2. The bright icy hemisphere, likened to dirty snow, shows many large impact craters. The closest approach by Voyager 2 to Iapetus was a relatively distant 600,000 miles, so that our best images, such as this, have a resolution of about 12 miles. The dark material is made of organic substances, probably including poisonous cyano compounds such as frozen hydrogen cyanide polymers. Though we know a little about the dark terrain’s chemical nature, we do not understand its origin. Two theories have been developed, but neither is fully satisfactory–(1) the dark material may be organic dust knocked off the small neighboring satellite Phoebe and “painted” onto the leading side of Iapetus as the dust spirals toward Saturn and Iapetus hurtles through the tenuous dust cloud, or (2) the dark material may be made of icy-cold carbonaceous “cryovolcanic” lavas that were erupted from Iapetus’ interior and then blackened by solar radiation, charged particles, and cosmic rays. A determination of the actual cause, as well as discovery of any other geologic features smaller than 12 miles across, awaits the Cassini Saturn orbiter to arrive in 2004
22 August 1981 – Voyager 2 obtained this high-resolution picture of Saturn’s rings Aug. 22, 1981, when the spacecraft was 4 million kilometers (2.5 million miles) away. Evident here are the numerous “spoke” features, in the B-ring; their very sharp, narrow appearance suggests short formation times. Scientists think electromagnetic forces are responsible in some way for these features, but no detailed theory has been worked out. Pictures such as this and analyses of Voyager 2’s spoke movies may reveal more clues about the origins of these complex structures
The fly-by of Saturn almost ended Voyagers 2 mission.
The camera platform used by the spacecraft locked up, but engineers on the ground were able to remotely fix the problem which had been caused by the overuse (temporarily depleted the system’s lubricant)
Voyager 2 was given the go-ahead to explore the Uranian system.
A first look at the Uranian system
The closest approach to Uranus occurred on January 24, 1986, when Voyager 2 came within 81,500 kilometres (50,600 mi) of the planet’s cloud tops.
The fly-by resulted in the discovery of the moons Cordelia, Ophelia, Bianca, Cressida, Desdemona, Juliet, Portia, Rosalind, Belinda, Perdita and Puck.
22 January 1986 – Voyager 2 picture of Uranus’ rings taken on January 22, 1986, from a distance of 2.52 million kilometers. Nine rings are visible in this image, a 15-second exposure through a clear filter. The most prominent and outermost of the nine, called epsilon, is seen at top. The next three in toward Uranus — called delta, gamma and eta — are much fainter and more narrow than the epsilon ring. Then come the beta and alpha rings and finally the innermost grouping, known simply as the 4, 5 and 6 rings. The last three are very faint and are at the limit of detection for the Voyager camera. The bright dots are imperfections on the camera detector. The resolution scale is approximately 50 km (30 mi).
16 December 1986 – An image of the planet Uranus taken by the spacecraft Voyager 2
This view of Uranus was recorded by Voyager 2 on Jan 25, 1986, as the spacecraft left the planet behind and set forth on the cruise to Neptune Voyager was 1 million kilometers (about 600,000 miles) from Uranus when it acquired this wide-angle view. The picture — a color composite of blue, green and orange frames — has a resolution of 140 km (90 mi). The thin crescent of Uranus is seen here at an angle of 153 degrees between the spacecraft, the planet and the Sun. Even at this extreme angle, Uranus retains the pale blue-green color seen by ground-based astronomers and recorded by Voyager during its historic encounter. This color results from the presence of methane in Uranus’ atmosphere; the gas absorbs red wavelengths of light, leaving the predominant hue seen here. The tendency for the crescent to become white at the extreme edge is caused by the presence of a high-altitude haze Voyager 2 — having encountered Jupiter in 1979, Saturn in 1981 and Uranus in 1986 — will proceed on its journey to Neptune. Closest approach is scheduled for Aug 24, 1989. The Voyager project is managed for NASA by the Jet Propulsion Laboratory.
January 24, 1986 – Miranda reveals a complex geologic history in this view, acquired by Voyager 2 on January 24, 1986, around its close approach to the Uranian moon. At least three terrain types of different age and geologic style are evident at this resolution of about 700 meters (2,300 feet). Visible in this clear-filter, narrow-angle image are, from left: (1) an apparently ancient, cratered terrain consisting of rolling, subdued hills and degraded medium-sized craters (2) a grooved terrain with linear valleys and ridges developed at the expense of, or replacing, the first terrain type: and (3) a complex terrain seen along the terminator, in which intersecting curvilinear ridges and troughs are abruptly truncated by the linear, grooved terrain. Voyager scientists believe this third terrain type is intermediate in age between the first two.
This picture is part of the highest-resolution Voyager 2 imaging sequence of Ariel, a moon of Uranus about 1,300 kilometers (800 miles) in diameter. The clear-filter, narrow-angle image was taken Jan. 24, 1986, from a distance of 130,000 km (80,000 mi). The complexity of Ariel’s surface indicates that a variety of geologic processes have occurred. The numerous craters, for example, are indications of an old surface bombarded by meteoroids over a long period. Also conspicuous at this resolution, about 2.4 km (1.5 mi), are linear grooves (evidence of tectonic activity that has broken up the surface) and smooth patches (indicative of deposition of material).
24 January 1986 – This high-resolution color composite of Titania was made from Voyager 2 images taken Jan. 24, 1986, as the spacecraft neared its closest approach to Uranus. Voyager’s narrow-angle camera acquired this image of Titania, one of the large moons of Uranus, through the violet and clear filters. The spacecraft was about 500,000 kilometers (300,000 miles) away; the picture shows details about 9 km (6 mi) in size. Titania has a diameter of about 1,600 km (1,000 mi). In addition to many scars due to impacts, Titania displays evidence of other geologic activity at some point in its history. The large, trenchlike feature near the terminator (day-night boundary) at middle right suggests at least one episode of tectonic activity. Another, basinlike structure near the upper right is evidence of an ancient period of heavy impact activity. The neutral gray color of Titania is characteristic of the Uranian satellites as a whole. The Voyager project is managed for NASA by the Jet Propulsion Laboratory
The southern hemisphere of Umbriel displays heavy cratering in this Voyager 2 image, taken Jan. 24, 1986, from a distance of 557,000 kilometers (346,000 miles). This frame, taken through the clear-filter of Voyager’s narrow-angle camera, is the most detailed image of Umbriel, with a resolution of about 10 km (6 mi). Umbriel is the darkest of Uranus’ larger moons and the one that appears to have experienced the lowest level of geological activity. It has a diameter of about 1,200 km (750 mi) and reflects only 16 percent of the light striking its surface; in the latter respect, Umbriel is similar to lunar highland areas. Umbriel is heavily cratered but lacks the numerous bright ray craters seen on the other large Uranian satellites; this results in a relatively uniform surface albedo (reflectivity). The prominent crater on the terminator (upper right) is about 110 km (70 mi) across and has a bright central peak. The strangest feature in this image (at top) is a curious bright ring, the most reflective area seen on Umbriel. The ring is about 140 km (90 miles) in diameter and lies near the satellite’s equator. The nature of the ring is not known, although it might be a frost deposit, perhaps associated with an impact crater. Spots against the black background are due to ‘noise’ in the data. The Voyager project is managed for NASA by the Jet Propulsion Laboratory.
February 1986 – A reprojected view of Oberon
Last Official Stop – Neptune
Voyager 2’s closest approach to Neptune occurred on August 25, 1989.
This was the last planet of the Solar System 2 which the probes would visit. The Chief Project Scientist, his staff members, and the flight controllers decided to also perform a close fly-by of Triton.
Voyager 2 discovered the “Great Dark Spot”, which has since disappeared, according to observations by the Hubble Space Telescope. It was hypothesized to be a hole in the visible cloud deck of Neptune.
The decision in 2006 by the International Astronomical Union to reclassify Pluto as a “dwarf planet” means that 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.
Two 591-second exposures of the rings of Neptune were taken with the clear filter by the Voyager 2 wide-angle camera on Aug. 26, 1989 from a distance of 280,000 kilometers (175,000 miles).
August 1989 – This picture of Neptune was produced from the last whole planet images taken through the green and orange filters on the Voyager 2 narrow angle camera. The images were taken at a range of 4.4 million miles from the planet, 4 days and 20 hours before closest approach in August 1989. The picture shows the Great Dark Spot and its companion bright smudge; on the west limb the fast moving bright feature called Scooter and the little dark spot are visible. These clouds were seen to persist for as long as Voyager’s cameras could resolve them. North of these, a bright cloud band similar to the south polar streak may be seen.
28 August 1989 – This dramatic view of the crescents of Neptune and Triton was acquired by Voyager 2 approximately 3 days, 6 and one-half hours after its closest approach to Neptune (north is to the right). The spacecraft is now plunging southward at an angle of 48 degrees to the plane of the ecliptic. This direction, combined with the current season of southern summer in the Neptune system, gives this picture its unique geometry. The spacecraft was at a distance of 4.86 million kilometers (3 million miles) from Neptune when these images were shuttered so the smallest detail discernible is approximately 90 kilometers (56 miles). Color was produced using images taken through the narrow-angle camera’s clear, orange and green filters. Neptune does not appear as blue from this viewpoint because the forward scattering nature of its atmosphere is more important than its absorption of red light at this high phase angle (134 degrees).
Despina as seen by Voyager 2. There is significant horizontal smearing due to the combination of long exposure needed at this distance from the Sun, and the rapid relative motion of the moon and Voyager.
These Voyager 2 images of satellite Larissa at a resolution of 4.2 kilometers (2.6 miles) per pixel reveal it to be and irregularly shaped, dark object. The satellite appears to have several craters 30 to 50 kilometers (18.5 to 31 miles) across. The irregular outline suggests that this moon has remained cold and rigid throughout much of its history. It is about 210 by 190 kilometers (130 by 118 miles), about half the size of Proteus. It has a low albedo surface reflecting about 5 percent of the incident light. The Voyager Mission is conducted by JPL for NASA’s Office of Space Science and Applications.
25 August 1989 – Proteus is the second largest moon of Neptune behind the mysterious Triton. Proteus was discovered only in 1989 by the Voyager 2 spacecraft. This is unusual since Neptune has a smaller moon – Nereid – which was discovered 33 years earlier from Earth. The reason Proteus was not discovered sooner is that its surface is very dark and it orbits much closer to Neptune. Proteus has an odd box-like shape and were it even slightly more massive, its own gravity would cause it to reform itself into a sphere.
25 August 1989 – Global colour mosaic of Triton, taken in 1989 by Voyager 2 during its flyby of the Neptune system. The color was synthesized by combining high-resolution images taken through orange, violet, and ultraviolet filters; these images were displayed as red, green, and blue images and combined to create this color version. With a radius of 1,350 km (839 mi), about 22% smaller than Earth’s moon, Triton is by far the largest satellite of Neptune. It is one of only three objects in the Solar System known to have a nitrogen-dominated atmosphere (the others are Earth and Saturn’s giant moon, Titan). Triton has the coldest surface known anywhere in the Solar System (38 K, about -391 degrees Fahrenheit); it is so cold that most of Triton’s nitrogen is condensed as frost, making it the only satellite in the Solar System known to have a surface made mainly of nitrogen ice. The pinkish deposits constitute a vast south polar cap believed to contain methane ice, which would have reacted under sunlight to form pink or red compounds. The dark streaks overlying these pink ices are believed to be an icy and perhaps carbonaceous dust deposited from huge geyser-like plumes, some of which were found to be active during the Voyager 2 flyby. The bluish-green band visible in this image extends all the way around Triton near the equator; it may consist of relatively fresh nitrogen frost deposits. The greenish areas include what is called the cantaloupe terrain, whose origin is unknown, and a set of “cryovolcanic” landscapes apparently produced by icy-cold liquids (now frozen) erupted from Triton’s interior.
25 August 1989 -This Voyager 2 high resolution color image, taken 2 hours before closest approach, provides obvious evidence of vertical relief in Neptune’s bright cloud streaks.
These clouds were observed at a latitude of 29 degrees north near Neptune’s east terminator. The linear cloud forms are stretched approximately along lines of constant latitude and the Sun is toward the lower left. The bright sides of the clouds which face the Sun are brighter than the surrounding cloud deck because they are more directly exposed to the sun. Shadows can be seen on the side opposite the sun. These shadows are less distinct at short wavelengths (violet filter) and more distinct at long wavelengths (orange filter). This can be understood if the underlying cloud deck on which the shadow is cast is at a relatively great depth, in which case scattering by molecules in the overlying atmosphere will diffuse light into the shadow.
Because molecules scatter blue light much more efficiently than red light, the shadows will be darkest at the longest (reddest) wavelengths, and will appear blue under white light illumination.
The resolution of this image is 11 kilometers (6.8 miles per pixel) and the range is only 157,000 kilometers (98,000 miles). The width of the cloud streaks range from 50 to 200 kilometers (31 to 124 miles), and their shadow widths range from 30 to 50 kilometers (18 to 31 miles). Cloud heights appear to be of the order of 50 kilometers (31 miles).
Solar to Interstellar
Once its planetary mission was over, Voyager 2 was described as working on an interstellar mission.
February 14, 1990 – The “family portrait” of the Solar System taken by Voyager 1 from a distance of ~6 billion km’s from Earth
It features individual frames of six planets and a partial background indicating their relative positions. The picture is a mosaic of 60 individual frames taken through the Wide Angle and Narrow Angle cameras using the Methane, Violet, Blue, Green, and Clear Filters.
NASA is now using the craft to find out what the Solar System is like beyond the heliosphere and Voyager 2 is currently transmitting scientific data at about 160 bits per second.
Voyager 1 crossed into interstellar space in 2012. Voyager 2 should enter interstellar space in late 2019 or early 2020.
Voyager 2 is not headed toward any particular star, but in ~40,000 years it should pass 1.7 light-years from the star Ross 248. She is expected to keep transmitting weak radio messages until at least 2025, over 48 years after her launch.