Voyager 2 facts for kids

Quick facts for kids
Voyager 2

Artist's rendering of the Voyager spacecraft design
Mission type	Planetary exploration
Operator	NASA / JPL
Mission duration	Total:  48 years, 7 months, 28 days (elapsed) Planetary mission:  12 years, 1 month, 12 days Interstellar mission:  36 years, 6 months, 15 days (elapsed)
Spacecraft properties
Manufacturer	Jet Propulsion Laboratory
Launch mass	721.9 kg (1,592 lb)
Power	470 watts (at launch)
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
Distance	570,000 kilometers (350,000 mi)
Flyby of Saturn
Closest approach	August 26, 1981
Distance	101,000 km (63,000 mi)
Flyby of Uranus
Closest approach	January 24, 1986
Distance	81,500 km (50,600 mi)
Flyby of Neptune
Closest approach	August 25, 1989
Distance	4,951 km (3,076 mi)
Large Strategic Science Missions Planetary Science Division ← Viking 2 Voyager 1 →

The Voyager 2 spacecraft is a robotic explorer launched by NASA on August 20, 1977. It is part of the Voyager program, designed to study the outer planets of our Solar System. Voyager 2 is special because it is the only spacecraft to have visited the ice giant planets, Uranus and Neptune.

This amazing probe was the third of five spacecraft to gain enough speed to leave the Solar System. It launched 16 days before its twin, Voyager 1. Its main job was to explore the outer planets. Now, its extended mission is to study the space between stars, far beyond the Sun's influence.

Voyager 2 successfully completed its primary mission. It visited Jupiter in 1979, Saturn in 1981, Uranus in 1986, and Neptune in 1989. The spacecraft is currently exploring the interstellar medium, which is the material and energy found between star systems. It is currently about 143 billion kilometers (89 billion miles) from Earth.

On November 5, 2018, the probe officially entered the interstellar medium. This means it crossed the boundary where the Sun's influence ends. Voyager 2 joined Voyager 1, which reached this area in 2012. It has started sending back the first direct measurements of the density and temperature of the plasma in interstellar space.

Voyager 2 communicates with Earth using NASA Deep Space Network antennas. The Canberra Deep Space Communication Complex in Australia is responsible for these communications.

History of the Voyager 2 Mission

Planning the Grand Tour

In the early days of space exploration, scientists realized something exciting. The outer planets would line up in a special way in the late 1970s. This rare alignment would allow a single spacecraft to visit Jupiter, Saturn, Uranus, and Neptune. It could do this by using a trick called "gravity assist". This technique uses a planet's gravity to speed up and change the direction of a spacecraft.

NASA started planning a "Grand Tour" mission. This project involved two pairs of probes. One pair would visit Jupiter, Saturn, and Pluto. The other would visit Jupiter, Uranus, and Neptune. The spacecraft were designed to be very tough to survive the long journey.

By 1972, the mission plans were simplified. It became the Mariner Jupiter-Saturn probes. The main goal was to fly past Jupiter and Saturn. However, the design kept the option open to continue to Uranus and Neptune. Later, the program was renamed "Voyager".

Voyager 1 and Voyager 2 Missions

The main goal for Voyager 1 was to explore Jupiter, Saturn, and Saturn's largest moon, Titan. Voyager 2 also explored Jupiter and Saturn. But its path was set up so it could continue to Uranus and Neptune. It could also be redirected to Titan if Voyager 1 had problems.

After Voyager 1 successfully completed its tasks, Voyager 2 got an extended mission. This allowed it to travel onward to Uranus and Neptune. Titan was a key target because images from Pioneer 11 in 1979 showed it had a thick and complex atmosphere.

How Voyager 2 Was Built

The Jet Propulsion Laboratory (JPL) built Voyager 2. The spacecraft's main body is shaped like a ten-sided prism. It has 16 small hydrazine thrusters. These help it stay stable and point its large antenna towards Earth. It also uses gyroscopes and star trackers to keep its direction.

The spacecraft also carried 11 scientific instruments. These tools helped it study planets and other objects in space.

How Voyager 2 Talks to Earth

Voyager 2 was built to travel far into space. It has a large, 3.7-meter (12-foot) dish antenna. This antenna sends and receives data from the Deep Space Network on Earth. It uses radio waves to communicate.

The data speed was very fast near Jupiter, up to 115.2 kilobits per second. But as the spacecraft traveled farther, the speed decreased. This is because radio signals get weaker over long distances. When the spacecraft cannot talk to Earth, it records data on a digital tape recorder. This recorder can hold about 64 megabytes of data.

Powering the Journey

Voyager RTG unit

Voyager 2 gets its power from three special generators. They are called multihundred-watt radioisotope thermoelectric generators (RTGs). Each RTG uses plutonium oxide spheres to create heat. This heat is then turned into electricity.

At launch, the RTGs provided 470 watts of power. This power slowly decreases over time. These generators were expected to keep the spacecraft working until at least 2020. They continued to power five science instruments into early 2023. In April 2023, engineers started using a backup power source. This allowed the five instruments to keep working. In October 2024, the plasma science instrument was turned off to save power for the remaining four.

Steering in Space

To reach Jupiter, the spacecraft needed a lot of energy. It had a special propulsion module with a solid-rocket motor. This module also had eight hydrazine engines for steering. Four engines controlled pitch and yaw, and four controlled roll. This module was dropped off after the Jupiter burn.

Sixteen smaller hydrazine thrusters on the main spacecraft help control its direction. Four are used for big course corrections. The others work in two groups to keep the spacecraft stable. Only one group of thrusters is needed at a time.

A single tank held 100 kg (220 lb) of hydrazine fuel at launch. This fuel was expected to last until 2034.

Science Tools on Board

Voyager 2 carries several instruments to study space. Here are some of them:

Voyager 2 Mission Journey

Key Moments in Voyager 2 Travel

Launch and Early Journey

Voyager 2 launched on August 20, 1977, from Cape Canaveral, Florida. It rode into space on a Titan IIIE/Centaur rocket. Its twin, Voyager 1, launched two weeks later. However, Voyager 1 reached Jupiter and Saturn first. This was because Voyager 2 was sent on a longer, more circular path.

In April 1978, Voyager 2 had a problem. Its main radio receiver stopped working. The spacecraft switched to its backup receiver. This backup receiver could only hear signals sent at a very specific frequency. This frequency changed due to Earth's rotation and the spacecraft's temperature.

Visiting Jupiter

Animation of Voyager 2's trajectory around Jupiter.       Voyager 2 ·       Jupiter ·       Io ·       Europa ·       Ganymede ·       Callisto

The path of Voyager 2 through the Jovian system.

Voyager 2 flew closest to Jupiter on July 9, 1979. It came within 570,000 kilometers (354,000 miles) of the planet's cloud tops. The mission revealed that Jupiter's Great Red Spot is a huge, complex storm. It also found smaller storms and swirling clouds.

Voyager 2 sent back images of Jupiter and its moons: Amalthea, Io, Callisto, Ganymede, and Europa. It confirmed that Io has active volcanoes, just like Voyager 1 had seen. The two Voyager probes together observed nine volcanic eruptions on Io.

Jupiter's moon Europa showed many crisscrossing lines in the photos. Scientists first thought these were deep cracks. But closer pictures from Voyager 2 showed they were flat, like lines drawn with a marker. Europa is thought to have a thin crust of water ice, possibly floating on a deep ocean.

Voyager 2 also discovered two new, small moons, Adrastea and Metis. They orbit just outside Jupiter's ring. A third new moon, Thebe, was found between Amalthea and Io.

Exploring Saturn

Voyager 2 made its closest approach to Saturn on August 26, 1981. As it passed behind Saturn, its radio signals helped scientists study Saturn's upper atmosphere. They gathered data on temperature and pressure. In the highest parts of the atmosphere, the temperature was about -191°C (-312°F). Deeper down, it rose to about -130°C (-202°F).

After leaving Saturn, Voyager 2 had a problem with its scan platform. This part of the spacecraft helps point instruments. It temporarily stopped working. Engineers on Earth worked hard to fix it. They sent commands that allowed the platform to move again. Because of this issue, Voyager 2 did not fly close to Titan. Instead, it continued its journey to Uranus.

Discovering Uranus

Voyager 2 flew closest to Uranus on January 24, 1986. It came within 81,500 kilometers (50,600 miles) of the planet's cloud tops. During this visit, Voyager 2 discovered 11 new moons around Uranus. These included Cordelia, Ophelia, Bianca, Cressida, Desdemona, Juliet, Portia, Rosalind, Belinda, Puck, and Perdita.

The mission also studied Uranus's unique atmosphere. This atmosphere is affected by the planet's extreme tilt of 97.8 degrees. Voyager 2 found that a day on Uranus lasts 17 hours and 14 minutes. It also discovered that Uranus has a magnetic field that is tilted compared to its rotation. This was different from other planets visited so far.

Images from Voyager 2 showed that Uranus had a layer of haze covering most of its clouds. However, enhanced images revealed bands of clouds around its south pole. This area also glowed brightly in ultraviolet light. The average temperature in the atmosphere is about -213°C (-351°F).

Detailed images of Uranus's moon Miranda showed huge canyons. One idea is that Miranda might have been shattered by a huge impact long ago. Then, its pieces came back together.

Voyager 2 also found two new rings around Uranus. These rings are different from those around Jupiter and Saturn. Scientists think the Uranian rings might be quite young. They may have formed from a moon that broke apart.

In March 2020, scientists re-examined old data from Voyager 2. They found evidence of a large magnetic bubble, called a plasmoid, escaping from Uranus into space.

Encounter with Neptune

Voyager 2 made its closest approach to Neptune on August 25, 1989. Flight controllers carefully planned its path. They directed Voyager 2 to pass about 4,950 kilometers (3,076 miles) above Neptune's north pole. Five hours later, it flew close to Triton, Neptune's largest moon. It passed within about 40,000 kilometers (25,000 miles) of Triton.

Voyager 2 discovered previously unknown Neptunian rings. It also confirmed six new moons: Despina, Galatea, Larissa, Proteus, Naiad, and Thalassa. While near Neptune, Voyager 2 found a feature called the "Great Dark Spot". This spot has since disappeared, according to observations from the Hubble Space Telescope. Scientists believe it was a clear area in Neptune's high-altitude methane clouds.

Journey into Interstellar Space

Voyager 2 left the heliosphere on November 5, 2018.

Voyager 1 and 2 speed and distance from Sun.

After its planetary mission, Voyager 2 began its interstellar mission. NASA uses it to learn about the space beyond our Solar System. Currently, Voyager 2 is transmitting scientific data at about 160 bits per second. You can find updates on its communications in the Voyager Weekly Reports.

NASA map showing trajectories of the Pioneer 10, Pioneer 11, Voyager 1, and Voyager 2 spacecraft.

In 1992, Voyager 2 observed a nova (a sudden brightening of a star) called V1974 Cygni. This was the first time such an event was seen in far-ultraviolet light. This helped scientists study the nova in more detail.

In July 1994, scientists tried to use Voyager 2 to observe comet Comet Shoemaker–Levy 9 impacting Jupiter. The spacecraft was in a good position to see the impacts. However, it did not detect anything. Calculations showed the fireballs were just too faint for the probe to see.

On November 29, 2006, a command sent to Voyager 2 was misunderstood by its computer. This caused the heaters for the spacecraft's magnetometer to turn on. These heaters stayed on until December 4, 2006. The temperature rose very high, much hotter than the magnetometers were designed for.

On August 30, 2007, Voyager 2 crossed the termination shock. It then entered the heliosheath. This was about 1.6 billion kilometers (1 billion miles) closer to the Sun than Voyager 1 did. This difference is due to the magnetic field of deep space.

In April 2010, Voyager 2 had problems with its scientific data format. On May 17, 2010, JPL engineers found that a "flipped bit" in an onboard computer caused the issue. They fixed it on May 19, and Voyager 2 resumed sending data.

It was once thought that Voyager 2 would enter interstellar space in two to three years from 2013. Scientists expected its plasma spectrometer to provide the first direct measurements of interstellar plasma. However, they needed more evidence, like a shift in the magnetic field direction. Finally, in December 2018, it was announced that Voyager 2 reached interstellar space on November 5, 2018.

The position of Voyager 2 in December 2018. Earth is 1 AU from the Sun; Saturn is at 10 AU, and the heliopause is around 120 AU. Neptune is 30.1 AU from the Sun.

Maintenance work on the Deep Space Network stopped contact with the probe for eight months in 2020. Contact was restored on November 2, 2020. Full communications were back on February 12, 2021, after a year-long upgrade to a ground station antenna.

In October 2020, astronomers reported an unexpected increase in density in the space beyond the Solar System. Both Voyager 1 and Voyager 2 detected this. This suggests a large-scale feature in the very local interstellar medium.

On July 18, 2023, Voyager 2 became the second farthest spacecraft from the Sun, passing Pioneer 10.

On July 21, 2023, a programming error caused Voyager 2's main antenna to point 2 degrees away from Earth. This broke communications. By August 1, the spacecraft's signal was detected. On August 4, a powerful "shout" from the Canberra Deep Space Communication Complex successfully commanded the spacecraft to reorient itself. Communications were restored. As a backup, the probe is programmed to reset its orientation automatically, which would have happened by October 15, 2023.

Reducing Capabilities to Save Power

As the power from the RTGs slowly decreases, some equipment on the spacecraft has been turned off. The first science instrument turned off on Voyager 2 was the Photopolarimeter System (PPS) in 1991. This saved 1.2 watts of power.

Thruster Challenges

Some of the small thrusters that help control the spacecraft's direction are having problems. They are getting clogged. The spacecraft no longer has backup thrusters for this system. This means "everything onboard is running on single-string," as Suzanne Dodd, the Voyager project manager, explained. NASA developed a software update to help the remaining thrusters work better and slow down clogging. This update was first tested on Voyager 2 and then uploaded to Voyager 1.

The Future of Voyager 2

The probe is expected to keep sending weak radio messages until at least the mid-2020s. This means it will have been transmitting for more than 48 years since its launch. NASA says that "The Voyagers are destined—perhaps eternally—to wander the Milky Way."

Voyager 2 is not heading towards any specific star. The nearest star is 4.2 light-years away. At its speed of 15.341 kilometers per second (9.5 miles per second), it takes about 19,541 years to travel one light-year. In roughly 42,000 years, Voyager 2 is projected to pass the star Ross 248. This star is 10.30 light-years from Earth. If it remains undisturbed for 296,000 years, Voyager 2 is expected to pass by the star Sirius. Sirius is 8.6 light-years from Earth.

The Golden Record

Voyager Golden Record

Both Voyager space probes carry a special gold-plated record. It's like a time capsule from Earth. This record is a collection of sounds and images. It's meant to show the diversity of life and culture on Earth. The hope is that if any alien intelligence finds either spacecraft, they will learn about us.

A team led by Carl Sagan created the record. It includes photos of Earth and its living things. It also has scientific information. There are spoken greetings from people, including the Secretary-General of the United Nations. A medley called "Sounds of Earth" features sounds like whales, a baby crying, and ocean waves. There's also music from different cultures and times. This includes works by Wolfgang Amadeus Mozart, Blind Willie Johnson, Chuck Berry, and Valya Balkanska. The record also has greetings in 55 different languages. This project aimed to show the richness of life on Earth and humanity's desire to connect with the cosmos.

Images for kids

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  Voyager in transport to a solar thermal test chamber.

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  Voyager 2 awaiting payload entry into a Titan IIIE/Centaur rocket.

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  Neptune and Triton three days after Voyager 2 flyby.

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  Cirrus clouds imaged above gaseous Neptune.

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  Rings of Neptune taken from 280,000 km.

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  Voyager 2 color mosaic of Triton.

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  Voyager 2 view approaching Saturn.

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  North polar region of Saturn imaged in orange and UV filters.

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  Atmosphere of Titan imaged from 2.3 million km.

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  Titan passing in front of the Sun from 0.9 million km.

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  "Spoke" features observed in the rings of Saturn.

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  Departing image of crescent Uranus.

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  Ariel imaged from 130,000 km.

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  The rings of Uranus imaged by Voyager 2.

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  A transit of Io across Jupiter, July 9, 1979.

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  Several faint volcanic eruptions on Io, photographed by Voyager 2.

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  A color mosaic of Europa.

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  Voyager 2's path from Earth, heading south into the Pavo constellation after Neptune.

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  Path viewed from above the Solar System.

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  Path viewed from the side, showing distance below the ecliptic.

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  Voyager 2 launch on August 20, 1977.

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  Animation of Voyager 2's trajectory from 1977 to 2000.

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  Trajectory of Voyager 2 primary mission.

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  Voyager 2's speed against its distance from the Sun. This shows how gravity assists from planets sped it up.

See also

In Spanish: Voyager 2 para niños

• Family Portrait
• The Farthest, a 2017 documentary on the Voyager program.
• List of artificial objects leaving 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