Voyager 1

Voyager 1 is a space probe launched by NASA on September 5, 1977, as part of the Voyager program to study the outer Solar System and the interstellar space beyond the Sun's heliosphere. It was launched just 16 days after its companion, Voyager 2. As of March 2026, it is the farthest human-made object from Earth, traveling a distance of 172.59 AU, which is about 25.8 billion kilometers or 16 billion miles. By November 2026, it is expected to reach a distance of one light day from our planet.

During its journey, Voyager 1 flew by Jupiter, Saturn, and Saturn's largest moon, Titan. Scientists chose to study Titan because it has a thick atmosphere. The probe provided the first detailed images of these planets and their moons, showing their weather, magnetic fields, and rings.

In 2012, Voyager 1 made history by crossing the heliopause and entering interstellar space, becoming the first spacecraft to do so. It has continued to send valuable information back to Earth, even after experiencing solar storms known as coronal mass ejections.

In 2017, the team operating Voyager 1 used its trajectory correction thrusters for the first time in many years, which helped extend the mission. More thrusters were successfully revived in later years, including 2025. Although only two instruments still work, Voyager 1 is expected to keep sending data until around the year 2036, using its radioisotope thermoelectric generators.

Mission background

In the 1960s, NASA started planning a big trip to study the outer planets, called the Grand Tour. This led to the start of a mission in the early 1970s. Originally, Voyager 1 was named Mariner 11 as part of the Mariner program. But because of money problems, the mission was changed to just fly by Jupiter and Saturn, and it was renamed the Mariner Jupiter-Saturn probes. It was called Voyager when the probe designs became very different from the Mariner missions.

Voyager 1 was built by the Jet Propulsion Laboratory (JPL). It has a special shape like a ten-sided prism and many tools to keep it pointing toward Earth while it travels through space. It also carries 11 scientific tools to study planets and other objects in space.

Spacecraft components

Main article: Voyager program § Spacecraft design

Communication system

The radio communication system of Voyager 1 was made to work even far beyond the Solar System. It has a big round antenna to send and receive radio waves using special stations on Earth. Normally, it sends data to Earth using a special channel and frequency. When it cannot talk to Earth, it can record data to send later. As of 2025^[update], it takes more than 23 hours for its signals to reach Earth.

Power

Voyager 1 has three special power sources called radioisotope thermoelectric generators. They use a special kind of fuel and give off electricity. These power sources slowly lose power over time, but they are expected to keep working into the 2030s.

Computers

Unlike other tools on Voyager, the cameras are controlled by a special table inside one of the digital computers. This computer also helps with many important tasks, like pointing the antenna toward Earth. The system that controls how the spacecraft points is the same on both Voyager 1 and Voyager 2.

Scientific instruments

Main article: Voyager program

Mission profile

Timeline of travel

Launch and trajectory

The Voyager 1 probe was launched on September 5, 1977, from Launch Complex 41 at the Cape Canaveral Air Force Station, aboard a Titan IIIE launch vehicle. The Voyager 2 probe had been launched two weeks earlier, on August 20, 1977. Even though it was launched later, Voyager 1 reached both Jupiter and Saturn faster because it followed a shorter path.

Voyager 1's launch almost did not work because a part of the rocket shut down too early, leaving some fuel unused. The spacecraft's computers adjusted by extending the burn longer to give Voyager 1 the extra speed it needed.

At the end of the burn, the rocket was very close to running out of fuel. If the same problem had happened during Voyager 2's launch a few weeks earlier, the rocket would have run out of fuel before reaching the right path.

Flyby of Jupiter

Main article: Exploration of Jupiter

Voyager 1 began taking pictures of Jupiter in January 1979. Its closest approach to Jupiter was on March 5, 1979, at a distance of about 349,000 kilometers from the planet's center. Because of the closer distance, Voyager 1 could see details better than any previous spacecraft.

Voyager 1 discovered active volcanoes on the moon Io, the first time such activity was seen on another world. It also found two new moons of Jupiter: Metis and Thebe.

On February 25, 1979, Voyager 1 sent back the first detailed image of Jupiter's Great Red Spot.

Flyby of Saturn

Main article: Exploration of Saturn

Voyager 1 reached Saturn in November 1980, with its closest approach on November 12, 1980, at a distance of 124,000 kilometers from Saturn's clouds. It studied Saturn's rings, atmosphere, and its largest moon, Titan.

Voyager 1 found that Saturn's atmosphere has less helium than expected, which might explain why Saturn gives off more heat than it receives from the Sun. Winds on Saturn can blow at very high speeds.

The mission included a flyby of Titan, which has a thick atmosphere. The observations suggested that Titan might have lakes of liquid on its surface.

Exit from the heliosphere

On February 14, 1990, Voyager 1 took a picture of the whole Solar System from far away, including a famous image of Earth called the Pale Blue Dot. Soon after, its cameras were turned off to save power for other instruments.

In February 1998, Voyager 1 passed Pioneer 10 to become the farthest human-made object from Earth.

As Voyager 1 headed toward space beyond the Solar System, its instruments continued to study the Sun and its surroundings.

In 2012, Voyager 1 entered a new area where the Sun's influence weakens, and in 2013, it officially entered interstellar space, becoming the first human-made object to do so.

Interstellar medium

In March 2013, it was announced that Voyager 1 might have become the first spacecraft to enter interstellar space, having detected a marked change in the space environment on August 25, 2012. However, until September 12, 2013, it was still an open question as to whether the new region was interstellar space or an unknown region of the Solar System. At that time, the former alternative was officially confirmed.

In 2013, Voyager 1 was leaving the Solar System at a speed of about 3.6 AU per year, which is faster than Voyager 2. Each year, Voyager 1 increases its lead over Voyager 2.

Voyager 1 reached a distance of 135 AU from the Sun on May 18, 2016. On September 5, 2017, that had increased to about 139.64 AU from the Sun.

Its progress can be monitored at NASA's website.

Future of the probe

Remaining lifespan

In December 2017, NASA used new parts on Voyager 1 to keep its antenna pointing toward Earth. This helped the probe keep sending data to NASA for a few more years.

As the power on Voyager 1 gets weaker, the team has to choose which instruments to keep on and which to turn off. They focus on the instruments that give important information about space. In 2023, they thought Voyager 1 could keep working at least one instrument until around 2025. By late April 2026, two instruments were still working.

Concerns with the orientation thrusters

Some parts that help point Voyager 1 toward Earth stopped working because of problems with their hydrazine. NASA decided to change the spacecraft’s computer programs to slow down how fast these parts get blocked. They first tested this on Voyager 2 before trying it on Voyager 1.

In September 2024, NASA switched to different parts that had not been used since 2018. In May 2025, they fixed the backup parts used for spinning the spacecraft that had not worked since 2004.

Communication issues

In May 2022, Voyager 1 started sending unusual signals to the Deep Space Network. NASA found that a computer that had not worked for years was causing the problem. In August 2022, they told the spacecraft to use a different computer, and it started working again.

In November 2023, Voyager 1 began sending unreadable data. By December 2023, NASA found that a part of the spacecraft’s computer was not working well. By April 2024, they fixed the problem by moving the important programs to a different part of the computer. By May 2024, Voyager 1 was sending data from two of its instruments again, and by June 2024, all four instruments were working.

In October 2024, the spacecraft switched to a different radio system because of a problem with its main system. NASA was able to fix it and start getting data again in mid-November.

Between May 2025 and February 2026, the main antenna that talks to Voyager 1 and 2 was being updated, which made it harder to send commands to the spacecraft.

Far future

If nothing stops it, Voyager 1 is expected to reach a distant area of space called the Oort cloud in about 300 years and pass through it in about 30,000 years.

It is not going toward any specific star, but in about 40,000 years, it will pass close to a star named Gliese 445. In 300,000 years, it will pass close to another star called TYC 3135–52–1.

The New Horizons probe, even though it was launched faster, will never catch up to Voyager 1 because Voyager used gravity from planets to go faster. Voyager 1 is moving faster and will keep traveling through our galaxy.

Golden record

Main article: Voyager Golden Record

Both Voyager space probes carry a special gold-plated disc. This disc is meant to show the diversity of life and culture on Earth, just in case someone from far away ever finds the spacecraft.

The disc was made by a team that included famous scientists like Carl Sagan and Timothy Ferris. It has many things on it, such as pictures of Earth, sounds like whales singing, a baby crying, waves on the beach, and music from different cultures and times. Some of the music includes pieces by Wolfgang Amadeus Mozart, Blind Willie Johnson, Chuck Berry, and Valya Balkanska. There are also greetings in 55 different languages. The disc is a way to share what life on Earth is like and to show human creativity.