Voyager 2

Voyager 2 is a space probe launched by NASA on August 20, 1977, as part of the Voyager program. It was sent on a journey to explore the outer planets of our solar system. Voyager 2 became the only spacecraft to visit both the gas giants, Jupiter and Saturn, and the ice giants, Uranus and Neptune. Its mission was to study these distant worlds and learn more about space beyond our planet.

The spacecraft successfully flew by Jupiter in 1979, Saturn in 1981, Uranus in 1986, and Neptune in 1989. After completing these missions, Voyager 2 continued to travel farther away from the Sun. In November 2018, it became the second human-made object to enter interstellar space, the area beyond the Sun's heliosphere. This allowed scientists to make new discoveries about the conditions in the space between the stars.

Today, Voyager 2 is still sending information back to Earth from its journey through the interstellar medium. It is part of a special group of spacecraft that have traveled far enough to leave the Solar System. The probe stays in contact with scientists using special antennas, including one in Australia near Canberra. As it continues to move through space, Voyager 2 helps us understand the vast and mysterious regions far from home.

History

Further information: Grand Tour program

Background

Main article: Mariner Jupiter-Saturn

In the early days of space exploration, people noticed that the outer planets would line up in a special way in the late 1970s. This alignment meant one probe could visit Jupiter, Saturn, Uranus, and Neptune by using a technique called gravity assists. NASA started a big project called the Grand Tour, which planned to send two groups of probes to these planets. Later, the plan was simplified to just two probes that would fly by Jupiter and Saturn, but they could still go to Uranus and Neptune if needed.

Voyager 2 was designed to explore Jupiter and Saturn, and if everything went well, it could continue to Uranus and Neptune. This was possible because Voyager 1 had already completed its mission to Jupiter, Saturn, and Titan. The path for Voyager 2 was chosen to make the best use of this opportunity.

Spacecraft design

Voyager 2 was built by the Jet Propulsion Laboratory and had many tools to stay steady and point its antenna toward Earth. It carried 11 instruments to study the objects it passed by as it traveled through space.

Communications

Voyager 2 was made to eventually travel outside our solar system. It had a big antenna to send and receive data from Earth using the Deep Space Network. It could send information at different speeds depending on how far it was from Earth.

Power

Voyager 2 used special power sources called multihundred-watt radioisotope thermoelectric generators to keep its instruments running. These generators used a material called plutonium oxide to create electricity from heat. They were expected to keep working until at least 2020, and they continued to power some instruments until 2023. In 2024, one instrument was turned off to save power for the others.

Attitude control and propulsion

Voyager 2 had a special engine to help it get to Jupiter, and after that, it used smaller engines to stay steady and change its path if needed. It had enough fuel to keep working until about 2034.

Scientific instruments

Main article: Voyager program

Mission profile

The Voyager 2 probe was launched on August 20, 1977, by NASA from Cape Canaveral, Florida. It traveled to visit the gas giants Jupiter and Saturn, and then continued to the ice giants Uranus and Neptune. It remains the only spacecraft to have visited Uranus and Neptune.

Voyager 2 provided close-up images and important data about Jupiter, Saturn, Uranus, and Neptune, as well as their moons and rings. It showed active volcanoes on Jupiter's moon Io, discovered new moons around all four planets, and revealed details about the atmospheres and magnetic fields of these distant worlds.

Interstellar mission

After finishing its mission to the planets, Voyager 2 began an interstellar mission to explore what lies beyond the Solar System. As of September 2023, it continues to send scientific data from deep space, sharing what it discovers with scientists on Earth.

Voyager 2 has made many important observations. In 1992, it watched a star explosion called a nova and studied it in a way no other spacecraft had before. In 2007, it became the second human-made object to pass through the area where the Sun's influence ends, entering a region called the heliosheath. In 2018, it finally entered interstellar space, becoming the second spacecraft to do so. Despite facing some technical problems and temporary communication breaks, Voyager 2 keeps sending us valuable information about the far reaches of our Solar System and beyond.

Reductions in capabilities

As the power from the spacecraft's energy source slowly reduces, some equipment on Voyager 2 has been turned off. The first science tool to be turned off was the PPS in 1991, which saved a small amount of power.

Some tools that help aim the spacecraft and its antenna toward Earth are having problems because of clogged parts. NASA plans to adjust the computer programs to help the remaining tools work better. They will test this plan on Voyager 2 first because it is closer to Earth before trying it on Voyager 1.

Main article: Voyager 1

Future of the probe

The probe is expected to keep sending weak radio messages until at least the mid-2020s, more than 48 years after it was launched. NASA says that "The Voyagers are destined—perhaps eternally—to wander the Milky Way."

Voyager 2 is not headed toward any particular star. In about 42,000 years, it will pass the star Ross 248. Much later, in about 296,000 years, it should pass by the star Sirius.

Golden record

Main article: Voyager Golden Record

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

The disc was made by a team that included famous scientist Carl Sagan and writer Timothy Ferris. It has many things on it, like pictures of Earth, scientific facts, and greetings from important people such as the Secretary-General of the United Nations. It even includes sounds like whales, a baby crying, waves, and music from many different cultures and times — including pieces by Wolfgang Amadeus Mozart, Blind Willie Johnson, Chuck Berry, and Valya Balkanska. There are also greetings in 55 different languages, showing the rich and creative spirit of life on our planet.