Voyager, NASA’s longest mission, spends 45 years in space

Launched in 1977, the Voyager twin probes are NASA’s longest-running mission and the only spacecraft to ever explore interstellar space.

NASA’s Voyager twin probes have become, in some ways, time capsules of their time: they each carry an eight-track tape drive to record data, they have about 3 million times less memory than cell phones and they transmit data about 38,000 times slower. than a 5G internet connection.

Yet the Voyagers remain at the forefront of space exploration. Managed and operated by NASA’s Jet Propulsion Laboratory in Southern California, they are the only probes to have ever explored interstellar space – the galactic ocean through which our Sun and its planets pass.

The Sun and the planets reside in the heliosphere, a protective bubble created by the Sun’s magnetic field and the outward flow of solar wind (charged particles from the Sun). Researchers – some of whom are younger than the two distant spacecraft – combine Voyager observations with data from more recent missions to get a more complete picture of our Sun and how the heliosphere interacts with interstellar space. .

“The Heliophysics Mission Fleet provides invaluable information about our Sun, from understanding the corona or outermost part of the Sun’s atmosphere, to examining the Sun’s impacts throughout the Solar System, including including here on Earth, in our atmosphere and in interstellar space,” said Nicola Fox, director of the Heliophysics Division at NASA Headquarters in Washington. “Over the past 45 years, Voyager missions have played a essential in providing this knowledge and have helped change our understanding of the Sun and its influence like no other spacecraft can.”

The Voyagers are also ambassadors, each carrying a gold disc containing images of life on Earth, diagrams of basic scientific principles, and sound including sounds of nature, greetings in multiple languages, and music. The gold-coated discs serve as a cosmic “message in a bottle” for anyone who might encounter the space probes. At the rate gold decays in space and is eroded by cosmic radiation, the records will last for over a billion years.

beyond all expectation

Voyager 2 was launched on August 20, 1977, quickly followed by Voyager 1 on September 5. Both probes traveled to Jupiter and Saturn, with Voyager 1 moving faster and reaching them first. Together, the probes revealed a lot about the two largest planets in the solar system and their moons. Voyager 2 also became the first and only spacecraft to fly near Uranus (in 1986) and Neptune (in 1989), giving humanity remarkable views and glimpses of these distant worlds.

While Voyager 2 was making these flybys, Voyager 1 was heading towards the edge of the heliosphere. When it was released in 2012, Voyager 1 discovered that the heliosphere blocks 70% of cosmic rays, or energetic particles created by exploding stars. Voyager 2, having completed its planetary explorations, continued to the edge of the heliosphere, exiting in 2018. Combined data from the sister spacecraft in this region has challenged previous theories about the exact shape of the heliosphere.

“Today, as the two Voyagers explore interstellar space, they provide humanity with observations of uncharted territories,” said Linda Spilker, Voyager Project Assistant Scientist at JPL. “This is the first time we have been able to directly study how a star, our Sun, interacts with particles and magnetic fields outside our heliosphere, helping scientists understand the local neighborhood between stars, reversing some theories about this region, and provide key information for future missions.

Voyager 1 and 2 have accomplished a lot since their launch in 1977. This infographic highlights the main milestones of the mission, including visiting the four outer planets and exiting the heliosphere, or the protective bubble of magnetic fields and particles created by the Sun.

The long journey

Over the years, the Voyager team has grown accustomed to overcoming the challenges of operating such mature spacecraft, sometimes calling on retired colleagues for their expertise or digging into documents written decades ago. .

Each Voyager is powered by a radioisotope thermoelectric generator containing plutonium, which gives off heat which is converted into electricity. As the plutonium decays, the heat output decreases and the Voyagers lose electricity. To compensate, the team shut down all non-essential systems and some once considered essential, including the heaters that protect still-operating instruments from the freezing temperatures of space. The five instruments whose heaters have been turned off since 2019 are still working, despite being well below the lowest temperatures at which they have ever been tested.

Recently, Voyager 1 began to experience an issue that was causing status information to be confused on one of its onboard systems. Despite this, the system and the spacecraft continue to function normally, suggesting that the problem lies with the production of the status data, and not with the system itself. The probe is still sending back scientific observations while the engineering team tries to solve the problem or find a way around it.

“Voyagers have continued to make incredible discoveries, inspiring a new generation of scientists and engineers,” said Suzanne Dodd, Voyager project manager at JPL. “We don’t know how long the mission will continue, but we can be sure the spacecraft will provide even more scientific surprises as it gets further away from Earth.”

Learn more about the mission

A division of Caltech in Pasadena, JPL built and operates the Voyager spacecraft. The Voyager missions are part of NASA’s Heliophysical System Observatory, sponsored by the Heliophysics Division of the Science Mission Directorate in Washington.

For more information on the Voyager spacecraft, visit

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