NASA has shut down the plasma science instrument on Voyager 2 to save power. The remaining four instruments will continue gathering data in interstellar space. The mission has provided groundbreaking information about the outer planets and the heliosphere. Voyager 2, launched in 1977, is over 12.8 billion miles from Earth and still communicating. Both Voyager 1 and 2 have entered interstellar space, marking a historic achievement in space exploration.

Summary

• Voyager 2 launched in 1977 as part of NASA’s ambitious Grand Tour of the outer planets.
• Powered by plutonium-based RTGs, both Voyager spacecraft are slowly losing power.
• NASA decided to shut down the plasma science instrument on Voyager 2 to conserve energy for other tools.
• The remaining four instruments will continue to study the interstellar medium and outer heliosphere.
• Voyager 2 is over 20.5 billion kilometers away, moving at about 15 km/second.
• The twin Voyagers provided unprecedented images and data from Jupiter, Saturn, Uranus, and Neptune.
• The RTGs lose about 4 watts per year, and by the 2030s, most instruments will be offline.
• Voyager 2 entered interstellar space on November 5, 2018, following Voyager 1, which crossed in 2012.
• The plasma science instrument was key in detecting the heliopause, marking the boundary between our solar system and interstellar space.
• The Voyager missions remain NASA’s longest-running mission, providing invaluable data about the outer planets and beyond.

NASA’s Decision to Shut Down Voyager 2’s Plasma Science Instrument

NASA’s decision to power down the plasma science instrument on Voyager 2 marks a vital moment in the spacecraft’s remarkable 47-year mission. As the spacecraft continues its journey through interstellar space, it faces an ever-decreasing power supply from its radioisotope thermoelectric generators (RTGs). Shutting down the plasma science instrument ensures that Voyager 2’s other critical tools can continue to function for as long as possible.

The plasma science instrument played a crucial role in measuring ionized particles and determining the spacecraft’s transition into interstellar space. However, its limited utility in recent years, due to the orientation of Voyager 2 relative to the plasma flow in space, made it the most logical choice for deactivation. This action reflects NASA’s ongoing efforts to manage Voyager 2’s power supply and maintain the mission’s scientific output.

Voyager 2’s remaining instruments will continue gathering data, offering scientists a wealth of information about the outer heliosphere and the interstellar medium. These tools include a magnetometer, a charged particle instrument, a cosmic ray system, and a plasma wave detector. Each of these instruments provides unique insights into the space environment outside our solar system, helping researchers understand phenomena such as the interstellar magnetic field and cosmic rays.

Voyager 2’s journey began in 1977, when it was launched as part of NASA’s Grand Tour of the outer planets. The spacecraft was designed to take advantage of a rare planetary alignment, which occurs only once every 175 years, allowing it to visit Jupiter, Saturn, Uranus, and Neptune. The mission’s goal was to study these planets and their moons in detail, providing the first-ever close-up views of the outer solar system.

During its flybys, Voyager 2 made numerous groundbreaking discoveries, including active volcanoes on Jupiter’s moon Io, the intricate ring system of Saturn, and the mysterious atmosphere of Neptune. Voyager 2 remains the only spacecraft to have visited Uranus and Neptune, revealing surprising details about these distant planets and their moons.

After completing its planetary tour, Voyager 2 entered the Voyager Interstellar Mission (VIM) phase. This mission aimed to study the boundaries of our solar system, known as the heliosphere, and the space beyond. In 2018, Voyager 2 became the second spacecraft to leave the heliosphere and enter interstellar space, following Voyager 1’s milestone in 2012.

The plasma science instrument played a crucial role in detecting the heliopause, the boundary where the Sun’s influence ends, and interstellar space begins. As Voyager 2 crossed this threshold, the instrument measured a dramatic decrease in solar wind particles and an increase in cosmic rays from outside the solar system.

Table 1: Voyager 2’s Journey Milestones

Both Voyager spacecraft are powered by radioisotope thermoelectric generators (RTGs), which convert heat from decaying plutonium-238 into electricity. At the time of launch, each RTG provided 157 watts of electrical power, enough to keep Voyager 2 operational. However, the power output halves every 87.7 years, meaning the spacecraft’s available energy is steadily declining. NASA estimates that Voyager 2 loses about 4 watts of power each year, limiting its ability to run all onboard systems.

As power continues to dwindle, NASA engineers have been forced to make tough decisions about which instruments to prioritize. Over the past few years, they have turned off various non-essential systems, including heaters and voltage monitors, to conserve power for science instruments. The shutdown of the plasma science instrument is part of this broader effort to extend Voyager 2’s mission for as long as possible.

The Voyager mission is one of the most iconic in NASA’s history. Launched over 45 years ago, the twin spacecraft have traveled farther from Earth than any other human-made objects. Their discoveries have reshaped our understanding of the solar system, and their ongoing exploration of interstellar space continues to provide insights into a region of the universe that has never been studied before.

While Voyager 2 still has four operational instruments, its mission is entering its final phase. By the 2030s, the spacecraft will likely be down to just one or two working tools. However, even as its power supply diminishes, Voyager 2 will continue its journey through the cosmos, offering a unique glimpse into the mysteries of interstellar space.

NASA is already preparing for the inevitable end of the Voyager mission. When Voyager 2’s power finally runs out, the spacecraft will become a silent ambassador of Earth, carrying a golden record filled with sounds and images representing life on our planet. This record is intended to communicate with any intelligent beings that might encounter Voyager 2 in the distant future.

Voyager 2’s Scientific Contributions

Despite its aging systems, Voyager 2 remains an invaluable asset to space science. The data it continues to send back helps scientists understand phenomena such as the behavior of the interstellar medium and the interaction between the heliosphere and interstellar space. As the spacecraft travels farther from the Sun, its instruments provide a rare opportunity to study a region of space that has never been explored before.

Table 2: Voyager 2’s Operational Instruments

The shutdown of Voyager 2’s plasma science instrument is a reminder that even the most ambitious space missions must eventually come to an end. Yet, despite this, Voyager 2 continues to push the boundaries of human exploration, sending back data from a region of space that no other spacecraft has reached. As it journeys farther into the unknown, Voyager 2 remains a testament to human curiosity, determination, and the enduring quest to understand our place in the universe.

References

• NASA Voyager 2: A Journey Through Space
• The Voyager Mission: 40 Years of Exploration
• The Science Behind Voyager: How It Works 5. Voyager: The Interstellar Mission

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