Voyager 2 Lost the Plasma Science Instrument To Survive – Where Is the Probe Now?

NASA scientists had to sacrifice the plasma science instrument aboard Voyager 2 to save the spacecraft. The probe’s electrical power supply is gradually shrinking, but four science instruments are still operational.

Voyager 2 Loses Plasma Science Instrument

On 26 September, NASA engineers turned off Voyager 2 plasma science. The command was sent through NASA’s Deep Space Network and took 19 hours to reach the spacecraft, and then it took another 19 hours for Voyager 2’s response to get back to Earth.

The mission team always watches closely when making changes to the 47-year-old spacecraft to make sure nothing goes wrong. They confirmed that the tool was turned off successfully, and the spacecraft still works fine.

In 2018, the PLS was critical in determining that Voyager 2 had left the heliosphere – but power management is a major challenge when you’ve been exploring for 47 years. The edge of the heliosphere, where it meets interstellar space, is marked by changes in atoms, particles, and magnetic fields that the Voyager probes can detect. Inside the heliosphere, particles from the Sun flow outward, but as the heliosphere moves through space, at Voyager 2’s position, the plasma flows in the opposite direction of the Sun’s particles.

The plasma science instrument has four “cups.” Three face the Sun and measured the solar wind while Voyager 2 was inside the heliosphere. The fourth cup points sideways and has detected plasma in planetary magnetic fields, the heliosphere, and now in interstellar space.

When Voyager 2 left the heliosphere, the plasma flowing into the three Sun-facing cups dropped suddenly. The fourth cup collects useful data only once every three months when the spacecraft spins in a full circle. Because of this limited data, the team decided to turn off this instrument before others.

Voyager 2 is a scientific rockstar

Voyager 2 was launched in 1977 and it’s now 12.8 billion miles (20.5 billion kilometers) away from home. The spacecraft was aimed to learn more about the outer planets of the Solar System. Besides that, similar to Voyager 1, Voyager 2 carries a “Golden Record” with sounds, images, and greetings from Earth, intended to communicate with potential extraterrestrial civilizations.

The probe carries four scientific instruments to explore the area outside our heliosphere, which is a shield of particles and magnetic fields made by the Sun. Due to the distance from Earth and years of operations, the probe is slowly loosing power. Still, Voyager 2 has enough power to continue exploring this region with at least one operational science instrument into the 2030s.

Voyagers are especially valuable for scientists as they are the only spacecraft which have travelled so far. No other human-made object has operated in interstellar space.

As Voyager 2 crossed into interstellar space in 2018, it provided direct measurements of the environment outside the Sun’s influence, something no other mission had done before. This data helps scientists understand how the Sun’s protective bubble interacts with the interstellar medium and gives us insight into cosmic rays, magnetic fields, and particle behavior in deep space. Since Voyager 2 also explored all the outer planets (Jupiter, Saturn, Uranus, and Neptune), its journey and observations offer a one-of-a-kind view of our solar system and beyond.

Both spacecraft are powered by decaying plutonium and lose about 4 watts of power each year.