The two Voyager probes have left the solar system and are still collecting data from the interstellar environment. However, their atomic hearts are growing weaker and weaker due to nuclear battery depletion. NASA is preparing for the end of the mission in the next decade.
Introduction
The Voyager probes, launched between August and September 1977, are the oldest and most distant probes built that are still active. They have left the solar system and are collecting data from the interstellar environment.
History of the Voyagers
The Voyagers began as planetary missions with a goal to carry out the so-called Planetary Grand Tour: visiting the four outer planets through flyovers. Jupiter, Saturn, Uranus, and Neptune were studied using robotic cameras and scientific instruments.
Leaving the Solar System
After completing their planetary journeys, both probes reached escape velocity for the solar system, allowing them to be released from the sun’s gravity. Since 2012 for Voyager 1 and 2018 for Voyager 2, they have become interstellar.
The Secret to a Long Life
The secret to their long life lies in their atomic hearts: three radioisotope thermoelectric generators (RTGs) equipped with plutonium-238 oxide spheres. These RTGs produce power directly on board by converting the heat generated from radioactive decay into electricity.
Depletion of Energy Sources
As time passes, the plutonium on board is depleted, and so the RTGs produce less and less energy. The Voyagers are therefore slowly dying. Nuclear batteries have a maximum lifespan of 60 years.
Conservation of Remaining Energy
The mission team is gradually shutting down various instruments to conserve the remaining energy. Four active instruments remain, including a magnetometer used to study the galactic environment.
Conclusion
In the next decade, it’s hard to say exactly when, the batteries of both probes will be drained forever.
References
This story originally appeared on WIRED Italia and has been translated from Italian.
Key Facts
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The Voyager probes were launched between August and September 1977.
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They have left the solar system and are collecting data from the interstellar environment.
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Nuclear batteries have a maximum lifespan of 60 years.
The two probes have left the solar system and are still collecting data from the interstellar environment—but their atomic hearts are growing weaker and weaker. NASA/JPL-Caltech
Reaching such a distance is only possible with the right energy source. Many probes use solar panels, but if they move too far from the sun, they become useless (the farthest probe that uses them is the Juno probe orbiting Jupiter). The secret of the Voyagers lies in their atomic hearts: both are equipped with three radioisotope thermoelectric generators.
Nuclear Power
The End of the Mission
Remaining Instruments
Four active instruments remain, including a magnetometer as well as other instruments used to study the galactic environment, with its cosmic rays and interstellar magnetic field. But these are in their last years. In the next decade—it’s hard to say exactly when—the batteries of both probes will be drained forever.
Legacy of the Voyager Probes
Jupiter and its Great Red Spot. NASA/Voyager The icy giants Uranus and Neptune, in particular, were studied for the first and only time in history by Voyager 2, while successful observations of Jupiter and Saturn were the basis for subsequent interplanetary missions to these worlds, such as Galileo, Juno, and Cassini-Huygens.
- wired.com | The End Is Near for NASA’s Voyager Probes
- reddit.com | The End Is Near for NASAs Voyager Probes : r/space
