In 1977, NASA took advantage of a once-in-a-lifetime alignment of the planets to send two probes to the outermost reaches of the solar system.

They sent back the best images and data available at that time about Jupiter, Saturn, Uranus, and Neptune.

The program was a smashing success.

However, the probes never stopped traveling.

They kept going and going all the while maintaining contact with Earth. They ended up teaching us far more about the solar system than we

ever expected. Learn more about the never-ending Voyager program and how spacecraft, a half-century

old, are still performing valuable science on this episode

of Everything Everywhere Daily.

The Voyager 1 and 2 missions have been mentioned in several previous episodes of the podcast.

They were first mentioned in the episode on the Golden Record, which was attached to each spacecraft to teach anyone who might find it centuries or thousands of years from now about our world.

Likewise, there were episodes on Jupiter, Saturn, Uranus, and Neptune, as well as the Kuiper Belt, which also featured the Voyager missions. As the missions were planned, both

Voyagers 1 and 2 were considered a success. Voyager 1 made a flyby of Jupiter's Saturn and Saturn's largest

moon Titan. Voyager 2 also did a fly by of Jupiter and Saturn and became the first probe

ever to fly by Uranus and Neptune. After Voyager 1's flyby of Saturn in November of 1990,

the mission objectives had all been completed. It moved into what was called

its interstellar mission. Many of the team members who had been assembled for the program

ended up moving on to other things. However, while the primary mission objectives were

technically over, the spacecraft were not. While each Voyager probe was sent on a different

trajectory, they were each still on the courses set by their gravitational slingshots.

Moreover, each of the spacecraft had enough power to last for decades, albeit at varying capacities.

So the first part in understanding how it is even possible for these probes to still be operating

is understanding their power sources, radioisotope, thermoelectric generators, or RTGs.

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