August 25, 1981. Voyager 2 makes its closest approach to Saturn. The data and images gathered from this close encounter kickstarted talks between U.S. and Europe about another mission to the ringed world just one year later. The mission’s name? Cassini.
“Saturn, like all of the planets the Voyagers visited, was full of exciting discoveries and surprises,” said Ed Stone, Voyager project scientist at Caltech in Pasadena, California. “By giving us unprecedented views of the Saturn system, Voyager gave us plenty of reasons to go back for a closer look.”
Here’s just a taste of the “unprecedented views” Voyager 2 gave the world.
Voyager 2 was still more than 13 million kilometers away when it captured the image above. See the ‘ribbonlike’ feature in the white cloud band? It’s a high-speed jet with westerly winds whipping at 330 miles per hour.
The majestic rings of Saturn never fail to impress. But the moons of Saturn have no problem stealing some of the spotlight. Voyager flybys of the Saturn system revealed a collection of unique moons. This image of Titan teased the structure and composition of its atmosphere.
The Voyager missions saw Titan as nothing more than a hazy ball. What lied beneath this hazy atmosphere? That was one of the primary goals of the Cassini mission. Armed with infrared cameras, Cassini revealed a stunning world with methane lakes and flooded canyons.
Enceladus gave scientists much to think about after Voyager 2 hinted the moon might be active. You can see craters give way to a much smoother surface. The image below told scientists the smoother parts of Enceladus were much younger, geologically speaking. That hint would become fact when the Cassini mission arrived in 2004.
Today, the Voyager missions sit at least 111 AU (distance between Earth and Sun = 1 AU) from Earth. Voyager 1 is 135.7 AU (20.3 billion kilometers) away. Voyager 2 is right behind it at 111.4 AU (16.6 billion kilometers).
Did You Know: Sometimes the distance counters on Voyager’s website roll backward. Nope, it’s not an error. Earth moves faster around the sun than either Voyager spacecraft is leaving from Earth.
As part of the Heliophysics System Observatory, Voyager explores a region called the interstellar boundary region. Here, material blowing outward from the sun hits similar winds from other stars.
As for Cassini? It’s still revealing tantalizing new features in the Saturn system. Recently, the spacecraft’s radar instruments probed the deep canyons of Titan and found the first direct evidence of liquid-filled canyons.
Earlier this week, a new image of Dione was released. It was captured last year and shows the contrast between the moon’s tectonic features (seen as bright lines) and the older craters.
On September 26, Cassini will conduct another close flyby of Titan. It will be just 1,079 miles above the moon’s surface. It will continue conducting close and distant flybys of Saturn’s moons until the mission’s ‘Grand Finale.’
Starting at the end of November, Cassini will climb above Saturn’s north pole before plunging just outside the main rings. The real fun begins on April 22. Cassini will jump over the rings and begin a series of orbits taking it between the planet and the inner edge of the rings.
The images from these orbits will be breathtaking. Plus, Cassini’s particle detectors should be able to sample icy ring particles and learn more about their origins.
We’ve learned so much about the Saturn system in the last 35 years. And there’s still so much more to learn.