Expecting the unexpected on Saturn’s moons
In exploring deep space, as in life, planning only allows you now. Preparation is essential, but you should be prepared to improvise when you encounter surprises – such as a constantly erupting world of ice volcanoes, or a system of rivers and lakes based on liquid methane or giant plastic dunes.
The dunes and methane lakes on Titan and Enceladus ice volcanoes – the two giant giant Saturn moons and part of the border that NASA explores its epic mission Cassini. Cassini scientists had to think several times during the nearly 20-year effort, which will end in the fall, when the spacecraft will be depleted of fuel.
“We had to change plans … to make observations, we were not sure what we wanted to do until we saw some things we did not expect to see,” said Jeffrey Moore, planetary scientist NASA Ames Research Center in California. And 900 million kilometers from your home, you can not exactly go back to get a different camera.
In the early 1980s, NASA’s twin Voyager spacecraft flew and photographed Saturn and its larger moons, but these are brief encounters with mid-twentieth-century technology. They gave advice on a Cassini mission supported as he could observe, Moore said.
So Cassini was built with flexibility. He was bristling with instruments, he said, “like a Swiss army knife flying.” You may begin to think that the blade, screws or scissors are for one thing, but once you are out hiking, they realize that they could be used for something else.
In Cassini, he said, instruments designed to study the particles trapped in Saturn’s magnetic field were revised to measure the composition of the material that was cast in active Enceladus volcanoes.
This revealed something important. Enceladus receives fine sunlight, but gets the internal energy from the friction generated by the movement of massive tides. Thus, while the crust of Enceladus is frozen, this internal heat heats an ocean of liquid water beneath. Measurements of Cassini showed that the water broke in ice volcanoes was mixed with the material from the rocky interior of the moon: organic and inorganic. With Cassini, Enceladus now joins the moon Europa of Jupiter as still possible that extraterrestrial life.
Titan’s overflights, Saturn’s largest moon, revealed something astounding. This is the only other body in the solar system with the characteristics of the earth’s surface: lakes, seas, rivers, rain, wind and sand dunes.
“Titan is an explorer of utopia,” said Alex Hayes, a planetary scientist at Cornell University. People can see Titan from terrestrial telescopes, he said, and in the 20th century, astronomers have seen characteristics attributed to a refined environment. Pioneer and Voyager 2 flew by Titan and took photos, which revealed a sphere of orange haze.
But what was beneath? This was tedious, Hayes said, because remote sensing techniques have shown that the atmosphere contained a lot of methane, and the temperature and pressure predicted on Titan, methane must work much as water does on Earth – existing in liquid, solid and soda. “There could be a complete analogy with the way water works on earth,” he said.