Tag: Saturn

Cassini Inside the Rings of Saturn

 

Movie produced from images taken while Cassini flew inside the rings of Saturn – a first. (NASA/JPL-Caltech/Space Science Institute)

The triumphant Cassini mission to Saturn will be coming to an end on September 15, when the spacecraft dives into the planet.  Running out of fuel, NASA chose to end the mission that way rather than run the risk of having the vehicle wander and ultimately land on Europa or Enceladus, potentially contaminating two moons very high on the list of possible habitable locales in our solar system.

Both the science and the images coming back from this descent are (and will be) pioneering, as they bring to an end one of the most successful and revelatory missions in NASA history.

As NASA promised, the 22-dive descent has already produced some of the most compelling images of Saturn and its rings.  Most especially, Cassini has delivered the remarkable 21-image video above.  The images were taken over a four minutes period on August 20 using a wide-angle camera.

The spacecraft captured the images from within the gap between the planet and its rings, looking outward as the spacecraft made one of its final dives through the ring-planet gap as part of the finale.

The entirety of the main rings can be seen here, but due to the low viewing angle, the rings appear extremely foreshortened. The perspective shifts from the sunlit side of the rings to the unlit side, where sunlight filters through.

On the sunlit side, the grayish C ring looks larger in the foreground because it is closer; beyond it is the bright B ring and slightly less-bright A ring, with the Cassini Division between them. The F ring is also fairly easy to make out.

 

NASA’s Cassini spacecraft will make 22 orbits of Saturn during its Grand Finale, exploring a totally new region between the planet and its rings. NASA/JPL-Caltech

While the Cassini team has to keep clear of the rings, the spacecraft is expected to get close enough to most likely answer one of the most long-debated questions about Saturn: how old are those grand features, unique in our solar system?

One school of thought says they date from the earliest formation of the planet, some 4.6 billion years ago. In other words, they’ve been there as long as the planet has been there.

But another school says they are a potentially much newer addition. They could potentially be the result of the break-up of a moon (of which Saturn has 53-plus) or a comet, or perhaps of several moons at different times.… Read more

What Scientists Expect to Learn From Cassini’s Upcoming Plunge Into Saturn

Saturn as imaged from above by Cassini last year. Over the next five months, the spacecraft will orbit closer and closer to the planet and will finally plunge into its atmosphere. (NASA)

Seldom has the planned end of a NASA mission brought so much expectation and scientific high drama.

The Cassini mission to Saturn has already been a huge success, sending back iconic images and breakthrough science of the planet and its system.  Included in the haul have been the discovery of plumes of water vapor spurting from the moon Encedalus and the detection of liquid methane seas on Titan.  But as members of the Cassini science team tell it, the end of the 13-year mission at Saturn may well be its most scientifically productive time.

Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory (JPL) put it this way: “Cassini will make some of its most extraordinary observations at the end of its long life.”

This news was first announced last week, but I thought it would be useful to go back to the story to learn more about what “extraordinary” science might be coming our way, with the help of Spilker and NASA headquarters Cassini program scientist Curt Niebur.

And the very up close encounters with Saturn’s rings and its upper atmosphere — where Cassini is expected to ultimately lose contact with Earth — certainly do offer a trove of scientific riches about the basic composition and workings of the planet, as well as the long-debated age and origin of the rings.  What’s more, everything we learn about Saturn will have implications for, and offer insights into, the vast menagerie of  gas giant exoplanets out there.

“The science potential here is just huge,” Niebur told me.  “I could easily conceive of a billion dollar mission for the science we’ll get from the grand finale alone.”

 

The Cassini spacecraft will make 22 increasingly tight orbits of Saturn before it disappears into the planet’s atmosphere in mid-September, as shown in this artist rendering.  (NASA/JPL-Caltech)

 

The 20-year, $3.26 billion Cassini mission, a collaboration of NASA, the European Space Agency and the Italian Space Agency,  is coming to an end because the spacecraft will soon run out of fuel.  The agency could have just waited for that moment and let the spacecraft drift off into space, but decided instead on the taking the big plunge.

This was considered a better choice not only because of those expected scientific returns, but also because letting the dead spacecraft drift meant that theoretically it could be pulled towards Titan or Enceladus — moons that researchers now believe just might support life.… Read more

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