Cassini - Diving Between Saturn and the Rings

Updated on April 27 - see below. 

Today, April 26, the Cassini spacecraft passed between Saturn and its rings for the first time ever. This is a first - no spacecraft has ever explored the space between a planet and its rings before - it could be risky business! 

This artist's rendering shows NASA's Cassini spacecraft above Saturn's northern hemisphere, heading toward its first dive between Saturn and its rings on April 26, 2017. Credit: NASA/JPL-Caltech

As explained in this previous post, the Cassini spacecraft is running out of fuel. When it is out of fuel, it won't be able to steer, and could be a danger to Saturn's moons that have important habitats, such as Encleadus and Titan. In order to protect the moons, mission planners will deliberately send Cassini into Saturn's atmosphere on September 15. The heat and pressure will destroy it, ending the mission. 

Because the mission is ending, the engineers are getting closer to the ring plane then ever before. Some fantastic images have been released of Saturn's ring particles, such as this one:

These ring gaps get me every time. Image Credit

 Just last week, a new image of Earth from Saturn was released. It is beautiful. 

That's us. That's here. That's home. Image Credit

Cassini should have passed through the gap between Saturn and the rings once already, and is scheduled to do so again this evening. Because no spacecraft has done this before, Cassini will use its large high-gain antenna as a shield while passing through the ring plane. Mission planners are not exactly sure where the ring starts, so while no large particles are expected, the engineers are being cautious. Cassini will be traveling at a blistering 21 miles per second, so hitting something larger than a smoke particle could damage the spacecraft. NASA will be measuring the size and density of the ring particles in the gap to plan for future dives. 

The spacecraft is currently out of contact, because it is using its antenna as a shield. We are expecting it to reestablish communication in the wee hours of morning on April 27. There should be raw images released to the public by 2:30 am on April 27, or when you wake up on Thursday morning! 

Check out this animation showing Cassini's final orbits.

You can check Cassini's JPL page for updates and raw images. Also follow it on Facebook, to get the latest news and updates as they happen!

Recent image of Saturn from Cassini. Image Credit

Update from April 27: Cassini was Successful!
Cassini successfully made two passes in the gap between Saturn and the rings, and is in great shape. This means mission planners will not have to be quite so cautious for the next 20 passes through the gap, and can keep the antenna pointed toward Earth. The first raw images were released. Soon many more images will be released, and when they are processed I bet they will be stunning. 

These unprocessed images show features in Saturn's atmosphere from closer than ever before. The view was captured by NASA's Cassini spacecraft during its first Grand Finale dive past the planet on April 26, 2017. Credit: NASA/JPL-Caltech/Space Science Institute

Cassini got the closest to Saturn it ever has with these passes, and will just keep getting closer as the months pass.Cassini came within about 1,900 miles of Saturn's cloud tops (where the air pressure is comparable to the atmospheric pressure of Earth at sea level) and within about 200 miles of the innermost visible edge of the rings.

Oh, I will miss this mission and the beautiful images it has sent back over the years. Follow along with us at the Dome Planetarium as the mission ends - we'll have a special show this summer showing off some of the greatest images from past years and the latest close ups. Remember, you can always learn what's up in the night sky in the Dome Planetarium at the Peoria Riverfront Museum, where we teach about space and science everyday. Follow us on Facebook or Twitter for daily updates!