Cassini: Farewell to Saturn

[Crispy]

Starting later this month, Cassini, low on fuel, will make a series of ever-closer orbits of Saturn, between the planet and its rings, until finally entering its atmosphere in September. Here's a spectacular video from Erik Wernquist, who made that Wanderers short film:



(he did one for New Horizons too)

The spacecraft will do its best to transmit right to the very end, giving us the closest ever look at the atmosphere and clouds of Saturn.

 

[EastEnder]

I can't believe it's been TWENTY years since Cassini launched!

Think I might shed a tear when it finally ends....

 

[Crispy]

Hell, I shed a tear at the end of this video!

 

[MikeMcc]

Still no word on regaining comms after the first fly-through...

ETA: Just been reading up on the manoeuvre. We're not expecting anything back from it until 0805 Thu 27th.

As Cassini Makes 1st 'Grand Finale' Dive, More Saturn Mysteries Remain

 

[editor]

Still no word on regaining comms after the first fly-through...

Isn't that scheduled for 8am tomorrow?

 

[2hats]

Carrier signal lock and data flowing; so all well, it survived.

 

[editor]

These unprocessed images show features in Saturn's atmosphere from closer than ever before

Cassini: Mission to Saturn: NASA Spacecraft Dives Between Saturn and Its Rings

 

[T & P]

Will there be (or indeed, have there ever been) any close up images taken of the rings? Perhaps edge-on? I'm thinking this kind of artist's impression...

 

[2hats]

Not until guided (probably AI driven) probes are flown (or fly themselves) there which can autonomously and interactively navigate within the rings. No (purely) orbiting spacecraft could risk positioning to take such images. Even co-orbiting with the ring material would be risky. Navigating like that would be expensive in energy terms too.

Cassini has taken some nice images which hint at the weird and wonderful gravitational ballet the individual ring building blocks play with each other and local satellites of Saturn (eg below), but that ring material isn’t itself resolved.

This is the case even in the ‘highest resolution’ images taken of the rings in recent months (note bright pixels and streaks in this image are noise in the detector due to cosmic ray hits and the local radiation environment):

 

[editor]

Look at these!

These are the first real-color images of Saturn’s polar vortex - DIY Photography

 

[Jonti]

Not long now till Cassini's end. It's due to burn up in Saturn's atmosphere on 15th September. Nature magazine has a look at some of what's been achieved: Cassini’s 13 years of stunning Saturn science — in pictures

 

[HAL9000]

Cassini hints at young age for Saturn's rings

"So, we're heading in the direction of the rings being perhaps 100 million years old or so, which is quite young compared to the age of the Solar System," she told BBC News.

Dr Spilker did however caution that these were early days in the analysis of the new data and the uncertainties were still large.

Cassini hints at young age for Saturn's rings - BBC News

 

[mather]

Look at these!

These are the first real-color images of Saturn’s polar vortex - DIY Photography

Why is it azure on colour?

Is it made from the same gas Neptune?

 

[NoXion]

Why is it azure on colour?

Is it made from the same gas Neptune?

The atmosphere in those locations scatters blue light, much like a clear sky does on Earth.

However, given that Saturn is a gas giant, the cause of the blue colour is more likely to be caused by the presence of methane, like on Neptune, rather than nitrogen and oxygen.

 

[Jonti]

It's the rings of Saturn, Jim, but not as we've known them:



This view from NASA's Cassini spacecraft shows a wave structure in Saturn's rings known as the Janus 2:1 spiral density wave. More from NASA ...

 

[Steel Icarus]

Astounding image - and explanation.

 

[Jonti]

Just a beautiful picture really, showing Saturn's polar aurora imaged in UV light:

 

[2hats]

Titan slingshot maneuver completed as planned late last night. Now set up for atmospheric entry on Friday.

 

[2hats]

As Cassini enters its final hours, NASA has released a free ebook documenting some of the most fascinating/beautiful/revalatory images from the entire mission.

Over a period of 13 years, Cassini has captured about 450,000 spectacular images within the Saturn system, providing new views of the “lord of the rings” and a plethora of iconic images. To honor the art and science of Cassini, this book was developed collaboratively by a team from NASA’s Planetary Science Division (PSD), NASA’s Jet Propulsion Laboratory (JPL), and the Lunar and Planetary Institute (LPI). While these images represent the tip of the iceberg—each telling a story about Saturn and its mysterious moons—our hope is that the mission will inspire future artists and explorers. The sheer beauty of these images is surpassed only by the science and discoveries they represent.

 

[2hats]

Timeline for the final plunge coming up, expected around 1254BST tomorrow (times indicated are Earth received time in PDT, so add 8 hours for BST):

 

[petee]

says here that NASA will broadcast the end of cassini at 7 am eastern Friday

Cassini’s Final Moments and Plunge Into Saturn: What to Expect

 

[editor]

I'll shed a tear for this wonderful piece of technology.

 

[Crispy]

mmm, this is nice

 

[2hats]

Recorded data playback is coming to an end and Cassini will switch to real-time data transmission shortly (and for the last time). Spacecraft rolled to allow the INMS (Ion and Neutral Mass Spectrometer) to sample the planet’s atmosphere all the way down. About 171,000km left to go.

 

[wayward bob]

mmm, this is nice

brilliant

 

[2hats]

Right about now, in the Saturn time frame, Cassini is dying a fiery death in the upper atmosphere. We will see loss of signal in just under 90 minutes when it arrives at Earth.

NASA Canberra DSN antenna is listening to live bent-pipe data with ESA’s New Norcia antenna also recording as a back up to make sure nothing is missed.

 

[Crispy]

I was disappointed to learn that the actual disintegration happens far higher than any visible atmosphere, so the striking image of it dying in blue skies is a fabrication

 

[2hats]

I was disappointed to learn that the actual disintegration happens far higher than any visible atmosphere, so the striking image of it dying in blue skies is a fabrication

Indeed it is. Lot of artistic license taken. In fact it’ll be spinning wildly out of control, tumbling first, as the fine attitude control thrusters are overwhelmed/run out of propellant. This failure of pointing will of course be what leads to the loss of signal and not the (subsequent, inevitable) violent destruction. Unfortunately the sweep rate will probably be too high to pick up random subsequent data but maybe they will get a burst or two of momentary carrier?

 

[petee]

direct link:
| NASA
there's commentary on the public channel, and a bare feed of the control room on the media channel

 

[editor]

If this world had any sense of priorities, Cassini would be front page news everywhere.