APOD: Cassini's Grand Finale Tour at Saturn (2017 Jan 25)

[APOD Robot]

Cassini's Grand Finale Tour at Saturn

Explanation: Cassini is being prepared to dive into Saturn. The robotic spacecraft that has been orbiting and exploring Saturn for over a decade will end its mission in September with a spectacular atmospheric plunge. Pictured here is a diagram of Cassini's remaining orbits, each taking about one week. Cassini is scheduled to complete a few months of orbits that will take it just outside Saturn's outermost ring F. Then, in April, Titan will give Cassini a gravitational pull into Proximal orbits, the last of which, on September 15, will impact Saturn and cause the spacecraft to implode and melt. Cassini's Grand Finale orbits are designed to record data and first-ever views from inside the rings -- between the rings and planet -- as well as some small moons interspersed in the rings. Cassini's demise is designed to protect any life that may occur around Saturn or its moons from contamination by Cassini itself.

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[neufer]

How many F...Ring orbits is Cassini going to do?

[ta152h0]

Icarus, the robotic version bids adieu

[Javachip3]

It's nice that we are crashing Cassini into Saturn to prevent biological contamination of any liquid water oceans on Saturn's moons. But, has anyone considered the consequences of dropping 33 kg of plutonium-238 onto the heads of highly intelligent Saturnians?

[ta152h0]

highly intelligent saturnians would have found Cassini by now. ( and Cassini would have told JPL ) And i think the sun is a better dumping ground ) Highly dumb saturnians would ? maybe not. Remember, this is a giant gas planet

[neufer]

It's nice that we are crashing Cassini into Saturn to prevent biological contamination of any liquid water oceans on Saturn's moons. But, has anyone considered the consequences of dropping 33 kg of plutonium-238 onto the heads of highly intelligent Saturnians?

• Those Jovial guys would just laugh it off.

[staarchild]

it is best to bring cassini probe back to earth for recycling. people who think that they have the right to abandon space probes to interstellar space are practicing environmental cannibalism. if nasa esa cannot program cassini to return to earth then extraterrestrial alien should be summoned to retrieve the hardware and bring it back. for the second time since the earth was created the elements comprising the space probe hardware shall have paswsed through the earth's event horizon. a similar situation exists for the other abandoned space probes: new horizons; dawn space probe; herschel; planck; voyager 1 & 2; pioneer 10 ... ...

[bls0326]

what a dance.

[Chris Peterson]

It's nice that we are crashing Cassini into Saturn to prevent biological contamination of any liquid water oceans on Saturn's moons. But, has anyone considered the consequences of dropping 33 kg of plutonium-238 onto the heads of highly intelligent Saturnians?

• Those Jovial guys would just laugh it off.

Of course they would. They live next door, and are unaffected.

[Chris Peterson]

it is best to bring cassini probe back to earth for recycling. people who think that they have the right to abandon space probes to interstellar space are practicing environmental cannibalism. if nasa esa cannot program cassini to return to earth then extraterrestrial alien should be summoned to retrieve the hardware and bring it back. for the second time since the earth was created the elements comprising the space probe hardware shall have paswsed through the earth's event horizon. a similar situation exists for the other abandoned space probes: new horizons; dawn space probe; herschel; planck; voyager 1 & 2; pioneer 10 ... ...

More total mass of Earth material has been ejected to other planets by natural phenomena than by the deliberate actions of humans. And there's nothing found in any of it, natural or man-made, that isn't already out there in much greater quantities.

[Ann]

It's nice that we are crashing Cassini into Saturn to prevent biological contamination of any liquid water oceans on Saturn's moons. But, has anyone considered the consequences of dropping 33 kg of plutonium-238 onto the heads of highly intelligent Saturnians?

• Those Jovial guys would just laugh it off.

Of course they would. They live next door, and are unaffected.

Next door, I don't know... never less than 4 A.U. away, and probably never even that close.

Ann

[Steve Dutch]

So, for the folks who posted a few days ago on the Daphnis image about wanting close-ups of the rings, this will be your best shot.

[Chris Peterson]

• Those Jovial guys would just laugh it off.

Of course they would. They live next door, and are unaffected.

Next door, I don't know... never less than 4 A.U. away, and probably never even that close.

Well, that microbe in your belly probably says the same thing about your next door neighbor!

[suicidejunkie]

There is something to be said about the idea of launching a hundred Saturn Vs to assemble a Saturn V in orbit and send it to Saturn in order to return a small probe from Saturn.

[MarkBour]

what a dance.

I had the same reaction. It's a nice plan, and I think it will get some really good "ring-side" data. I wonder what the probability is that it might have a serious collision before it gets through with this dance. I assume NASA planners know that it will be just far enough away from the F-ring to have only a very tiny chance of a collision.

How many F...Ring orbits is Cassini going to do?

Although this site is throwing an https error, it looks good:
http://saturn.jpl.nasa.gov/mission/gran ... e/overview
According to that site, there will be 20 F-Ring orbits, but that process started on Nov 30, so, if they take about a week each, it must have already done about half of them (?) Then there will be 22 dives "beneath" the rings ("beneath" here meaning a periapsis closer to Saturn than the rings) and the site has a nice countdown clock.

[neufer]

How many F...Ring orbits is Cassini going to do?

Although this site is throwing an https error, it looks good:
http://saturn.jpl.nasa.gov/mission/gran ... e/overview
According to that site, there will be 20 F-Ring orbits, but that process started on Nov 30, so, if they take about a week each, it must have already done about half of them (?) Then there will be 22 dives "beneath" the rings ("beneath" here meaning a periapsis closer to Saturn than the rings) and the site has a nice countdown clock.

• That's a lot of F...Ring orbits

[MarkBour]

That's a lot of F...Ring orbits

Yep. And in April, it will be done with the whole F...Ring lot of them.

I just noticed that the diagram notes that the final fouetté in this dance will happen about "noon local time", a nice touch. Will Hubble try to view a fireball? It seems like it would be easier to see if the entry was rotated to a sunrise or sunset position. Will local noon give Cassini its best final readings/photo? I wonder when it will send its last bit of data. I still don't think NASA should murder this hero. I think in a couple of hundred years, it would fetch a really nice price as a collector's item.

[geoffmo]

A pig. In gumboots. Lives on Saturn?

[Javachip3]

More total mass of Earth material has been ejected to other planets by natural phenomena than by the deliberate actions of humans. And there's nothing found in any of it, natural or man-made, that isn't already out there in much greater quantities.

I disagree. Currently there may not be a single atom of plutonium-238 on Saturn. That will change on September 15.

[neufer]

More total mass of Earth material has been ejected to other planets by natural phenomena than by the deliberate actions of humans. And there's nothing found in any of it, natural or man-made, that isn't already out there in much greater quantities.

I disagree. Currently there may not be a single atom of plutonium-238 on Saturn. That will change on September 15.

• 1) About one in every trillion atoms is Uranium-238.
  
  2) Plutonium-238 was synthesized on Earth by Glenn Seaborg by bombarding uranium-238 with high energy deuterons(, creating neptunium-238, which then decays to form plutonium-238).
  
  3) Plutonium-238 is synthesized in Saturn every day from naturally occurring Uranium-238 and high energy deuterons due to natural radioactivity, cosmic rays, etc.

[geckzilla]

You are never gonna argue an essentialist's mind out of essentialism with facts and things like that.

[neufer]

You are never gonna argue an essentialist's mind out of essentialism with facts and things like that.

KING LEAR: First let me talk with this philosopher.

[Javachip3]

• 1) About one in every trillion atoms is Uranium-238. NOT ON SATURN
  
  2) Plutonium-238 was synthesized on Earth by Glenn Seaborg IN THE LABORATORY by bombarding uranium-238 with high energy deuterons(, creating neptunium-238, which then decays to form plutonium-238).
  
  3) Plutonium-238 is synthesized in Saturn every day from naturally occurring Uranium-238 and high energy deuterons due to natural radioactivity, cosmic rays, etc. NO EVIDENCE OF THIS

On Earth, there may be a few naturally occurring plutonium atoms for every trillion uranium atoms. Saturn is believed to have a rocky core, but this is not confirmed, nor is its chemical composition known. At the very least, it is possible that the 33 kg of plutonium aboard Cassini may be nontrivial compared to the total naturally occurring plutonium (if any) on Saturn.

[Ann]

• 1) About one in every trillion atoms is Uranium-238. NOT ON SATURN
  
  2) Plutonium-238 was synthesized on Earth by Glenn Seaborg IN THE LABORATORY by bombarding uranium-238 with high energy deuterons(, creating neptunium-238, which then decays to form plutonium-238).
  
  3) Plutonium-238 is synthesized in Saturn every day from naturally occurring Uranium-238 and high energy deuterons due to natural radioactivity, cosmic rays, etc. NO EVIDENCE OF THIS

On Earth, there may be a few naturally occurring plutonium atoms for every trillion uranium atoms. Saturn is believed to have a rocky core, but this is not confirmed, nor is its chemical composition known. At the very least, it is possible that the 33 kg of plutonium aboard Cassini may be nontrivial compared to the total naturally occurring plutonium (if any) on Saturn.

It is not okay to change neufer's quote by adding your own comments inside his quote.

So, NOT ON SATURN was added by you, IN THE LABORATORY was added by you, and NO EVIDENCE OF THIS was added by you.

We can never have any sort of honest discussion if we don't respect what the other person said and didn't say.

Don't attribute your own opinions to neufer! Don't add words inside his quote!

Ann

[Chris Peterson]

On Earth, there may be a few naturally occurring plutonium atoms for every trillion uranium atoms. Saturn is believed to have a rocky core, but this is not confirmed, nor is its chemical composition known.

The figure of one out of a trillion atoms being U-238 represents a cosmic abundance, not a value observed on Earth. This amount was present in the pre-solar nebula from which the Solar System formed, and there is no mechanism that would have separated it such that none ended up in the gas giants. We do, in fact, have a pretty good idea what elements and elemental abundances make up Saturn, just not the details of the specific chemistry and distribution. Almost certainly, there is something on the order of 100 trillion kilograms of U-238 in Saturn, which means that plutonium is continuously being created, in quantities that dwarf the 33 kg that will be introduced by the RTG burning up.