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

Comments and questions about the APOD on the main view screen.
User avatar
APOD Robot
Otto Posterman
Posts: 2940
Joined: Fri Dec 04, 2009 3:27 am

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

Postby APOD Robot » Wed Jan 25, 2017 5:28 am

Image 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.

<< Previous APOD This Day in APOD Next APOD >>

User avatar
neufer
Vacationer at Tralfamadore
Posts: 14190
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

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

Postby neufer » Wed Jan 25, 2017 5:50 am

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

ta152h0
Schooled
Posts: 1239
Joined: Mon Aug 29, 2005 12:46 am
Location: Auburn, Washington, USA

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

Postby ta152h0 » Wed Jan 25, 2017 6:03 am

Icarus, the robotic version bids adieu
Wolf Kotenberg

Javachip3

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

Postby Javachip3 » Wed Jan 25, 2017 11:06 am

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
Schooled
Posts: 1239
Joined: Mon Aug 29, 2005 12:46 am
Location: Auburn, Washington, USA

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

Postby ta152h0 » Wed Jan 25, 2017 11:22 am

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
Wolf Kotenberg

User avatar
neufer
Vacationer at Tralfamadore
Posts: 14190
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

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

Postby neufer » Wed Jan 25, 2017 12:10 pm

Javachip3 wrote:
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.
Art Neuendorffer

staarchild

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

Postby staarchild » Wed Jan 25, 2017 12:53 pm

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
Ensign
Posts: 46
Joined: Tue Mar 26, 2013 10:18 pm

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

Postby bls0326 » Wed Jan 25, 2017 2:12 pm

what a dance.

User avatar
Chris Peterson
Abominable Snowman
Posts: 13119
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

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

Postby Chris Peterson » Wed Jan 25, 2017 2:42 pm

neufer wrote:
Javachip3 wrote: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

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

User avatar
Chris Peterson
Abominable Snowman
Posts: 13119
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

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

Postby Chris Peterson » Wed Jan 25, 2017 2:45 pm

staarchild wrote: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.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

User avatar
Ann
4725 Å
Posts: 8381
Joined: Sat May 29, 2010 5:33 am

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

Postby Ann » Wed Jan 25, 2017 2:48 pm

Chris Peterson wrote:
neufer wrote:
Javachip3 wrote: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
Color Commentator

Steve Dutch

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

Postby Steve Dutch » Wed Jan 25, 2017 3:06 pm

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.

User avatar
Chris Peterson
Abominable Snowman
Posts: 13119
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

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

Postby Chris Peterson » Wed Jan 25, 2017 3:07 pm

Ann wrote:
Chris Peterson wrote:
neufer wrote:
    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!
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

suicidejunkie
Ensign
Posts: 17
Joined: Wed Oct 21, 2015 6:46 pm

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

Postby suicidejunkie » Wed Jan 25, 2017 7:54 pm

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.

User avatar
MarkBour
Science Officer
Posts: 458
Joined: Mon Aug 26, 2013 2:44 pm
Location: Illinois, USA

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

Postby MarkBour » Wed Jan 25, 2017 9:22 pm

bls0326 wrote: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.

neufer wrote: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/grand-finale/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.
Mark Goldfain

User avatar
neufer
Vacationer at Tralfamadore
Posts: 14190
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

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

Postby neufer » Wed Jan 25, 2017 10:21 pm

MarkBour wrote:
neufer wrote:
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/grand-finale/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 :!:
Art Neuendorffer

User avatar
MarkBour
Science Officer
Posts: 458
Joined: Mon Aug 26, 2013 2:44 pm
Location: Illinois, USA

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

Postby MarkBour » Thu Jan 26, 2017 2:53 am

neufer wrote:That's a lot of F...Ring orbits :!:

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

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.
Mark Goldfain

geoffmo

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

Postby geoffmo » Fri Jan 27, 2017 5:54 am

A pig. In gumboots. Lives on Saturn?

Javachip3

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

Postby Javachip3 » Sat Jan 28, 2017 9:14 am

Chris Peterson wrote: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.

User avatar
neufer
Vacationer at Tralfamadore
Posts: 14190
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

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

Postby neufer » Sat Jan 28, 2017 1:53 pm

Javachip3 wrote:
Chris Peterson wrote:
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.
Art Neuendorffer

User avatar
geckzilla
Ocular Digitator
Posts: 8571
Joined: Wed Sep 12, 2007 12:42 pm
Location: Modesto, CA

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

Postby geckzilla » Sat Jan 28, 2017 10:06 pm

You are never gonna argue an essentialist's mind out of essentialism with facts and things like that.
Just call me "geck" because "zilla" is like a last name.

User avatar
neufer
Vacationer at Tralfamadore
Posts: 14190
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

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

Postby neufer » Sun Jan 29, 2017 5:45 am

geckzilla wrote:
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.
Art Neuendorffer

Javachip3

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

Postby Javachip3 » Sun Jan 29, 2017 9:34 am

neufer wrote:
    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.

User avatar
Ann
4725 Å
Posts: 8381
Joined: Sat May 29, 2010 5:33 am

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

Postby Ann » Sun Jan 29, 2017 10:17 am

Javachip3 wrote:
neufer wrote:
    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
Color Commentator

User avatar
Chris Peterson
Abominable Snowman
Posts: 13119
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

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

Postby Chris Peterson » Sun Jan 29, 2017 3:40 pm

Javachip3 wrote: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.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com


Return to “The Bridge: Discuss an Astronomy Picture of the Day”

Who is online

Users browsing this forum: No registered users and 3 guests