The Cassini spacecraft crashed into Saturn, ending a successful 20-year mission

[Baz]

PASADENA, Calif. — NASA scientists just received their last message from the Cassini spacecraft, which plunged into Saturn early Friday morning. Those final bits of data signal the end of one of the most successful planetary science missions in history.

“The signal from the spacecraft is gone and within the next 45 seconds so will be the spacecraft,” program manager Earl Maize reported from mission control at NASA's Jet Propulsion Laboratory, just after 4:55 a.m. local time. “This has been an incredible mission, an incredible spacecraft, and you're all an incredible team.”

One of the last pieces of data captured by Cassini was an infrared image of the place into which it took its final plunge. The image, taken 15 hours before the spacecraft's demise, reveals a spot on Saturn's dark side just north of the planet's equator where the spacecraft disintegrated shortly after losing contact with Earth.

Cassini was the first probe to orbit Saturn. Built and operated at JPL, it was launched in 1997 and inserted into orbit in 2004. The spacecraft revealed the structure of Saturn's rings and, by delivering the Huygens probe to the moon Titan, executed the first landing of a spacecraft in the outer solar system. It also exposed two moons — Titan, a land of methane lakes, and Enceladus, which has jets of water streaming from its southern pole — as prime targets in the search for life beyond Earth.

After 13 years in orbit, Cassini leaves researchers with still more mysteries to ponder: They don't know the length of the Saturn day or understand the quirks of its magnetic field. And it will fall to a future mission to discover whether one of Saturn's potentially habitable moons could truly be home to alien life.

MORE HERE

[Jim Richards]

Friggin' litter bugs

[Bill Douglas]

After 20 years. They must have had someone new driving it.

[herr_oberst]

There was a terrific story on Science Friday today about this.

Lots of data compiled about Saturn in the last 20 plus years thanks to this program!!

Science!

[mjohnson]

Originally Posted by Jim Richards

Friggin' litter bugs

Worse than that - Plutonium litter. Like the worst kind of all of the Plutoniums!

We made the 238Pu heat sources for the radioisotopic thermal generators that powered the thing. Lots of us signed a plaque that got reproduced really small and stuck onto the thing. Kind of cool to think that my signature just burned up into Saturn!

Super well built - many have reentered from Earth orbit with no release. This one (the heat source) will probably just fall to "whatever" is the surface and sit there for another 20-50 years when it will eventually rupture from the helium generated by the rapid 238Pu decay. Then many Saturnains might perish. We may never know...

We also kind of invented a few of the onboard instruments, but those were on the conehead side of the lab. I'm just a (one-time Pu) materials guy so I don't understand those fancy widgets.

(also see our 238Pu trinkets most recently on the Mars Rovers!)

[GH85Carrera]

So we just started a war with the Saturn people? Dropping radioactive waste on their planet.

[RKDinOKC]

We should be proud that we were able to hit something that far away. It does kind of look like a target from the right angle though.

[MMiller]

Originally Posted by mjohnson

Worse than that - Plutonium litter. Like the worst kind of all of the Plutoniums!

We made the 238Pu heat sources for the radioisotopic thermal generators that powered the thing. Lots of us signed a plaque that got reproduced really small and stuck onto the thing. Kind of cool to think that my signature just burned up into Saturn!

Super well built - many have reentered from Earth orbit with no release. This one (the heat source) will probably just fall to "whatever" is the surface and sit there for another 20-50 years when it will eventually rupture from the helium generated by the rapid 238Pu decay. Then many Saturnains might perish. We may never know...

We also kind of invented a few of the onboard instruments, but those were on the conehead side of the lab. I'm just a (one-time Pu) materials guy so I don't understand those fancy widgets.

(also see our 238Pu trinkets most recently on the Mars Rovers!)

Love this post! The rest of us in NM always wonder what kind of wizardry you kids are up to in those labs..

[scottmandue]

Pffft! Big brother Voyager left the solar system, merged with a alien probe and came back to kick our butts!

[Steve Carlton]

Same thing with Nomad.

[pavulon]

The breadth and depth of people on or lurking this message board never ceases to amaze.

[mjohnson]

Originally Posted by GH85Carrera

So we just started a war with the Saturn people? Dropping radioactive waste on their planet.

I saw somewhere that, legit, it was intentionally crashed into Saturn because just to let it die/drift in orbit might let it crash into one of the moons and contaminate them - messing up whatever lives there or just future research. They figured nobody will ever stumble upon our rad waste on the surface(?) of Saturn. Hey, it was the '90s. Jean shorts seemed sensible then too...

I'd love to track that line of reasoning further than whatever threads of mainstream coverage brought it to me today. With a ~90y half life there won't be much left when we're wandering around on some Saturn-moon, at least by my estimation.

[mjohnson]

Originally Posted by MMiller

Love this post! The rest of us in NM always wonder what kind of wizardry you kids are up to in those labs..

Powerpoint lately, at least for me.

Back in the Pu area we called the glowing cylinder of 238Pu-oxide shown in the linked wiki the "Senator Ball". It was retired before I showed up in '96 but, kept in a well insulated box, it had enough heat generated by decay that it would glow incandescently. Was very impressive for VIPs touring the facility.

Evidently the repeated boxing/unboxing of it cycled its temps enough that it began to crumble - and anything made of that isotope is a nightmare to clean up. It decays so energetically that, according to lore, it will propel itself around the room - soiling areas you just deconned.

https://en.wikipedia.org/wiki/Plutonium-238

I'm sad that I never got to see the Senator Ball. I think it's still in a box somewhere here in LA.

Did five years in Pu. Rad stuff, at least safe-ish things like Pu, don't bother me in the slightest - BUT - it is darn strange to pick something up and just feel it generating heat right there in your hands.

[Tervuren]

I remember as a kid reading about the launch, and thinking it would take forever to get there.

That was back before Popular science went unreadable.