Hubble finds additional evidence of water vapor plumes on Europa

The existence of plumes would make studying the moon's interior ocean easier.

Read the whole story

 

[enderwiggin21]

<Insert 2010 quote here>

I'm going with:

"Easy as cake."

 

[DCRoss]

enderwiggin21[/url]":2rz57p3s]<Insert 2010 quote here>

"There's a message coming in from HAL. It says:

WHAT DID WE TELL YOU ABOUT EUROPA?
I WARNED YOU, BUT DID YOU LISTEN TO ME?
OH NO, YOU KNEW, DIDN'T YOU?
OH, IT'S A HARMLESS LITTLE MOON, ISN'T IT?"

 

[THavoc]

Pfft. Stupid aliens telling us superior humans what to do!

 

[Asvarduil]

Dammit DCRoss ninja'd me. I was about to bring up the required "Attempt no landing there!" thing just to get it out of the way, but before I could be witless, he just had to jump in.



I'm going to look for a suitable pony for this thread, and this time it's not THavoc's fault (yet.)

 

[Veritas super omens]

Trouble drilling? Call Ben Affleck and Bruce Willis. They always get their depth, just watch Armageddon. I watched it again recently, rapidly becoming my unintentional camp favorite. Just amazingly stupid. And Buschemi was in rare form, even for him!

 

[THavoc]

Asvarduil[/url]":1zbei811]Dammit DCRoss ninja'd me. I was about to bring up the required "Attempt no landing there!" thing just to get it out of the way, but before I could be witless, he just had to jump in.



I'm going to look for a suitable pony for this thread, and this time it's not THavoc's fault (yet.)

Damn it man!

 

[Mmm...Burritos]

If "the radiation from nearby Jupiter would kill a human in a matter of hours or days", then why would we expect to find life there?

 

[THavoc]

Mmm...Burritos[/url]":1xnnki2w]If "the radiation from nearby Jupiter would kill a human in a matter of hours or days", then why would we expect to find life there?

The ice acts as a insulator protecting any life deep in the ocean.

 

[Asvarduil]

THavoc[/url]":2vssykl4]

Asvarduil[/url]":2vssykl4]Dammit DCRoss ninja'd me. I was about to bring up the required "Attempt no landing there!" thing just to get it out of the way, but before I could be witless, he just had to jump in.



I'm going to look for a suitable pony for this thread, and this time it's not THavoc's fault (yet.)

Damn it man!

Ok now it's your fault - you typed words, with a keyboard. They reached the internet, the pony is now in your name.*

Back on topic, though, the options for researching Europa seem legion. In addition to cubesats and direct fly-throughs, what about maybe deploying micro-rovers or stationary sensors directly to the planet? As noted, we've only had cursory observations of Europa; it seems like this is the perfect excuse to get more hardware out there, and to learn more.

Also, think about the PR. If you can get some awesome shots of another world, it could surely drum up public interest not only in the mission - thus resulting in maybe more money for NASA - but also people to develop into the astrophysicists and astroengineers of tomorrow. Look at what the flyby of Pluto did for the space program!

*: If this were a political thread, there'd already be a pony. I have great respect for interstellar exploration, though. I'll refrain from using this thread's allowance of pony until it's clear that it's over.

 

[THavoc]

Asvarduil[/url]":3c0yseoh]

THavoc[/url]":3c0yseoh]

Asvarduil[/url]":3c0yseoh]Dammit DCRoss ninja'd me. I was about to bring up the required "Attempt no landing there!" thing just to get it out of the way, but before I could be witless, he just had to jump in.



I'm going to look for a suitable pony for this thread, and this time it's not THavoc's fault (yet.)

Damn it man!

Ok now it's your fault - you typed words, with a keyboard. They reached the internet, the pony is now in your name.

I am ashamed.

 

[bskin]

Mmm...Burritos[/url]":2q3o5ht0]If "the radiation from nearby Jupiter would kill a human in a matter of hours or days", then why would we expect to find life there?

There's kilometers of ice protecting the sub-surface ocean. Also, there's lots of microbial life that is resistant to radiation.

 

[Statistical]

If "the radiation from nearby Jupiter would kill a human in a matter of hours or days", then why would we expect to find life there?

We wouldn't on the surface but water is an amazing radiation shield. Even a few dozen meters would make a solid shield and the ice crust is estimated to be between 10 and 30 km thick.

 

[Veritas super omens]

We should petition NASA to name one of its hardware devices My Little Pony.

 

[Asvarduil]

Veritas super omens[/url]":3knrpgi9]We should petition NASA to name one of its hardware devices My Little Pony.

A deep space probe named Twilight Sparkle, perhaps?

...Actually, that's not a half bad idea, when you think about it.

 

[Dilbert]

JPL is already planning an orbiter with the ability to fly through and sample these plumes, among other things such as finding a suitable landing site for a subsequent mission. Exciting.

 

[THavoc]

Asvarduil[/url]":2zc9rny0]

Veritas super omens[/url]":2zc9rny0]We should petition NASA to name one of its hardware devices My Little Pony.

A deep space probe named Twilight Sparkle, perhaps?

...Actually, that's not a half bad idea, when you think about it.

That would be a good way to end all life on Earth.

I'd recommend against it.

 

[Asvarduil]

THavoc[/url]":12tgi011]

Asvarduil[/url]":12tgi011]

Veritas super omens[/url]":12tgi011]We should petition NASA to name one of its hardware devices My Little Pony.

A deep space probe named Twilight Sparkle, perhaps?

...Actually, that's not a half bad idea, when you think about it.

That would be a good way to end all life on Earth.

I'd recommend against it.

It's better than naming a probe 'Fluttershy'. I mean, you're practically begging for a comms failure with that name.

 

[SiberX]

Whenever discussion about probes on Europa comes up, I wonder about the feasibility of landing a two-part probe consisting of:

-A surface module, that does the initial landing and contains high-gain antennas to communicate with earth
-A submersible/penetrator module, heated and powered by RTGs to keep it at 70-80 celsius
-A long (5-10km) spool of fibre optic cable, held inside the sub and spooled out as the probe slowly melts its way through the icy crust

The whole assembly lands, and then the lander just plunks the warm sub module on the ice and lets it work its way down to the subsurface ocean. A few years later, there's a few km (hopefully they find a thin part of the crust to make it more manageable) of communication cable connecting the surface with the ocean, and your sub could then send data back to the surface for transmission. If you were clever enough you could even detatch the communication tether and roam deeper (returning to upload gathered data) but simply dangling under the tether cable might provide lots of useful data already.

Is such a plan possible? Is a long enough (very thin) fibre optic infeasibly large? Do the ice sheets move too much to prevent cable breakage? Do RTGs not put out enough heat to melt through the ice?

 

[peipas]

And with only a very tenuous atmosphere, it is cold: -210 degrees Celsius.

For we yanks outside the scientific community, that is -346 degrees Fahrenheit, or just over 100 degrees warmer than absolute zero.

 

[halse]

"The radiation from nearby Jupiter would kill a human in a matter of hours or days."

Careful. The radiation is not from Jupiter but the "bow shock" caused by the interaction of Jupiter's magnetic field with the solar wind. Also, a human would be inside of a space ship which would provide pretty good protection from those low energy protons.

 

[Asvarduil]

peipas[/url]":1gfqa9ay]

And with only a very tenuous atmosphere, it is cold: -210 degrees Celsius.

For we yanks outside the scientific community, that is -346 degrees Fahrenheit, or just over 100 degrees warmer than absolute zero.

Absolute zero is -310.4 C F, correct? (I could be off by a few decimal points; in my day to day job I never have to worry with absolute zero yet. Or the Kelvin scale at all, for that matter.)

Edit: Note to self - don't mix up Metric and Imperial. Bad things happen.

 

[Statistical]

SiberX[/url]":1h0r3cfl]Whenever discussion about probes on Europa comes up, I wonder about the feasibility of landing a two-part probe consisting of:

-A surface module, that does the initial landing and contains high-gain antennas to communicate with earth
-A submersible/penetrator module, heated and powered by RTGs to keep it at 70-80 celsius
-A long (5-10km) spool of fibre optic cable, held inside the sub and spooled out as the probe slowly melts its way through the icy crust

The whole assembly lands, and then the lander just plunks the warm sub module on the ice and lets it work its way down to the subsurface ocean. A few years later, there's a few km (hopefully they find a thin part of the crust to make it more manageable) of communication cable connecting the surface with the ocean, and your sub could then send data back to the surface for transmission. If you were clever enough you could even detatch the communication tether and roam deeper (returning to upload gathered data) but simply dangling under the tether cable might provide lots of useful data already.

Is such a plan possible? Is a long enough (very thin) fibre optic infeasibly large? Do the ice sheets move too much to prevent cable breakage? Do RTGs not put out enough heat to melt through the ice?

RTGs put out enough heat to melt the ice. The nice thing about RTG is that if you need more heat, just bring more nuclear material until you have the thermal output you require. You would pump meltwater past a heat exchanger and direct the heated stream downward where it melts more ice. The probe would descend in a bubble of self created liquid water. The formerly liquid water above the probe would eventually freeze solid. So you would have a slowly descending bubble of liquid water in an otherwise solid block of ice.

Communication is the big challenge. Any trailing fiber optic cable would end up in solid ice very quickly. The ice crust does move sometimes meters a day so designing a cable and deployment system that would allow your "landline" to survive for an extended period of time would be a challenge.

Even if you solved communication we are probably at least two decades away from any such mission. NASA funding and the lack of detailed information on Europa being the major obstacles.

 

[Statistical]

Asvarduil[/url]":2lr443qq]

peipas[/url]":2lr443qq]

And with only a very tenuous atmosphere, it is cold: -210 degrees Celsius.

For we yanks outside the scientific community, that is -346 degrees Fahrenheit, or just over 100 degrees warmer than absolute zero.

Absolute zero is -310.4 C, correct? (I could be off by a few decimal points; in my day to day job I never have to worry with absolute zero yet. Or the Kelvin scale at all, for that matter.)

−273.15°C. So -210C is ~63 Kelvin.

 

[Asvarduil]

Statistical[/url]":1vvhd8bf]

Asvarduil[/url]":1vvhd8bf]

peipas[/url]":1vvhd8bf]

And with only a very tenuous atmosphere, it is cold: -210 degrees Celsius.

For we yanks outside the scientific community, that is -346 degrees Fahrenheit, or just over 100 degrees warmer than absolute zero.

Absolute zero is -310.4 C, correct? (I could be off by a few decimal points; in my day to day job I never have to worry with absolute zero yet. Or the Kelvin scale at all, for that matter.)

−273.15°C. So -210C is ~63 Kelvin.

Crap, I think I did a Farenheit <-> Celsius screw-up. It's a good thing I'm not building a spaceship right now.

 

[kisunssi]

William Sparks... astronomer with the Space Telescope Science Institute in Baltimore who led the research... "The problem is that there may be something we don’t understand about the instrument or what Europa looks like in ultraviolet light. These are difficult wavelengths for Hubble." Sparks added that aside from an instrument error, he could not think of any other explanation. "I'm not aware of any natural explanation for this besides water plumes."

Intergalactic space whales?

 

[Skyfire77]

kisunssi[/url]":v7un4l9g]

William Sparks... astronomer with the Space Telescope Science Institute in Baltimore who led the research... "The problem is that there may be something we don’t understand about the instrument or what Europa looks like in ultraviolet light. These are difficult wavelengths for Hubble." Sparks added that aside from an instrument error, he could not think of any other explanation. "I'm not aware of any natural explanation for this besides water plumes."

Intergalactic space whales?

Let's hope it's the Star Wars space whales and not the ones from Star Trek.

 

[dtich]

enderwiggin21[/url]":1n2fmoq4]<Insert 2010 quote here>

I'm going with:

"Easy as cake."

"Pie. Easy as Pie."

i'm gonna go with: "All these worlds are yours except Europa. Attempt no landing there."

......LOL. SO ninja'd. by commenters AND the article itself. didn't even remember. it's too hot today.

 

[krimhorn]

Asvarduil[/url]":3tj5prku]Dammit DCRoss ninja'd me. I was about to bring up the required "Attempt no landing there!" thing just to get it out of the way, but before I could be witless, he just had to jump in.

Eric ninja'd you both. In the first 'graph.

I wonder what the odds of scooping up some water and finding microbes in it would be.

 

[jason8957]

Statistical[/url]":2xcr5f24]

SiberX[/url]":2xcr5f24]Whenever discussion about probes on Europa comes up, I wonder about the feasibility of landing a two-part probe consisting of:

-A surface module, that does the initial landing and contains high-gain antennas to communicate with earth
-A submersible/penetrator module, heated and powered by RTGs to keep it at 70-80 celsius
-A long (5-10km) spool of fibre optic cable, held inside the sub and spooled out as the probe slowly melts its way through the icy crust

The whole assembly lands, and then the lander just plunks the warm sub module on the ice and lets it work its way down to the subsurface ocean. A few years later, there's a few km (hopefully they find a thin part of the crust to make it more manageable) of communication cable connecting the surface with the ocean, and your sub could then send data back to the surface for transmission. If you were clever enough you could even detatch the communication tether and roam deeper (returning to upload gathered data) but simply dangling under the tether cable might provide lots of useful data already.

Is such a plan possible? Is a long enough (very thin) fibre optic infeasibly large? Do the ice sheets move too much to prevent cable breakage? Do RTGs not put out enough heat to melt through the ice?

RTGs currently put out enough heat to melt the ice. The nice thing about RTG is that is you need more heat you just bring more nuclear material. You can find the right amount to melt a path for your probe in a reasonable amount of time. In essence you would pump water past a heat exchanger and direct it downward where it melts more ice. The probe would descend in a bubble of self created liquid water. The formerly liquid water above the probe would eventually freeze solid. So you would have a slowly descending bubble of liquid water in an otherwise solid block of ice.

Communication is the big challenge. Any trailing fiber optic cable would be in solid ice very quickly. The ice does move sometimes meters a day so designing a cable and deployment system that would allow your "landline" to survive would be a challenge.

Even if you solved communication we are probably at least two decades away from any such mission. NASA funding and the lack of detailed information on Europa being the major obstacles.

That and we are dropping a dirty bomb on a place we think might have life.

 

[Statistical]

jason8957[/url]":3m3k9ykg]

Statistical[/url]":3m3k9ykg]

SiberX[/url]":3m3k9ykg]Whenever discussion about probes on Europa comes up, I wonder about the feasibility of landing a two-part probe consisting of:

-A surface module, that does the initial landing and contains high-gain antennas to communicate with earth
-A submersible/penetrator module, heated and powered by RTGs to keep it at 70-80 celsius
-A long (5-10km) spool of fibre optic cable, held inside the sub and spooled out as the probe slowly melts its way through the icy crust

The whole assembly lands, and then the lander just plunks the warm sub module on the ice and lets it work its way down to the subsurface ocean. A few years later, there's a few km (hopefully they find a thin part of the crust to make it more manageable) of communication cable connecting the surface with the ocean, and your sub could then send data back to the surface for transmission. If you were clever enough you could even detatch the communication tether and roam deeper (returning to upload gathered data) but simply dangling under the tether cable might provide lots of useful data already.

Is such a plan possible? Is a long enough (very thin) fibre optic infeasibly large? Do the ice sheets move too much to prevent cable breakage? Do RTGs not put out enough heat to melt through the ice?

RTGs currently put out enough heat to melt the ice. The nice thing about RTG is that is you need more heat you just bring more nuclear material. You can find the right amount to melt a path for your probe in a reasonable amount of time. In essence you would pump water past a heat exchanger and direct it downward where it melts more ice. The probe would descend in a bubble of self created liquid water. The formerly liquid water above the probe would eventually freeze solid. So you would have a slowly descending bubble of liquid water in an otherwise solid block of ice.

Communication is the big challenge. Any trailing fiber optic cable would be in solid ice very quickly. The ice does move sometimes meters a day so designing a cable and deployment system that would allow your "landline" to survive would be a challenge.

Even if you solved communication we are probably at least two decades away from any such mission. NASA funding and the lack of detailed information on Europa being the major obstacles.

That and we are dropping a dirty bomb on a place we think might have life.

RTGs aren't really that harmful unless you damage them and it takes a lot to damage them. We dropped one into the ocean from orbital velocities (was carried aboard Apollo13) and it was expected to remain intact.

BTW: 3.9 kg of plutonium slightly used available. Possible collector's item as it orbited the moon. Must pick up at Tonga Trench. Bring own transportation.

 

[SmokeTest]

jason8957[/url]":192lq6d1]

Statistical[/url]":192lq6d1]

SiberX[/url]":192lq6d1]Whenever discussion about probes on Europa comes up, I wonder about the feasibility of landing a two-part probe consisting of:

-A surface module, that does the initial landing and contains high-gain antennas to communicate with earth
-A submersible/penetrator module, heated and powered by RTGs to keep it at 70-80 celsius
-A long (5-10km) spool of fibre optic cable, held inside the sub and spooled out as the probe slowly melts its way through the icy crust

The whole assembly lands, and then the lander just plunks the warm sub module on the ice and lets it work its way down to the subsurface ocean. A few years later, there's a few km (hopefully they find a thin part of the crust to make it more manageable) of communication cable connecting the surface with the ocean, and your sub could then send data back to the surface for transmission. If you were clever enough you could even detatch the communication tether and roam deeper (returning to upload gathered data) but simply dangling under the tether cable might provide lots of useful data already.

Is such a plan possible? Is a long enough (very thin) fibre optic infeasibly large? Do the ice sheets move too much to prevent cable breakage? Do RTGs not put out enough heat to melt through the ice?

RTGs currently put out enough heat to melt the ice. The nice thing about RTG is that is you need more heat you just bring more nuclear material. You can find the right amount to melt a path for your probe in a reasonable amount of time. In essence you would pump water past a heat exchanger and direct it downward where it melts more ice. The probe would descend in a bubble of self created liquid water. The formerly liquid water above the probe would eventually freeze solid. So you would have a slowly descending bubble of liquid water in an otherwise solid block of ice.

Communication is the big challenge. Any trailing fiber optic cable would be in solid ice very quickly. The ice does move sometimes meters a day so designing a cable and deployment system that would allow your "landline" to survive would be a challenge.

Even if you solved communication we are probably at least two decades away from any such mission. NASA funding and the lack of detailed information on Europa being the major obstacles.

That and we are dropping a dirty bomb on a place we think might have life.

The real problem with RTGs is actually a lot more mundane, and something nobody has brought up yet. Namely, we don't have the materials to build any.

RTGs rely on plutonium to generate heat and power. Plutonium does not occur naturally in the universe except at trace levels. So all plutonium we have is manufactured in nuclear reactors. Back in 1988 the United States shut down plutonium production, and didn't reactivate it until recently, though production is limited to a handful of grams per year (scaling up is hard).

Limitations on nuclear technology designed to curb nuclear weapons programs also made it very difficult to produce plutonium for peaceful purposes. So, after 1988, basically all the plutonium we got came from Russia, and is of low quality (why would they sell the good stuff?). We have 35kg left, of which half has decayed so much that it's no longer useful for RTGs. The ~17kg left is essentially all already claimed.

NASA claims they aren't limited by plutonium, but this is at best misleading. It's a bit like saying you have enough materials to finish your work because you'll stop working once you run out. Similarly, NASA would be planning far more ambitious, and frequent, missions if they had more plutonium. For example, there was the proposed Jupiter Europa Orbiter mission, which was scrapped in favor of a more economical mission. Probably because the Jupiter Europa Orbiter mission would have required more plutonium than there currently exists on the planet in any form.

TL;DR: Earth is out of plutonium, and we don't know when we'll have more. Any plans predicated upon easy access to large amounts of plutonium are non-starters for at least a few decades.

 

[SixDegrees]

krimhorn[/url]"j5nsrvj]

Asvarduil[/url]"j5nsrvj]Dammit DCRoss ninja'd me. I was about to bring up the required "Attempt no landing there!" thing just to get it out of the way, but before I could be witless, he just had to jump in.

Eric ninja'd you both. In the first 'graph.

I wonder what the odds of scooping up some water and finding microbes in it would be.

Depends on whether those plumes are connected to the purported oceans kilometers below.

The geysers at Yellowstone, for instance, are fed by surface waters - not deep subterranean sources. They're more or less localized systems. Same could be true on Europa, with the system fed by the "kneading" of the surface mentioned in the article, and no connection with deeper water sources.

Or, it could be they're spraying Europan microbes all over the Jovian system.

I guess we'll have to wait and see.

 

[Dilbert]

SmokeTest[/url]":rtw5uu0i]

jason8957[/url]":rtw5uu0i]

Statistical[/url]":rtw5uu0i]

SiberX[/url]":rtw5uu0i]Whenever discussion about probes on Europa comes up, I wonder about the feasibility of landing a two-part probe consisting of:

-A surface module, that does the initial landing and contains high-gain antennas to communicate with earth
-A submersible/penetrator module, heated and powered by RTGs to keep it at 70-80 celsius
-A long (5-10km) spool of fibre optic cable, held inside the sub and spooled out as the probe slowly melts its way through the icy crust

The whole assembly lands, and then the lander just plunks the warm sub module on the ice and lets it work its way down to the subsurface ocean. A few years later, there's a few km (hopefully they find a thin part of the crust to make it more manageable) of communication cable connecting the surface with the ocean, and your sub could then send data back to the surface for transmission. If you were clever enough you could even detatch the communication tether and roam deeper (returning to upload gathered data) but simply dangling under the tether cable might provide lots of useful data already.

Is such a plan possible? Is a long enough (very thin) fibre optic infeasibly large? Do the ice sheets move too much to prevent cable breakage? Do RTGs not put out enough heat to melt through the ice?

RTGs currently put out enough heat to melt the ice. The nice thing about RTG is that is you need more heat you just bring more nuclear material. You can find the right amount to melt a path for your probe in a reasonable amount of time. In essence you would pump water past a heat exchanger and direct it downward where it melts more ice. The probe would descend in a bubble of self created liquid water. The formerly liquid water above the probe would eventually freeze solid. So you would have a slowly descending bubble of liquid water in an otherwise solid block of ice.

Communication is the big challenge. Any trailing fiber optic cable would be in solid ice very quickly. The ice does move sometimes meters a day so designing a cable and deployment system that would allow your "landline" to survive would be a challenge.

Even if you solved communication we are probably at least two decades away from any such mission. NASA funding and the lack of detailed information on Europa being the major obstacles.

That and we are dropping a dirty bomb on a place we think might have life.

The real problem with RTGs is actually a lot more mundane, and something nobody has brought up yet. Namely, we don't have the materials to build any.

RTGs rely on plutonium to generate heat and power. Plutonium does not occur naturally in the universe except at trace levels. So all plutonium we have is manufactured in nuclear reactors. Back in 1988 the United States shut down plutonium production, and didn't reactivate it until recently, though production is limited to a handful of grams per year (scaling up is hard).

Limitations on nuclear technology designed to curb nuclear weapons programs also made it very difficult to produce plutonium for peaceful purposes. So, after 1988, basically all the plutonium we got came from Russia, and is of low quality (why would they sell the good stuff?). We have 35kg left, of which half has decayed so much that it's no longer useful for RTGs. The ~17kg left is essentially all already claimed.

NASA claims they aren't limited by plutonium, but this is at best misleading. It's a bit like saying you have enough materials to finish your work because you'll stop working once you run out. Similarly, NASA would be planning far more ambitious, and frequent, missions if they had more plutonium. For example, there was the proposed Jupiter Europa Orbiter mission, which was scrapped in favor of a more economical mission. Probably because the Jupiter Europa Orbiter mission would have required more plutonium than there currently exists on the planet in any form.

TL;DR: Earth is out of plutonium, and we don't know when we'll have more. Any plans predicated upon easy access to large amounts of plutonium are non-starters for at least a few decades.

No worries. Kim Jong Un will trade us some Pu for a box of doughnuts.

 

[Dakke]

SmokeTest[/url]":zsqtqshj]

jason8957[/url]":zsqtqshj]

Statistical[/url]":zsqtqshj]

SiberX[/url]":zsqtqshj]Whenever discussion about probes on Europa comes up, I wonder about the feasibility of landing a two-part probe consisting of:

-A surface module, that does the initial landing and contains high-gain antennas to communicate with earth
-A submersible/penetrator module, heated and powered by RTGs to keep it at 70-80 celsius
-A long (5-10km) spool of fibre optic cable, held inside the sub and spooled out as the probe slowly melts its way through the icy crust

The whole assembly lands, and then the lander just plunks the warm sub module on the ice and lets it work its way down to the subsurface ocean. A few years later, there's a few km (hopefully they find a thin part of the crust to make it more manageable) of communication cable connecting the surface with the ocean, and your sub could then send data back to the surface for transmission. If you were clever enough you could even detatch the communication tether and roam deeper (returning to upload gathered data) but simply dangling under the tether cable might provide lots of useful data already.

Is such a plan possible? Is a long enough (very thin) fibre optic infeasibly large? Do the ice sheets move too much to prevent cable breakage? Do RTGs not put out enough heat to melt through the ice?

RTGs currently put out enough heat to melt the ice. The nice thing about RTG is that is you need more heat you just bring more nuclear material. You can find the right amount to melt a path for your probe in a reasonable amount of time. In essence you would pump water past a heat exchanger and direct it downward where it melts more ice. The probe would descend in a bubble of self created liquid water. The formerly liquid water above the probe would eventually freeze solid. So you would have a slowly descending bubble of liquid water in an otherwise solid block of ice.

Communication is the big challenge. Any trailing fiber optic cable would be in solid ice very quickly. The ice does move sometimes meters a day so designing a cable and deployment system that would allow your "landline" to survive would be a challenge.

Even if you solved communication we are probably at least two decades away from any such mission. NASA funding and the lack of detailed information on Europa being the major obstacles.

That and we are dropping a dirty bomb on a place we think might have life.

The real problem with RTGs is actually a lot more mundane, and something nobody has brought up yet. Namely, we don't have the materials to build any.

RTGs rely on plutonium to generate heat and power. Plutonium does not occur naturally in the universe except at trace levels. So all plutonium we have is manufactured in nuclear reactors. Back in 1988 the United States shut down plutonium production, and didn't reactivate it until recently, though production is limited to a handful of grams per year (scaling up is hard).

Limitations on nuclear technology designed to curb nuclear weapons programs also made it very difficult to produce plutonium for peaceful purposes. So, after 1988, basically all the plutonium we got came from Russia, and is of low quality (why would they sell the good stuff?). We have 35kg left, of which half has decayed so much that it's no longer useful for RTGs. The ~17kg left is essentially all already claimed.

NASA claims they aren't limited by plutonium, but this is at best misleading. It's a bit like saying you have enough materials to finish your work because you'll stop working once you run out. Similarly, NASA would be planning far more ambitious, and frequent, missions if they had more plutonium. For example, there was the proposed Jupiter Europa Orbiter mission, which was scrapped in favor of a more economical mission. Probably because the Jupiter Europa Orbiter mission would have required more plutonium than there currently exists on the planet in any form.

TL;DR: Earth is out of plutonium, and we don't know when we'll have more. Any plans predicated upon easy access to large amounts of plutonium are non-starters for at least a few decades.

A long term solution is the use of an alternative RTG power source like Americium-240; which has a half-life time of 432 years. NASA did have a solution in the form of the Advanced Sterling Radio-isotope Generator, which could have eeked the same amount of energy out of 1 kg of Pu-238 as the current MMRTGs get out of 4 kg. Alas, like many useful technology programs it was cancelled in 2013 due to budget cuts.

 

[jason8957]

Statistical[/url]":2qnzxb0y]

jason8957[/url]":2qnzxb0y]

Statistical[/url]":2qnzxb0y]

SiberX[/url]":2qnzxb0y]Whenever discussion about probes on Europa comes up, I wonder about the feasibility of landing a two-part probe consisting of:

-A surface module, that does the initial landing and contains high-gain antennas to communicate with earth
-A submersible/penetrator module, heated and powered by RTGs to keep it at 70-80 celsius
-A long (5-10km) spool of fibre optic cable, held inside the sub and spooled out as the probe slowly melts its way through the icy crust

The whole assembly lands, and then the lander just plunks the warm sub module on the ice and lets it work its way down to the subsurface ocean. A few years later, there's a few km (hopefully they find a thin part of the crust to make it more manageable) of communication cable connecting the surface with the ocean, and your sub could then send data back to the surface for transmission. If you were clever enough you could even detatch the communication tether and roam deeper (returning to upload gathered data) but simply dangling under the tether cable might provide lots of useful data already.

Is such a plan possible? Is a long enough (very thin) fibre optic infeasibly large? Do the ice sheets move too much to prevent cable breakage? Do RTGs not put out enough heat to melt through the ice?

RTGs currently put out enough heat to melt the ice. The nice thing about RTG is that is you need more heat you just bring more nuclear material. You can find the right amount to melt a path for your probe in a reasonable amount of time. In essence you would pump water past a heat exchanger and direct it downward where it melts more ice. The probe would descend in a bubble of self created liquid water. The formerly liquid water above the probe would eventually freeze solid. So you would have a slowly descending bubble of liquid water in an otherwise solid block of ice.

Communication is the big challenge. Any trailing fiber optic cable would be in solid ice very quickly. The ice does move sometimes meters a day so designing a cable and deployment system that would allow your "landline" to survive would be a challenge.

Even if you solved communication we are probably at least two decades away from any such mission. NASA funding and the lack of detailed information on Europa being the major obstacles.

That and we are dropping a dirty bomb on a place we think might have life.

RTGs aren't really that harmful unless you damage them and it takes a lot to damage them. We dropped one into the ocean from orbital velocities (was carried aboard Apollo13) and it was expected to remain intact.

BTW: 3.9 kg of plutonium slightly used available. Possible collector's item as it orbited the moon. Must pick up at Tonga Trench. Bring own transportation.

I was also thinking that even if the material remains contained for the useful life of the mission, it will also have to remain contained for as long as the fuel is radioactive and dangerous. I don't know how long that is, but will the device be able to contain the radioactive material in an unpredictable alien environment that long?

 

[ralphnobody]

Plumes of water? Them there's Europan city trash, being dumped out at land.

 

[Statistical]

SmokeTest[/url]":4hxx7hxx]

jason8957[/url]":4hxx7hxx]

Statistical[/url]":4hxx7hxx]

SiberX[/url]":4hxx7hxx]Whenever discussion about probes on Europa comes up, I wonder about the feasibility of landing a two-part probe consisting of:

-A surface module, that does the initial landing and contains high-gain antennas to communicate with earth
-A submersible/penetrator module, heated and powered by RTGs to keep it at 70-80 celsius
-A long (5-10km) spool of fibre optic cable, held inside the sub and spooled out as the probe slowly melts its way through the icy crust

The whole assembly lands, and then the lander just plunks the warm sub module on the ice and lets it work its way down to the subsurface ocean. A few years later, there's a few km (hopefully they find a thin part of the crust to make it more manageable) of communication cable connecting the surface with the ocean, and your sub could then send data back to the surface for transmission. If you were clever enough you could even detatch the communication tether and roam deeper (returning to upload gathered data) but simply dangling under the tether cable might provide lots of useful data already.

Is such a plan possible? Is a long enough (very thin) fibre optic infeasibly large? Do the ice sheets move too much to prevent cable breakage? Do RTGs not put out enough heat to melt through the ice?

RTGs currently put out enough heat to melt the ice. The nice thing about RTG is that is you need more heat you just bring more nuclear material. You can find the right amount to melt a path for your probe in a reasonable amount of time. In essence you would pump water past a heat exchanger and direct it downward where it melts more ice. The probe would descend in a bubble of self created liquid water. The formerly liquid water above the probe would eventually freeze solid. So you would have a slowly descending bubble of liquid water in an otherwise solid block of ice.

Communication is the big challenge. Any trailing fiber optic cable would be in solid ice very quickly. The ice does move sometimes meters a day so designing a cable and deployment system that would allow your "landline" to survive would be a challenge.

Even if you solved communication we are probably at least two decades away from any such mission. NASA funding and the lack of detailed information on Europa being the major obstacles.

That and we are dropping a dirty bomb on a place we think might have life.

The real problem with RTGs is actually a lot more mundane, and something nobody has brought up yet. Namely, we don't have the materials to build any.

RTGs rely on plutonium to generate heat and power. Plutonium does not occur naturally in the universe except at trace levels. So all plutonium we have is manufactured in nuclear reactors. Back in 1988 the United States shut down plutonium production, and didn't reactivate it until recently, though production is limited to a handful of grams per year (scaling up is hard).

Limitations on nuclear technology designed to curb nuclear weapons programs also made it very difficult to produce plutonium for peaceful purposes. So, after 1988, basically all the plutonium we got came from Russia, and is of low quality (why would they sell the good stuff?). We have 35kg left, of which half has decayed so much that it's no longer useful for RTGs. The ~17kg left is essentially all already claimed.

NASA claims they aren't limited by plutonium, but this is at best misleading. It's a bit like saying you have enough materials to finish your work because you'll stop working once you run out. Similarly, NASA would be planning far more ambitious, and frequent, missions if they had more plutonium. For example, there was the proposed Jupiter Europa Orbiter mission, which was scrapped in favor of a more economical mission. Probably because the Jupiter Europa Orbiter mission would have required more plutonium than there currently exists on the planet in any form.

TL;DR: Earth is out of plutonium, and we don't know when we'll have more. Any plans predicated upon easy access to large amounts of plutonium are non-starters for at least a few decades.

Agreed with everything else you said but one correction, Pu-238, the isotope used in RTGs has no weapon application. In fact it undergoes spontaneous fission which makes it a very dangerous in nuclear devices. It makes weapon development risky even in trace amounts for the very obvious reason that the words "spontaneous fission" and "nuclear device" should bring to mind. We intentionally "cultivate" our weapons grade plutonium to ensure a very very low % of Pu-238.

We stopped making Pu-238 because well it is very expensive to make, only has one real purpose, and honestly isn't really associated with any other commercial or weapon material production. The only "economical" method to produce Pu-238 is to neutron bombard neptunium-237 (Np-237). So it means isotope separation of spent fuel to get nearly pure Np-237 blocks. Then transfer those blocks to a research reactor where the Np-237 will be transmuted into Pu-238 by capturing a neutron. You need a pretty high neutron flux because the short half life of Pu-238 means as soon as you start making it, a portion is decaying off. Then you remove the blocks, do another isotope separation to separate the useful Pu-238 from the Np-237 until you get high purity Pu-238. Now you either use it or lose it because it will decay in output continually. So you kinda need to project future needs against production

 

[Statistical]

jason8957[/url]":lex6xjx1]

Statistical[/url]":lex6xjx1]

jason8957[/url]":lex6xjx1]

Statistical[/url]":lex6xjx1]

SiberX[/url]":lex6xjx1]Whenever discussion about probes on Europa comes up, I wonder about the feasibility of landing a two-part probe consisting of:

-A surface module, that does the initial landing and contains high-gain antennas to communicate with earth
-A submersible/penetrator module, heated and powered by RTGs to keep it at 70-80 celsius
-A long (5-10km) spool of fibre optic cable, held inside the sub and spooled out as the probe slowly melts its way through the icy crust

The whole assembly lands, and then the lander just plunks the warm sub module on the ice and lets it work its way down to the subsurface ocean. A few years later, there's a few km (hopefully they find a thin part of the crust to make it more manageable) of communication cable connecting the surface with the ocean, and your sub could then send data back to the surface for transmission. If you were clever enough you could even detatch the communication tether and roam deeper (returning to upload gathered data) but simply dangling under the tether cable might provide lots of useful data already.

Is such a plan possible? Is a long enough (very thin) fibre optic infeasibly large? Do the ice sheets move too much to prevent cable breakage? Do RTGs not put out enough heat to melt through the ice?

RTGs currently put out enough heat to melt the ice. The nice thing about RTG is that is you need more heat you just bring more nuclear material. You can find the right amount to melt a path for your probe in a reasonable amount of time. In essence you would pump water past a heat exchanger and direct it downward where it melts more ice. The probe would descend in a bubble of self created liquid water. The formerly liquid water above the probe would eventually freeze solid. So you would have a slowly descending bubble of liquid water in an otherwise solid block of ice.

Communication is the big challenge. Any trailing fiber optic cable would be in solid ice very quickly. The ice does move sometimes meters a day so designing a cable and deployment system that would allow your "landline" to survive would be a challenge.

Even if you solved communication we are probably at least two decades away from any such mission. NASA funding and the lack of detailed information on Europa being the major obstacles.

That and we are dropping a dirty bomb on a place we think might have life.

RTGs aren't really that harmful unless you damage them and it takes a lot to damage them. We dropped one into the ocean from orbital velocities (was carried aboard Apollo13) and it was expected to remain intact.

BTW: 3.9 kg of plutonium slightly used available. Possible collector's item as it orbited the moon. Must pick up at Tonga Trench. Bring own transportation.

I was also thinking that even if the material remains contained for the useful life of the mission, it will also have to remain contained for as long as the fuel is radioactive and dangerous. I don't know how long that is, but will the device be able to contain the radioactive material in an unpredictable alien environment that long?

There is natural background radiation everywhere in the universe. Pu-238 decays relatively quickly to U-234 (one reason why it is so useful for RTGs). U-234 is a "natural" isotope of Uranium. I am fairly certain there is some Uranium on Europa. In fact if there is none that would be quite the mystery.

 

[NomadUK]

For this reason astrobiologists rank Europa at the top, or near the top, of places in the Solar System (aside from Earth) where extant life might exist.

If extant life doesn't exist, we've got a bit of a problem.