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#76 2004-03-20 21:55:45

GCNRevenger
Member
From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Europa

If you are going to live on Europa, you have to do somthing about the ungodly amount of radiation... the easiest thing to do would be to live UNDER the ice.


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#77 2004-03-20 22:05:12

Palomar
Member
From: USA
Registered: 2002-05-30
Posts: 9,734

Re: Europa

On another note, one potential drawback to using a tether for data is if Europa has any ongoing ice plate fault shifting due to tidal or other causes (as seems likely) and the tether happened to be across a fault it would get snapped, although its probably not that great a risk considering all the other risks involved...

*This brings to mind another question.  I suppose it might be impossible to calculate, but how fast might the waters of Europa be traveling (flowing/circulating)?  I recall how quickly water flows beneath iced-over rivers; basically at the same rate of speed as when it's all completely free-flowing.  But I suppose there might be a difference as compared to oceanic flows; I have no idea, I'm not very familiar with these particulars.

Just curious.

--Cindy


We all know those Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...

--John Sladek (The New Apocrypha)

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#78 2004-03-22 12:11:34

SBird
Member
Registered: 2004-03-10
Posts: 490

Re: Europa

Interesting question.  I have no idea but the molten water on Europa is nost likely created by the massive tidal forces created by Jupiter.  On one hand, you have large tidal forces which could move a lot of water around but I'm not sure if this could create actual oceanic currents.  Also, since the heating is so evenly distributed, it might not allow for the generation of temperature-gradiant driven currents to the extent as on Earth.

I just read somewhere (I can't remember the URL, sorry) that recent analysis of Galileo spectral data from Europa shows that the surface is highly acidic.  The estimate was that there was a sufficient amount of sulfuric acid to have a pH of close to 0.  The article went on to say that this might make the interior of Europa hostile to life.  Personally, I'm hoping that this is just an effect of sulfur ions from Io that have accumulated on the surface.  If the interior of Europa is similarly acidic, the chances of finding organic life are approximately 0.

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#79 2004-03-23 14:36:12

Palomar
Member
From: USA
Registered: 2002-05-30
Posts: 9,734

Re: Europa

I just read somewhere (I can't remember the URL, sorry) that recent analysis of Galileo spectral data from Europa shows that the surface is highly acidic.  The estimate was that there was a sufficient amount of sulfuric acid to have a pH of close to 0.  The article went on to say that this might make the interior of Europa hostile to life.  Personally, I'm hoping that this is just an effect of sulfur ions from Io that have accumulated on the surface.  If the interior of Europa is similarly acidic, the chances of finding organic life are approximately 0.

*::sigh::

Even if it's discovered Europa has no life prior to a probe being sent, it'd still be great to burrow within and scope it out.  I imagine vast tunnels and caves, perhaps even icy stalactites and stalagmites...

Here's a cool site: 

sea salts or battery acid??   Yipes!

--Cindy


We all know those Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...

--John Sladek (The New Apocrypha)

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#80 2004-03-23 20:51:02

Mad Grad Student
Member
From: Phoenix, Arizona, North Americ
Registered: 2003-11-09
Posts: 498
Website

Re: Europa

I just read somewhere (I can't remember the URL, sorry) that recent analysis of Galileo spectral data from Europa shows that the surface is highly acidic.  The estimate was that there was a sufficient amount of sulfuric acid to have a pH of close to 0.  The article went on to say that this might make the interior of Europa hostile to life.  Personally, I'm hoping that this is just an effect of sulfur ions from Io that have accumulated on the surface.  If the interior of Europa is similarly acidic, the chances of finding organic life are approximately 0.

First, I'll touch on the controlling the hydrobot issue. Of course, the most obvious way to do it, what first appears in people's minds, is to snake a control cable down with the probe. I did the calculations and in order to give the probe 20 miles of tether (10 to reach the ocean, 10 to play around with) you'd need 2.53 cubic meters of cable, provided it was only 5 millimeters in diameter. Did I do something wrong here, that sounds pretty small? After all, that would fit in a cylinder one meter in diameter by 3.2 meters in length. A cord that thin would probably be possible in the future with miniturization technology.

Of course, there are other problems with that method as well. For example, as the cryobot bored through the ice the pack would refrezee behind it, and since ice expands as it frezees this could snap the tether. Additionally, earhquakes (Or perhaps europaquakes   :;): ) could possibly cut the cord as well.

ELF radio soundds like a nice idea at first, but there are some serious problems with it. For example, since each crest ELF waves have a wavelength of over 20 feet, it would take a long time to transmit data. In fact, it takes submarines hours just to transmit a few lines of binary text, imagine how long even a low resolution image would take! Drilling up to the surfaces faces the problems such as the length of time and energy it would take, and weither the probe surfaced in the right spot. A small distance under the icecap could translate into miles of distance on the surface!

One possibility I thought of is perhaps using a form of rapid-pulsing sonar to transmit data. Upon landing, the lander would put an extremely sensative seismometer on the surface, learn the average frequencies of the europaquakes, and tune them out. The cryobot would have a very powerful sonar gun operating at a very artificial-sounding frequency, easily distinguished from natural sounds. Using the sonar, the cryobot would pulse on and off at about 1,000 pulses per second. At that rate, it would still take almost 17 minutes to fax a very low-res picture, but that's better than nothing.

As for the issue about Europa's acidity, I don't think we have to worry about that getting in the way fo life. It would take lots of sulfuric acid, as in an 80% solution,to create a Ph near 0, more likely it would be around 3. Even if the ocean were very acidic, that wouldn't be much of a problem. There are forms of bacteria here on Earth that live in water in the hotsprings at Yellowstone that's just about the same in acidity as sulfuric acid. Bacteria can live anywhere, provided they actually develop. As Ian Malcom put it, life will find a way.   cool


A mind is like a parachute- it works best when open.

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#81 2004-03-24 15:43:58

SBird
Member
Registered: 2004-03-10
Posts: 490

Re: Europa

When I came up with my cable mass estimate, I figured on a 0.5 mm cable which is a bit small.  I'd say that arealistic value is on the order of maybe 1-2 mm in diameter.  If you're just running a fiber optic line down the center, the cable can be quite miniscule.  There could also be provisions for slippage joints that could allow for expansion of the ice without loss of the cable. 

The sonar is a cool idea.  I'm not sure if it's possible to get enough power to get a sonar ping through ice.  I seem to recall that submarine sonar does poorly around ice pack but that might be broken ice pack with lots of ambient white noise. I'd say that sonar is a good backup communication system along with ELF.  (Also, doesn't ELF require ahuge antenna?) 

Sulfuric acid is more worrisome than the pH might indicate.  Sulfuric acid is particularly effective at destroying organic materials through dehydration.  Try adding concentrated H2SO4 to sugar sometime to see.  If there's anything like a 1M concentration f sulfuric acid, carbon based life as we know it is impossible.  It's easy to see things like acid resistant bacteria and assume that life can grow anywhere but this is a fallacy.  No living organism on this planet has been recorded at temperatures above 121C or living in the absence of water.  That already rules out most of the solar system right there.  In terms of planetary conditions, life, even extremophile life is startlingly delicate.

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#82 2004-03-24 15:57:16

atomoid
Member
From: Santa Cruz, CA
Registered: 2004-02-13
Posts: 252

Re: Europa

Thanks for all the engineering analysis.

On another note, how could the probe do any imaging. Its dark as pitch below that ice, perhaps they could take some pictures of the bottom of the icepak with the help of a light close up, and this is likely to be a prime place to search for organics and life. They might also be able to use imaging to get a profile of the level of particulates suspended in the water.

But to get a picture of the subsurface, it would seem that theyd have to use some very sensitive infrared that could detect the temp differences on the subsurface, such as geothermal (Europathermal?) venting areas. I dont really know anything about this stufff, but might differential temperatures in the water (updrafts) tend to make any such images pretty blurry? (which i guess would be pretty good data in itself anyway)


"I think it would be a good idea". - Mahatma Gandhi, when asked what he thought of Western civilization.

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#83 2004-03-25 15:08:12

SBird
Member
Registered: 2004-03-10
Posts: 490

Re: Europa

I suspect high resolution sonar would be used for wide area photos and that a flash camera would be used for close-up shots of things of interest.

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#84 2004-03-25 15:28:09

Palomar
Member
From: USA
Registered: 2002-05-30
Posts: 9,734

Re: Europa

On another note, how could the probe do any imaging. Its dark as pitch below that ice, perhaps they could take some pictures of the bottom of the icepak with the help of a light close up, and this is likely to be a prime place to search for organics and life. They might also be able to use imaging to get a profile of the level of particulates suspended in the water.

But to get a picture of the subsurface, it would seem that theyd have to use some very sensitive infrared that could detect the temp differences on the subsurface, such as geothermal (Europathermal?) venting areas. I dont really know anything about this stufff, but might differential temperatures in the water (updrafts) tend to make any such images pretty blurry? (which i guess would be pretty good data in itself anyway)

*Pardon my likely nutty idea, but what about night vision technology?  I'm not that familiar with it, and I thought I'd heard that it relies on -heat- to help image stuff.  If there are pockets of extra warm water or "smokers" or whatever, maybe that would help the probe to see (if outfitted with night vision technology).  I'm really out of my element here!!  Just a suggestion.  :-\

--Cindy


We all know those Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...

--John Sladek (The New Apocrypha)

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#85 2004-03-25 16:59:17

SBird
Member
Registered: 2004-03-10
Posts: 490

Re: Europa

There's 2 kinds of night vision technology.  The most common one is light amplification - it takes the low levels of light present at night and amplifies it so that you can see.   This doesn't work in complete darkness like Europa's oceans since there's no light to amplify. (or shouldn't be - maybe you could use the natives' casino neon signs for a light source)

The other is less used because it's a bit bulky - IR imaging.  This looks at heat radiation.  However, the problem is that you need heat sources to see anything.  Since everything in the ocean is going to be about the same temperature, you won't be able to amke anything out in IR other than what the average temperature is.  Hot sea vents and living organisms will show up very well but overall sonar is the best means of seeing underwater.

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#86 2004-03-25 17:15:21

Julius Caeser
Member
From: Malta
Registered: 2004-03-25
Posts: 105

Re: Europa

I believe there is already evidence gathered from Galileo orbital data about europathermal underwater activity.Looking at pics of the few craters on the europan surface reveals the crust   not to be uniformly thick as some craters are better preserved than others .In places where the crust is thicker ,that is where the underlying water is colder,craters are more lunar like in morphology.Other places where the crust is thinner.the impacting projectiles seem to have reached the underlying water or slush layer leaving a ghostly crater or ripple effect on the surface.Thin crust may be overlying areas of europathermal activity.These areas should be the sites where future robotic Europa landers should be directed to do any digging underground!  Sorry if this subject   has been tackled in the past,I'm new here..glad to be here thou!!!                     big_smile

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#87 2004-03-25 20:12:33

Mad Grad Student
Member
From: Phoenix, Arizona, North Americ
Registered: 2003-11-09
Posts: 498
Website

Re: Europa

It's easy to see things like acid resistant bacteria and assume that life can grow anywhere but this is a fallacy.  No living organism on this planet has been recorded at temperatures above 121C or living in the absence of water.  That already rules out most of the solar system right there.  In terms of planetary conditions, life, even extremophile life is startlingly delicate.

Yes, this is true, of course, I didn't mean that lfe can evolve ANYWHERE, just many, many more palces than we once thought. For example, huge colonies of live bacteria have been found inside nuclear reactors, that's over boiling temperature and under extreme radiation. I've read before (But don't know the accuracy of this) that live bacteria spores were found on pieces of one of the surveyors that was returned by Apollo 12. Granted, they were just spores, but that's still something highly advanced on the scale of solar system astrobiology. At one time it was thought that no life could exist without the sun's warming rays, but look at geothermal vents. Life doesn't just exist there, it thrives, and in very alien forms.

The best argument I've heard yet against life on Europa is the fact that the moon is constantly bombarded by oxygen ions off of Jupiter's magnetic field. Today, virtually all life depends on oxygen for some reason just to survive, but back when it was all getting started oxygen was an increadiblly dangerous and toxic substance. Remeber that oxygen is very good at breaking down organic compounds due to its reactivity, which is the primary cause of aging. yikes  So, if you want to stay young forever, don't breathe! tongue

I'm sure that bacteria could find away to get around high sulfuric acid concentrations if they worked the problem for a whilie. Of course, there's no guarentee that there is life on Europa, just a good opportunity of it happening. Astrobiologists are a bit like Cubs and Red Sox fans, rooting for the underdog that requires a bit of faith just to believe in, but eternally hopeful that this will be "next year." 
:;):


A mind is like a parachute- it works best when open.

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#88 2004-05-26 10:17:08

Yang Liwei Rocket
Member
Registered: 2004-03-03
Posts: 993

Re: Europa

http://www.johnstonsarchive.net/astro/images/jupeur.jpg

i always liked this picture of europa, mankind has done great things in space and NASA's rover project is wonderful. maybe some day soon we will land a probe on it like we have done on Mars


'first steps are not for cheap, think about it...
did China build a great Wall in a day ?' ( Y L R newmars forum member )

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#89 2004-05-26 10:57:34

Palomar
Member
From: USA
Registered: 2002-05-30
Posts: 9,734

Re: Europa

http://www.johnstonsarchive.net/astro/images/jupeur.jpg

i always liked this picture of europa, mankind has done great things in space and NASA's rover project is wonderful. maybe some day soon we will land a probe on it like we have done on Mars

*It wouldn't download for me...will try again (my computer's been a bit whacked lately).

Yes!  I would love to see a probe on Europa.  SBird has made some very interesting posts in that regard (a month or so ago).

And since the subject came up again, I was searching Google the other day for information (speculation) as to the size of Europa's possible ocean(s), how many "pockets" of water it might contain, i.e. as **if honeycombed** by pockets of water or what...etc.  I somehow doubt the water, if it exists, wraps around the entire planet, between the ice and whatever crusty material covers the core.  But of course that's just my speculation; a "cut-away" diagram of Europa I've seen at a Solar System web site doesn't speculate on the possible water factor.  It's just a "cut-away" as if Europa is completely solid.

--Cindy  smile


We all know those Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...

--John Sladek (The New Apocrypha)

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#90 2004-05-26 17:30:33

RobS
Member
From: South Bend, IN
Registered: 2002-01-15
Posts: 1,701
Website

Re: Europa

As I understand it, Cindy, the scientists think Europa has a planetwide layer of liquid water, rather like a zone in the crust or mantle. The ocean is ubiquitous and potentially quite deep, 100 km or so.

What worries me is the method of getting through the crust: melting. What if the cryobot melted down through 50 meters of ice and encountered a chunk of nickel-iron from an old impact twenty meters in diameter? That would be the end of the effort.

        -- RobS

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#91 2004-05-27 09:33:42

REB
Member
From: Houston, Texas
Registered: 2004-04-07
Posts: 555
Website

Re: Europa

Rob, I thought of that too. If the probe hit a rock, it needs a way to get around it.

Perhaps if it had some kind of radar to detect objects in its path it could adjust its course as needed.

The best thing to do is to find where the ice crust is the thinnest. There may even be some places were it is very thin.


"Run for it? Running's not a plan! Running's what you do, once a plan fails!"  -Earl Bassett

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#92 2004-05-28 06:42:42

Palomar
Member
From: USA
Registered: 2002-05-30
Posts: 9,734

Re: Europa

What worries me is the method of getting through the crust: melting. What if the cryobot melted down through 50 meters of ice and encountered a chunk of nickel-iron from an old impact twenty meters in diameter? That would be the end of the effort.

        -- RobS

*Hi Rob and REB:  Thanks. 

Yeah, anything's possible.  But you know Europa has what is considered one of the *smoothest* surfaces in the entire Solar System.  It'd make pre-invasive interior rock hunting interesting, to say the least (zero to very few craters).  Contrast to Callisto, its Galilean sibling, the most heavily cratered moon in the Solar System.  :laugh:  How do such extremes exist in so close an area?

But yes, interesting speculation.  I wonder if most meteors just don't bounce off that thick, dense shell of ice...or maybe Europa is somehow out of a major meteor zone (and Callisto is in it).

Hurry up, JIMO! 

I wish SBird would chime in on your comments, Rob.

--Cindy


We all know those Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...

--John Sladek (The New Apocrypha)

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#93 2004-05-31 04:55:40

atomoid
Member
From: Santa Cruz, CA
Registered: 2004-02-13
Posts: 252

Re: Europa

Contrast to Callisto, its Galilean sibling, the most heavily cratered moon in the Solar System.  :laugh:  How do such extremes exist in so close an area?

I think the theory was that Callisto hasnt had anything change its terrain since it was formed, so the craters are all built up on top of each other from time immemorable, whereas Europa's surface, being a layer of ice on its sea, is somewhat plastic and is always relatively young, since any crater impacts are assimilated and disappear over a relatively short timescale.

Callisto would be a good place to drill and get good core samples chronicling the last few billion years.


"I think it would be a good idea". - Mahatma Gandhi, when asked what he thought of Western civilization.

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#94 2004-06-25 06:01:30

Palomar
Member
From: USA
Registered: 2002-05-30
Posts: 9,734

Re: Europa

Folding Europa

*An "oldie but a goodie" from Astropix.  This image from the late Galileo probe, taken in 1998.  Terrific detail -- ridges and "freckles" of little craters (maybe they should be called "indentations" instead, since they also are very smooth in appearance).  wink

--Cindy


We all know those Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...

--John Sladek (The New Apocrypha)

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#95 2004-06-25 17:22:37

atomoid
Member
From: Santa Cruz, CA
Registered: 2004-02-13
Posts: 252

Re: Europa

Folding Europa

*An "oldie but a goodie" from Astropix.  This image from the late Galileo probe, taken in 1998.  Terrific detail -- ridges and "freckles" of little craters (maybe they should be called "indentations" instead, since they also are very smooth in appearance).  wink

--Cindy

awwww shux! the link times out... broken or just down for now?


"I think it would be a good idea". - Mahatma Gandhi, when asked what he thought of Western civilization.

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#96 2004-06-25 18:08:47

Palomar
Member
From: USA
Registered: 2002-05-30
Posts: 9,734

Re: Europa

Folding Europa

*An "oldie but a goodie" from Astropix.  This image from the late Galileo probe, taken in 1998.  Terrific detail -- ridges and "freckles" of little craters (maybe they should be called "indentations" instead, since they also are very smooth in appearance).  wink

--Cindy

awwww shux! the link times out... broken or just down for now?

*What happened??  yikes  The link was working fine when I checked it after posting.  Now all of Astropix seems "down."

Here's the actual address of the photo and caption:

http://antwrp.gsfc.nasa.gov/apod/ap000825.html

I've never known of Astropix (aka "Astronomy Picture of the Day") being completely inaccessible.  :hm:

Hopefully will be back up ASAP.

--Cindy

::EDIT::  Sunday, June 27 -- Astropix accessible again and link is working  smile


We all know those Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...

--John Sladek (The New Apocrypha)

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#97 2005-02-20 09:27:23

Yang Liwei Rocket
Member
Registered: 2004-03-03
Posts: 993

Re: Europa

JIMO was to be NASA's first nuclear-powered mission

sad

but its launch date has already slipped from 2011 to 2015


http://www.nature.com/news/2005/050124/ … 3342a.html

Jupiter Icy Moons Orbiter, a high-priority mission to look for saltwater oceans, and perhaps life, beneath the ice that covers the Jovian moons Europa, Ganymede and Callisto.
Delayed once by NASA's decision to power it with a nuclear reactor being developed to power manned bases on the moon and Mars - it has been slowed again by a decision to move the reactor experiment to an earlier mission.

Overall, NASA's 2006 budget estimate shows steady growth through 2010 for space science programs related to robotic and human exploration of the solar system. But the money for astrophysics, for studies of the solar environment and climate change are flat.
"There has been a concrete and very specific decision that the top priority is solar system exploration and that anything that doesn't contribute to that gets lower priorities," says John Logsdon, a space historian at George Washington University.
Some liken what is emerging from the Bush administration to the centrally planned economies that ultimately fail to raise a nation's standard of living.

www.baltimoresun.com

Cut Project Prometheus / JIMO
they are to include no funding for the Jupiter Icy Moons Orbiter (JIMO) mission in its FY2006 budget proposal, effectively killing the program ?


'first steps are not for cheap, think about it...
did China build a great Wall in a day ?' ( Y L R newmars forum member )

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#98 2005-03-15 02:32:23

Yang Liwei Rocket
Member
Registered: 2004-03-03
Posts: 993

Re: Europa

will the Euros support the USA's Europa mission in Space ?
next big cooperative European-US space mission will be to Europa, the ice-crusted moon of Jupiter ?

See the BBC news

A joint working team is being set up to consider what sort of spacecraft would be needed and what each side could do.

Officials in Washington and Paris are keen to follow up the spectacular success of Cassini-Huygens at Saturn.

"It was a beautiful marriage and we really are looking to do a repeat," said Professor David Southwood, from the European Space Agency (Esa).


Another joint co-operative mission like Ulysses, the Hubble and Cassini-Huygens ?


'first steps are not for cheap, think about it...
did China build a great Wall in a day ?' ( Y L R newmars forum member )

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#99 2005-03-15 06:30:33

Palomar
Member
From: USA
Registered: 2002-05-30
Posts: 9,734

Re: Europa

will the Euros support the USA's Europa mission in Space ?
next big cooperative European-US space mission will be to Europa, the ice-crusted moon of Jupiter ?

See the BBC news

A joint working team is being set up to consider what sort of spacecraft would be needed and what each side could do.

*That would be wonderful!  Yep, both sides have proven that the team-work WORKS.  cool

I certainly hope to see a spacecraft visit to Europa, including a (safe!) lander on its surface, in my lifetime.  And the knowledge of whether or not life exists beneath that icy crust.

--Cindy


We all know those Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...

--John Sladek (The New Apocrypha)

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#100 2005-03-15 12:37:03

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 19,690

Re: Europa

What they need from the US is the RTG power generation source that was in mind for JIMO. Is there any technology barriers that would not allow for this to occur?

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