Page 1 of 2 12 LastLast
Results 1 to 30 of 40

Thread: If they send a probe to Europa, how will they get throught the ice?

  1. #1
    Join Date
    Dec 2004
    Location
    UK
    Posts
    8,053

    If they send a probe to Europa, how will they get throught the ice?

    I was thinking some sort of energy source like a battery could heat the head of a probe, and slowly melt and sink a shaft, trailing a communication cable behind it as the water refroze behind it...?

    Is this how they might do it, or is there another option?
    Formerly Frog march..............

    “One is never alone with a rubber duck.” The Golgafrinchan Ark B captain

  2. #2
    Join Date
    Feb 2016
    Posts
    1,526
    Yeah, scrape up stuff on the surface at one of the fissures. The material comes from inside, winds up outside, and we don't have to bore or expose the inside to our hitchhiking bugs.

  3. #3
    Join Date
    Dec 2004
    Location
    UK
    Posts
    8,053
    I just thought it might be simpler to design a mission so it could land nearly anywhere, and sink a shaft. Maybe a problem might be if the sinking probe came across rocks....

    Scraping off stuff sounds like it would add complexity, and extra machinery.
    Formerly Frog march..............

    “One is never alone with a rubber duck.” The Golgafrinchan Ark B captain

  4. #4
    Join Date
    Sep 2003
    Location
    The beautiful north coast (Ohio)
    Posts
    46,283
    I'm pretty sure we've had the discussion before, I just couldn't find a thread with that exact discussion. The two idea I believe are either melt or drill.

    Some related Europa threads:

    Europa Clipper mission (orbiter with possible lander)

    Discussion on how to get evidence of life without drilling
    At night the stars put on a show for free (Carole King)

    All moderation in purple - The rules

  5. #5
    Join Date
    Dec 2016
    Posts
    201
    Quote Originally Posted by Mudskipper View Post
    I was thinking some sort of energy source like a battery could heat the head of a probe, and slowly melt and sink a shaft, trailing a communication cable behind it as the water refroze behind it...?

    Is this how they might do it, or is there another option?
    Melting or drilling a hole all the way through doesn't seem plausible. The ice is estimated to be 15-25 KM thick. How about going through one of the plumes instead? Guess it might be a little hard to travel against the flow of water not to mention possible high pressure. I'm not convinced a plume would mean there's a crack all the way to the oceans below.
    Last edited by DaCaptain; 2017-Sep-23 at 02:52 PM.
    I know that I know nothing, so I question everything. - Socrates/Descartes

  6. #6
    Join Date
    Feb 2016
    Posts
    1,526
    The material under the ice comes to the surface with the plumes. This isn't rocket science.

  7. #7
    Join Date
    Sep 2003
    Location
    The beautiful north coast (Ohio)
    Posts
    46,283
    Quote Originally Posted by DaCaptain View Post
    Melting or drilling a hole all the way through doesn't seem plausible. The ice is estimated to be 15-25 KM thick. How going through one of the plumes instead? Guess it might be a little hard to travel against the flow of water not to mention possible high pressure. I'm not convinced a plume would mean there's a crack all the way to the oceans below.
    I wouldn't say it was impossible, but we are a long way from being able to do so. Heck, we couldn't do it on the surface of the Earth. The closest was the Russian work to sample Lake Vostok in the Antarctica and that was 4 km.

    I suspect we are at least 3 or 4 generations of space missions away from even thinking about doing such a thing. The Europa Clipper project is in the planning stages and will be an orbiter (sample plumes?) and a possible lander (surface samples only). ESA was thinking about a follow-up mission with a lander with a drill, but the drill would only go down maybe a meter or so, to collect "cleaner" samples.

    The orbiter might be able to investigate the idea of sampling plumes at the surface (looking for such active sites).

    I suspect we would exhaust all of that before we attempted a deeper probe, and given the timeline for such things, I suspect we are looking at decades before there might be such an attempt.

    I vaguely recall someone having an idea of a nuclear heated melter that would slowly melt through the ice, dragging a communications cable in back of it (the borehole would refreeze behind it) till it got down to the ocean, but I don't recall either details or feasibility.
    At night the stars put on a show for free (Carole King)

    All moderation in purple - The rules

  8. #8
    Join Date
    Sep 2003
    Posts
    11,735
    Quote Originally Posted by Swift View Post
    The orbiter might be able to investigate the idea of sampling plumes at the surface (looking for such active sites).
    That makes sense. Just guessing, but perhaps the bottom of the ice layer serves as a potential substrate for life. If so, wouldn't a geyser flush the adjacent floating organisms, or minnows, to the surface? Could an Earth-type fish out-swim the geyser flow?
    We know time flies, we just can't see its wings.

  9. #9
    Join Date
    Feb 2006
    Posts
    320
    The deepest oil well supposedly goes down more than 40,000 ft (~ 8 miles or ~ 12 km). Of course, drilling it involved people to handle the problems. Another argument for sending people to Jupiter, perhaps?
    Selden

  10. #10
    Join Date
    Sep 2003
    Location
    The beautiful north coast (Ohio)
    Posts
    46,283
    Quote Originally Posted by George View Post
    That makes sense. Just guessing, but perhaps the bottom of the ice layer serves as a potential substrate for life. If so, wouldn't a geyser flush the adjacent floating organisms, or minnows, to the surface? Could an Earth-type fish out-swim the geyser flow?
    The ideas I've read about sampling either surface, near-surface (the meter or so down layer), or plumes would not be looking for fish, or even I think microorganisms, but for chemical signatures of life.
    At night the stars put on a show for free (Carole King)

    All moderation in purple - The rules

  11. #11
    Join Date
    Sep 2003
    Posts
    11,735
    Quote Originally Posted by Swift View Post
    The ideas I've read about sampling either surface, near-surface (the meter or so down layer), or plumes would not be looking for fish, or even I think microorganisms, but for chemical signatures of life.
    I was being a bit hyperbolic as that would be an extreme scenario. But if we are searching for life and if the lower ice serves as a substrate (assumption) for microorganisms, which would invite larger critters (assumption) to feed upon it, would there be any reason why these things wouldn't get shot out of the geyser?
    We know time flies, we just can't see its wings.

  12. #12
    Join Date
    Apr 2007
    Location
    Nowhere (middle)
    Posts
    34,567
    The very first Europa surface probe will, I think, have to stick to analyzing small ice cores. We're just not there yet by a long shot.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  13. #13
    Join Date
    Jun 2007
    Posts
    5,462
    Quote Originally Posted by Swift View Post
    I wouldn't say it was impossible, but we are a long way from being able to do so. Heck, we couldn't do it on the surface of the Earth. The closest was the Russian work to sample Lake Vostok in the Antarctica and that was 4 km.

    I suspect we are at least 3 or 4 generations of space missions away from even thinking about doing such a thing. The Europa Clipper project is in the planning stages and will be an orbiter (sample plumes?) and a possible lander (surface samples only). ESA was thinking about a follow-up mission with a lander with a drill, but the drill would only go down maybe a meter or so, to collect "cleaner" samples.

    The orbiter might be able to investigate the idea of sampling plumes at the surface (looking for such active sites).

    I suspect we would exhaust all of that before we attempted a deeper probe, and given the timeline for such things, I suspect we are looking at decades before there might be such an attempt.

    I vaguely recall someone having an idea of a nuclear heated melter that would slowly melt through the ice, dragging a communications cable in back of it (the borehole would refreeze behind it) till it got down to the ocean, but I don't recall either details or feasibility.
    Lake Vostok is in a much higher gravity field. Pressure increases with depth much more slowly on Europa, so approaches such as an RTG-heated "mole" can go much deeper. The main issue with going all the way through to the ocean is carrying enough cable to keep an antenna on the surface...that's a lot of cable, and it has to be reasonably resilient against things like collapsing tunnel sides or fractures in cooling re-frozen ice.

    The problem with just looking at surface material is that Europa's surface is subjected to intense radiation. Any electronic equipment left on the surface will have a short lifetime, and any complex organic molecules that were brought to the surface have long ago been degraded beyond recognition. However, going just a few tens of meters deep would vastly improve the quality of the samples and allow much longer-lived probes.

  14. #14
    Join Date
    Feb 2016
    Posts
    1,526
    Pity the ESA/NASA people won't think to shield their probe. And of course they won't sent it to a recent eruption, any old spot will do.

  15. #15
    Join Date
    Jun 2007
    Posts
    5,462
    Quote Originally Posted by Noisy Rhysling View Post
    Pity the ESA/NASA people won't think to shield their probe. And of course they won't sent it to a recent eruption, any old spot will do.
    Radiation shielding is heavy and landers have even tighter mass budgets than orbiters. Europa orbits within Jupiter's radiation belts, and likely the only solid-surfaced body in the solar system with a worse radiation environment is Io. The Juno probe has its electronics in a "vault" shielded with 1 cm of titanium and avoids the main concentrations of the radiation belts, and is still only good for a few dozen orbits. With feasible amounts of shielding, a Europa surface probe would only last around 20-40 days. This is a big part of the reason they aren't planning to use RTGs for surface probes, primary batteries can do the job for as long as the electronics are expected to last.

    And no, they won't just "send it to a recent eruption". Their primary criteria for a landing site is going to be that the probe can survive the landing and get a signal back to the orbiter. This is not likely to be compatible with ongoing surface-refreshing cryovolcanism, if that even exists...all we've observed so far is vapor plumes.

  16. #16
    Join Date
    Feb 2016
    Posts
    1,526
    I think they'll work something out before they go. It's not rocket science.

    Oh, wait...

    As for the eruptions, how about one that stopped erupting yesterday? And what's wrong with vapor plumes?

  17. #17
    Join Date
    Oct 2017
    Location
    Voronezh, Russia
    Posts
    13
    Radiation level on the surface of Europa - 5,4 Sv per day. It's around lethal dose for human, but not a big deal for radiation-hardened electronics like that, which can withstand 185 day on the surface of Europa without radiation shielding (may be a little bit less, because some dose he take when travel from Earth to Europa - it's take several years travel in interplanetary space).

  18. #18
    Join Date
    Dec 2016
    Posts
    201
    So any guesses how long it'll take to melt through the ice?
    I know that I know nothing, so I question everything. - Socrates/Descartes

  19. #19
    Join Date
    Feb 2016
    Posts
    1,526
    Quote Originally Posted by DaCaptain View Post
    So any guesses how long it'll take to melt through the ice?
    How thick is the ice? Do we really want to do that?

  20. #20
    Join Date
    Oct 2017
    Location
    Voronezh, Russia
    Posts
    13
    Quote Originally Posted by DaCaptain View Post
    So any guesses how long it'll take to melt through the ice?
    I'll take for example RTG from Cassini probe - he have 33 kg plutonium-238, which produce 17,82 kW heat (0.54 watts per gram) and have diameter 0,422 m. Then we need to do a hole in 10 km deep, what means we need melt 5595 cubic meters water ice (5129 ton) with start temperature about −160 °C. With ice enthalpy of fusion 333 J/g and ice heat capacity 2,05 J (per gram per kelvin) it's take a 661 kJ to melt 1 kg ice (37 second with RTG power), but for melt all ice - it's take around 6 years.

    Not fast! But we can use bigger RTG with smaller area and reduce time to less than one year. And by the way - the probe will be fine, because after he melt first hundred meters of ice, the water above it will protect probe from radiation on surface.

  21. #21
    Join Date
    Oct 2017
    Location
    Voronezh, Russia
    Posts
    13
    Quote Originally Posted by Noisy Rhysling View Post
    How thick is the ice? Do we really want to do that?
    1) Thickness around 10-30 km, and of course at the beginning we have to choose a place thinner. 2) Yes, of couse - this is one of the last places where we can find life in Solar system (along with Ganymede, Callisto and maybe a Triton).

  22. #22
    Join Date
    Feb 2016
    Posts
    1,526
    I asked at Physics Forum:

    Related to exploration of Europa: If we elect to send a probe to bore through (guessimate) five kilometers of ice to reach the Covered Seas, and have a diameter of 100 mm and length of one meter, how much energy will the probe require to reach unfrozen areas? AND given that figure, is it currently feasible to build a probe that will have an energy supply to do the boring without supply from the surface? (I assume a line connected to the surface so the probe can report results, but not a power line. Note that the comm line will have to be heated so as to prevent freeze lock and allow the probe to proceed.)

    I'm quite willing to expand on the information provided so far, as best I can.
    Yesterday at 10:23 AM #2
    JRMichler
    JRMichler
    13 / 7
    Diameter 4" times 16,400 feet time 57 lbs/ft^3 = 81,600 lbs of ice to melt. That's a theoretical minimum, the actual would be somewhat higher.

    Assume surface temperature -300 deg F, temperature at liquid boundary 32 deg F, and linear variation in between. Then the average ice temperature is -134 deg F. Average specific heat of ice is about half that of water, so (32 - (-134)) X 0.5 BTU / lb-deg F + 144 BTU / lb = 227 BTU/lb to heat the ice to 32 degrees and melt it.

    227 BTU/lb X 81,600 lbs / 3412 BTU/kwh = 5400 kwh. That's a theoretical minimum that assumes zero heat loss into surrounding ice. The actual requirement would be at least twice that much. Battery power is not possible. Even 5 km long power cables may not be possible, given that the ice will refreeze behind the probe. It might be possible to melt the ice and pump it up to the surface. That would require an insulated heated tube 5 km long and a pump capable of 950 PSI.
    I think we'll need some dilithium crystals.

  23. #23
    Join Date
    Oct 2017
    Location
    Voronezh, Russia
    Posts
    13
    Quote Originally Posted by Noisy Rhysling View Post
    I asked at Physics Forum:

    I think we'll need some dilithium crystals.
    Energy production by chemical batterys is not enough - it's true. But for that we have nuclear power (like RTG) and we don't need to have power cables and pumps actually - when probe melting ice it will by descend under the influence of gravity and water above him will be freeze (and seale the cable on the ice) this will happen by itself. We need only tiny data cable for transmitting station on the surface. Probe must withstand pressure of 10+ km ice about him, but on such depth immersed even manned boats. I didn't consider the loss on heating of the external ice - but even with worst case, it's take around 12 years to melt all ice, and plutonium-238 gives us 87,7 years to reduce heat production in two times - quite enough to go trough the ice.

  24. #24
    Join Date
    Jul 2005
    Location
    Massachusetts, USA
    Posts
    21,634
    I think it would be helpful to have some kind of surface mission with at least three landers first to be able to measure the seismic activity of Europa. This could help with better guessing the thickness of the ice, but more importantly, if some eventual ice-melting probe is leaving a wire up to a surface platform, having the wire sheared by a quake would be hard to recover from.
    Forming opinions as we speak

  25. #25
    Join Date
    Feb 2016
    Posts
    1,526
    Quote Originally Posted by antoniseb View Post
    I think it would be helpful to have some kind of surface mission with at least three landers first to be able to measure the seismic activity of Europa. This could help with better guessing the thickness of the ice, but more importantly, if some eventual ice-melting probe is leaving a wire up to a surface platform, having the wire sheared by a quake would be hard to recover from.
    If we did a lander why couldn't we just drive up to a geyser or upwelling and take samples? Fresh from the liquid part, no drilling required. No chance of contamination. If we give it the Opportunity it might just show some Spirit.

  26. #26
    Join Date
    May 2013
    Location
    Central Virginia
    Posts
    1,266
    I agree with Noisy, drilling through miles of ice to reach the liquid level is several accidents waiting to happen. Keeping it simple will surely end up as the solution we seek.

  27. #27
    Join Date
    Feb 2016
    Posts
    1,526
    Quote Originally Posted by Spacedude View Post
    I agree with Noisy, drilling through miles of ice to reach the liquid level is several accidents waiting to happen. Keeping it simple will surely end up as the solution we seek.
    We know that cold germs survived a long stay on the Moon. And that was on a piece of gear that was built in a clean-room. If we can build a probe that can be irradiated at currently insane levels to kill all the unintended passengers it might be okay to probe under the ice. Until then please don't risk it.

  28. #28
    Join Date
    May 2008
    Location
    The Netherlands
    Posts
    14,021
    Quote Originally Posted by Noisy Rhysling View Post
    If we did a lander why couldn't we just drive up to a geyser or upwelling and take samples? Fresh from the liquid part, no drilling required. No chance of contamination. If we give it the Opportunity it might just show some Spirit.
    No need to drive up, just land where there are "erupted materials" to be found. Probably not surprising, NASA has thought about that option too. See for example the Europa Lander Study 2016 Report (PDF, 264 pages)

    ETA: Or search NASA Technical Report Server NTRS for cryobot and find us some gems to read.
    ____________
    "Dumb all over, a little ugly on the side." -- Frank Zappa
    "Your right to hold an opinion is not being contested. Your expectation that it be taken seriously is." -- Jason Thompson
    "This is really very simple, but unfortunately it's very complicated." -- publius

    Moderator comments in this color | Get moderator attention using the lower left icon:
    Recommended reading: Forum Rules * Forum FAQs * Conspiracy Theory Advice * Alternate Theory Advocates Advice

  29. #29
    Join Date
    Feb 2016
    Posts
    1,526
    Quote Originally Posted by slang View Post
    No need to drive up, just land where there are "erupted materials" to be found. Probably not surprising, NASA has thought about that option too. See for example the Europa Lander Study 2016 Report (PDF, 264 pages)
    But if the bot is mobile it can sample more than one vent.

    Do the vent erupt like Old Faithful, on schedule? I don't know.

  30. #30
    Join Date
    Oct 2017
    Location
    Voronezh, Russia
    Posts
    13
    Quote Originally Posted by Noisy Rhysling View Post
    If we did a lander why couldn't we just drive up to a geyser or upwelling and take samples? Fresh from the liquid part, no drilling required. No chance of contamination. If we give it the Opportunity it might just show some Spirit.
    Orbital probe "Europa clipper" under development, launch planning in the 2020s. He will have the opportunity to fly through water plumes and analize them (like a Cassini do in "suicide flyby" 25 km from Enceladus, measuring the suitability for the life of his ocean). Melting the ice - it's a next step. Space probes for studing Europa and Ganimede propose NASA, ESA, JAXA and even Roscosmos - but every without success unfortunatly. Maybe all together we can do this?

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •