NASA Releases Details of Titan Submarine Concept 119
Zothecula writes: Now that NASA has got the hang of planetary rovers, the space agency is looking at sending submarines into space around the year 2040. At the recent 2015 NASA Institute for Advanced Concepts Symposium, NASA scientists and engineers presented a study of the Titan Submarine Phase I Conceptual Design (PDF), which outlines a possible mission to Saturn's largest moon, Titan, where the unmanned submersible would explore the seas of liquid hydrocarbons at the Titanian poles.
"At its heart, the submarine would use a 1 kW radiothermal Stirling generator. This would not only provide power to propel the craft, but it would also keep the electronics from freezing. Unfortunately, Titan is so cold that it's almost a cryogenic environment, so the waste heat from the generator would cause the liquids around it to boil and this would need be taken into account when designing the sub to minimize interference. However, NASA estimates that the boat could do about one meter per second (3.6 km/h, 2.2 mph)."
"At its heart, the submarine would use a 1 kW radiothermal Stirling generator. This would not only provide power to propel the craft, but it would also keep the electronics from freezing. Unfortunately, Titan is so cold that it's almost a cryogenic environment, so the waste heat from the generator would cause the liquids around it to boil and this would need be taken into account when designing the sub to minimize interference. However, NASA estimates that the boat could do about one meter per second (3.6 km/h, 2.2 mph)."
25 Years from now? (Score:3)
At least they will all be fusion powered by then.
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Or just send a 3D printer to Titan and send the files for the new technology as we invent it!
Re:25 Years from now? (Score:5, Interesting)
You joke, but the ability to reconfigure spacecraft on the fly even on the smaller scale has proven itself valuable time and time again. I love how they came up with a trick after New Horizons was launched to nearly double its communication rate. It has two radio transmitters, one primary and one backup, and one dish. When they launched, it seemed obvious that only one could be used at a time - but en route someone figured out that if you have one transmit with right-handed polarization and the other with left-handed, they can both transmit at the same time, and then on Earth the two signals can be separated out. But since the spacecraft wasn't designed for enough power to use them at once (that was never supposed to be necessary), they needed to find a trick to get more power. And it's not easy, given that there's not a lot of things running when the probe is just drifting in deep space - what are you going to do, shut down your guidance computer? Well... yes, that's exactly what they came up with - when they've filled up their memory, they align the antenna, then spin up the spacecraft, shut down the guidance computer, transmit at double speed until the memory is free, then restart guidance and stop the spin so that they can resume data collection.
While 3d printing and robotic arms for assembly is a stretch at present, the importance of having hardware flexibility is increasingly being demonstrated in space missions.
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Actually, this proposal envisions being powered by a Stirling engine powered by radioisotopes (considerably more efficient than a RTG), and NASA recently canceled its support for flight tests of Stirling engines powered by radioisotopes.
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Hmmmm.... is someone trying to get funding for their pet research perhaps?
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And what would be wrong with that?
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Plus it finally gets us away from falling victim to one of the classic blunders, "Never get involved in a land war in Asia."
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But there wouldn't be anyone to waterboard.
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Get Al Gore to fund exploration. (Score:1)
Get Al Gore to fund exploration. Then he can pay the "hydrocarbon tax" for the whole place.
Liquid hydrocarbons, you say? (Score:5, Funny)
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I agree. Add some weapons now. Also, it should probably be designed like a marine creature to avoid suspicion from any possible alien marine life. You know what this means, right?
Robotic Shark with frickin' lasers!
Re:Drop it on Europa (Score:5, Informative)
What you're describing is an incredibly challenging tasks. One needs several missions to get to better know Europa in general, and specific potential entry areas in particular, first. These missions are going to be expensive and have long lead times. And an actual boring / submersible mission is going to be extremely expensive.
Titan has one main strike against its exploration, that it's so dang far away. But almost everything else about it is tailor-made for exploration. It's ideal for aerocapture. It's trivial to stay aloft, at an altitude of your choice, be it by hot air or lifting gas balloon, blimp (likewise), helicopter, fixed-wing aircraft, tilt-wing aircraft, etc. Low temperatures pose some difficulties but can be nice for electronics, and the rate of heat loss (even in a hot air balloon concept) is so low at such low temperatures that you don't need very big heat sources. The hydrocarbon seas are permanently exposed for whatever means of exploration (aerial, boat, submarine) you choose. Ascent requirements (sample return, for example) are surprisingly low versus a body of that size due to the ability to fly so high in the significant pressure / low gravity environment before needing to fire rockets. And so forth. And there's so darn much we don't know about Titan, perhaps even more than Europa. There's constant complex organic chemistry going on in the upper atmosphere of which we know almost nothing, and probably even some on the surface [nasa.gov]. There's probable liquid water under the surface and cryovolcanoes [usgs.gov] that erupt it to the surface. There's earthlike weathering processes done with/to completely different materials, and the entire gas cycle is a giant mystery right now. So yes, I'm pretty excited about whatever mission goes to Titan next.
Too bad the next launch window to Saturn (2018, 4,13km/s delta-V, 8,2 years) is simply not going to happen. : There's not going to be such a low delta-V/time window for a long time - 2020 is 5,18 km/s / 11,0y; 2021 is 4,80km/s / 8,8y; 2024 is 4,81km/s / 10,4y; etc. So if we're lucky maybe we could get the 2021 window (though the increased delta-V reqs would significantly hurt the payload)... otherwise, there won't be a spacecraft getting to Saturn before the mid 2030s. :
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And speaking of liquid water under the surface, has anyone else noticed how almost every body in space that people point a camera at long enough seems to have evidence of "unexpectedly large" amounts of heat under its surface, esp. at surprisingly shallow depths? I really want to know what it is that people are overlooking because it keeps happening again and again, people expect to see dead rocks drifting through space and find out that they're still surprisingly alive with some process or another that mea
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Except that it always seems to be in excess of what they calculate. It's just one "there's more heat than we expected' after the next... one kind of begins to wonder if they need to figure out why their expectations always seem to be wrong.
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I'm not just talking about Europa. I'm talking Enceladus and half a dozen other moons that were thought to be most assuredly dead but turned out to have liquid water geysers, for example. I'm talking about the unexpected internal heat in our moon. I'm talking about Titan's apparent level of internal activity in excess of predictions. I'm talking about how Io's volcanoes are in the wrong spot based on what we know about how it should be heating. I'm talking about how there's even considered 50-50 odds right
Re:Drop it on Europa (Score:5, Interesting)
Hmm, just another thought which I haven't seen anywhere else. Orbital velocity through Titan's ionosphere would be about 1500 m/s, if my calculations are right. Exhaust velocity on ion engines ranges from tens of thousands to millions of meters per second. So a ram scoop to refill propellant is plausible, your drag should be well less than your ability to reboost with the propellant you acquire, even if efficiency is low; in practice you should be able to capture much faster than your burn rate. While all ion engines have certain elements which are "optimal" in terms of performance, you can generally use whatever ions you want without too dramatic of a sacrifice in terms of isp and thrust (so long as there's no corrosion problems or the like).
So, for a sample return mission:
1) A probe with detachable, flying lander (each RTG-powered) is boosted to LEO. As for the lander, I personally like the tilt-wing design, as it allows easy of landing and requires only a small RTG (it can fly in short hops, replenishing batteries on the ground while during surface science), but allows the high speed and range of travel of a fixed-wing plane.
2) The probe begins a decade or more ion-propelled journey to Saturn, with only enough propellant to reach a stable orbit in Titan's upper atmosphere (and possibly some minor exploration of the Saturnian system en-route).
3) The lander drops off, aerobrakes over the course of a few weeks, and then explores the planet for a year or so while the orbiter replenishes itself. A tilt-wing aircraft could probably explore all of the most interesting places on the planet in that timeframe and take numerous small samples). The lander only needs a small antenna, as the orbiter can act as a repeater to Earth.
4) When exploration and propellant refill are done, the lander then flies back up through the atmosphere to as high and fast as it can, then activates a rocket stage (1500-2000 m/s delta-V) to re-rendezvous with the probe. The spent stage is ejected.
5) The probe returns to Earth on ion power using its propellant from Titan (possibly with some minor exploration of the Saturnian system en-route). Upon return to Earth, the leftover propellant could itself be studied as a sample return in its own right (it could even be gathered into different tanks from different altitudes via an elliptical orbit if so desired).
Re: Drop it on Europa (Score:1)
I always thought that with cryogenic temperatures we could use superconductors and something along the lines of the Meisner effect (as long as a source of magnetic field lines exists) for propulsion.
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What you're describing is an incredibly challenging tasks. One needs several missions to get to better know Europa in general, and specific potential entry areas in particular, first. These missions are going to be expensive and have long lead times. And an actual boring / submersible mission is going to be extremely expensive.
What!?! Next you'll be talking us that even with Apollo levels of funding and political commitment, it'll take us at least 30 years to put a person on Mars.
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I'm confused, and you seem to know something or another. why would the rate of heat loss be low? titan is extremely cold, and heat loss goes as the gradient of the temperature correct? Or are you saying there are obvious choices of gas which have very high levels of thermal expansion at those temperatures to make it that the temperature gradient isn't very large?
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Most of what I've read about heat loss on Titan pertains to hot air balloons, so I'll cover that first.
Thermal radiation is proportional to the temperature to the fourth power. So essentially zero. Convective / conductive losses are proportional to the gas density, surface area, and to the absolute difference in temperature. Buoyancy is relative to the relative gas densities, meaning for a given amount of buoyancy in Titan, you're dealing with only a small absolute temperature difference compared to what's
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Too bad the next launch window to Saturn (2018, 4,13km/s delta-V, 8,2 years) is simply not going to happen. : There's not going to be such a low delta-V/time window for a long time - 2020 is 5,18 km/s / 11,0y; 2021 is 4,80km/s / 8,8y; 2024 is 4,81km/s / 10,4y; etc. So if we're lucky maybe we could get the 2021 window (though the increased delta-V reqs would significantly hurt the payload)... otherwise, there won't be a spacecraft getting to Saturn before the mid 2030s. :
I think you're looking at launch windows waaaaaay to close to present.
There is no way that NASA, at its current funding level, is going to design, build, and test a nuclear-powered submarine for an interplanetary mission in 3-5 years.
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Honestly, I can't think of a more compelling place outside of Earth that we have current, compelling evidence that there is life or lifelike processes ongoing than Titan.
A long mystery on Titan has been, where is the methane coming from? We can see it being converted into the atmosphere into a wide range of organic compounds, various compounds of CHON (the building blocks of life, one might add), and the whole atmosphere should be converted in about 50 million years - yet here's this multi-billion-year-old
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The freezing point of methane is -182C so there's not a big spread between freezing and melting.
Apparently, methane with dissolved nitrogen has a wider spread between freezing and boiling, but I don't know how much it helps.
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Liberal Senator: If this is a space mission, wouldn't this involve rockets? According to my latest Quinnipiac, 43% of my constituency now supports that trendy new anti-fire movement, and I'm up for reeleection next year. No thanks.
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Due to the large amount of data that needs to sent to Earth, the submarine needs a large dorsal fin that includes a planar phased-array antenna. While operating, the submarine would surface for 16 hours per day for Earth communications during which it would study its surroundings using a mast camera.
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Note : A Titan day is 15.94 Earth days
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Probably they would do it in a manner similar to how they do it with conventional submarines: occasionally surfacing and transmitting normally, or else releasing a buoy with communications capabilities.
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If the properties of longer-chain hydrocarbons apply to that of supercooled liquid short-chain hydrocarbons, then it should be pretty transparent to RF. That said, if it was a problem, the solution is as simple as "surface".
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No science fiction future here (Score:2)
TIL: I will likely be dead before the planets of our solar system are widely investigated. The time necessary to plan and execute an interplanetary mission is daunting.
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The time is largely spent in political wrangling and procurement. Once people figure out how to make money with space flight (and that will happen), things will go much more quickly.
Private companies are probably going to be reluctant to invest significantly in space flight until property rights have been worked out. No point in spending billions on mining an asteroid only to have people tell you that you don't own it, on top of an already very risky operation.
The Asteroid Redirect Mission [nasa.gov] might be the most
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Not if we can get a few more private billionaires interested in the subject. After Anousheh Ansari will come the multitudes.
NIAC != NASA (Score:2)
NASA Institute for Advanced Concepts is a way of giving relatively small amounts of money ($100,000) to outside researchers to begin to flesh out advanced ideas. One hundred K is not going to buy you a fully designed Titan submarine. So, this is a idea, but not much more, and may have little or even no resemblance to NASA thinking, NASA plans or anything that is actually done later.
NUMA? (Score:2)
Consider Man's Footprint (Score:2)
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Way ahead of you.
http://planetaryprotection.nas... [nasa.gov]
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1 kW radiothermal Stirling generator. (Score:2)
At its heart, the submarine would use a 1 kW radiothermal Stirling generator.
In other words, an impobability drive. Beware of the whales.
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I must say, I kind of had the same reaction.
Because it seems like every time someone mentions a Stirling generator it's to say "it's not a perpetual motion machine".
I've never really been clear on what they're for or if people actually use them for real world stuff.
Re:1 kW radiothermal Stirling generator. (Score:4, Informative)
For the love of $DEITY how about doing a cursory search before ranting?
http://en.wikipedia.org/wiki/A... [wikipedia.org]
Yes it's used. Yes even for space applications. No it have nothing to do with perpetual motion machines...
steam rocket (Score:2)
Seems like you ought to be able to do better in terms of propulsion when you can easily vaporize the liquid you're immersed in.
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Perhaps the difference is that much of the ship on Titan would be operating at temperatures close to the phase transition, whereas on Earth only a tiny part of the ship is operating at such temperatures.
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We're not.
You mean like steam jet marine engines that have been in and out of the news for the last 15 years? The advantages of them were supposed to be much higher reliability than impeller based jet engines and that ability to run off of waste heat from either a generator or another propulsion method, and extremely compact, simple construction (no moving parts). Last I heard issues were mainly with scaling it up, although people have built versions for RC sized boats. It certainly would be a lot easier if you we
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Ah yes, mercury as a structural material...
https://en.wikipedia.org/wiki/... [wikipedia.org]
One of my favorite hard sci-fi novels. Cheesy as all hell, and just a platform for Hogan to tilt at this favorite strawmen, but fun.
Message from Dave/HAL 9000/??? (Score:2)
All these worlds
are yours except
Europa
attempt no
landing there
Titan's Crust (Score:1)
Doesn't Titan have a solid crust of ice like 1 or a few kilometers thick? A submersible rover is a super cool idea, but first you have to get it to the ocean. I'm confident they can figure out how to get something to Titan, but getting it through the ice to the ocean is something else entirely. A drill seems expensive from a weight and fuel standpoint, and an explosive would have to be nuclear in size to crack it and cause all sorts of problems.
Or am I confused; are the oceans exposed?
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They're talking about the exposed hydrocarbon seas. They're mainly confined to the poles. The largest, Kraken Mare, is larger than the Caspian Sea, though is only believed to be about a tenth as deep. There's still some question as to whether the surfaces freezes, and if so, whether it's for how long. For any frost to float it would have to contain nitrogen bubbles. Some very small waves are believed to have been observed.
Exactly what makes them up, their source, how they behave, etc is all quite speculati
Real question.... (Score:2)
"The exact blend of hydrocarbons in the lakes is unknown. " - Real question is can you set it on fire?
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Your answer is contained in the answer to this question: is there an oxidizer in that mix?
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How can that be a question?
Do you know about an hydrocarbon that does not burn?
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How can that be a question? Do you know about an hydrocarbon that does not burn?
In Titan's atmosphere hydrocarbons will not burn.
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Obviously not ... another no brainer ;)
The view is wrong. (Score:2)
On Titan the view of Saturn is edge-on to the rings as Titan is in the ring plane. So the rings of Saturn would not be visible in the sky.
Seeing the artists get this wrong in the 2009 Star Trek movie is a bit forgiving, as they need to impress their audience. But on Gizmag?!? I would have expected better.
why Titan? send it to Europa (Score:2)
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How do you know that Europa's subsurface water seas aren't sterile and that Titan's subsurface water seas don't have little fishies?
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There's also a lot of water on Titan, so again, your point? Titan is one of two bodies in the solar system (the other being Europa) where there's a high degree of confidence that there's a global subsurface ocean deep enough to fully decouple the crust from the mantle / core. The subsurface tides on Titan are so strong that the whole mercury-sized moon buckles 10 meters depending on where it is in its orbit.
So again, why the obsession with Europa and
Release (the sub into) the Kraken (Score:2)
I'm sure the name tickles those who obsessively play Kerbal Space Program... not that I do... or know people who do... (hides his drawings of SSTO designs).
Cool concept. Let's hope it comes to fruition.
Give me a ping, Vasili...
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What a waste (Score:2)
We could use that technology to explore the Earth's oceans and exploit, if needed, methane hydrates.
Sky Of Orange (Score:4, Funny)
"Sky Of Orange".
And sea of polyethyline.
"Sea of polyethyline".
In our Titan
"In our Titan".
Submarine
"Submarine"
Boiling water? (Score:2)
How should a 1kW thermal exhaust get the water boiling around a submarine in an 'infinite' big water reservoir is beyond me.
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Imagine a red hot piece of iron from a blacksmith, and he puts it in a lake. Water boils around the iron, not the whole lake.
Plus it's not water.
Plus it's at a very, very low atmospheric pressure.
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Yeah, I noticed later it is supposed to get into a hydrocarbon lake.
Regarding your hot red iron ... the probe won't be that way :) thats the point.
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Why should we imagine that?
Because the report summary mentions cavitation issues. You can only spread the waste heat (which is more than 1 kW, that is the electrical power) so much trying to balance insulation to keep instrumentation warm enough while have low enough thermal insulation to still have a good cold sink for the sterling engine.
Think of the Big Picture. (Score:2)
If by any chance there are 'living creatures' of some type,
they will be remembering this as the "Great Death" (or something equivalent.)
A 1000w heater (the sub) in a big ocean of methane better have a Lot of surface area, if they want to avoid boiling it. :)
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It's not water. It's mostly liquid methane.
The moon (Score:2)
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Life? (Score:2)
Attack On Titan! (Score:2)
"...the waste heat from the generator would cause the liquids around it to boil..."
Because there is nothing like studying marine life by boiling it... My only question is will they equip the submersible with a garlic butter sauce or not, because without it, I don't see it being a worthwhile endeavor.