You're mistaken. The main reason desal plants consume so much energy in pumping is not due to sea level changes, it's to provide sufficient osmotic pressure for the membranes. Freshwater is in a higher energy state than saltwater, and that energy must be provided in some way or another. In the brine desalination system, it's provided by the sun evaporating seawater to brine. In a conventional osmotic system it's electricity running pumps.
Sunlight is free**. Electricity is one of the most expensive forms of energy commonly used by humans.
** - Apart from your capturing system. But the beauty part here is how incredibly cheap the capture system is vs. how much solar energy it captures.
And that's folks is why being an arse when you disagree with someone is usually mutually exclusive with being able to write proper English.
The flames in a house fire can of course be "over a thousand degrees F". Most air in a burning house is below the boiling point of water. But hey, let's just assume that your bucket is sitting right on top of the ignition source of your house and somehow remains directly in flames underneath it for half an hour. Gee, what sort of analogy could we have for a large metal pot-like thing sitting on some gas stove-like flames... oh yeah, how about a pot sitting on a gas stove (whose flames can also be "over a thousand degrees F")? Because anyone who's ever put a large pot full of water on the stove (for example for canning) can tell you that it will NOT boil off in half an hour.
And seriously, a steel bucket will be "gone"? Methinks you need to look up the melting point of steel.
Or for something cheaper, M-Disc in a bucket of water. Water shouldn't get significantly over boiling in a fire (as it loses its heat by boiling off), and M-Disc is rated to withstand boiling water and not degrade from long-term water immersion (they're burned not by modifying a photosensitive dye like in normal discs, but by literally etching a hard, inorganic layer)
*I'm* saying that when people and businesses are struggling to get water, and there's *one* industry out there that's only a tiny portion of the economy that's making everyone else suffer, then it's a situation that ought to be remedied.
Let's just take this at face value, and let's falsely pretend that the water shortages aren't also causing cutbacks by residential consumers. Then that's 40% of the state's water to provide a fraction of 2% of the GDP, in drought conditions.
Even in your scenario, do you think this is appropriate?
I wonder if they could help increase the economic picture via value-added product recovery from the discharge brine. The oceans have an interesting mix of dissolved minerals and there's already interest in recovery of a number of them; perhaps the concentration of the discharge brine could help improve their economics a bit.
(of course, what I find a more interesting possibility for recovery is mining the pacific garbage patch for minerals that have over the course of years soaked up into the plastic from the seawater)
Agriculture is the big culprit, taking 80% of the state's water (and in return ag and mining together only make up 2% of the economy). Its a totally unsustainable situation that has to be remedied sooner or later.
That said, I do have hope for the future of desalination. Not with current techs (as with the one in the article, they're energy hungry and expensive), but potentially with new techs that don't rely on electricity as their power source. One I find interesting is this one. Basically, it relies on evaporation, which isn't unique... but *not* by capturing the evaporated water. It's just concentrated salt solution that's desired, which means that you don't need some sort of elaborate vapor capture system and sealed tanks, just simply any sort of open area that can hold water - even an endoherric basin or jettied-off chunk of ocean. Far, far cheaper.
Concentrated brine is turned into freshwater via ion bridges: it's connected to two tanks of normal seawater, one by a positive ion bridge and the other by a negative ion bridge. The brine greatly wants to dilute into the normal seawater, but it can't because the ions would be imbalanced in the two side tanks. So these two side tanks are connected to a third tank of seawater with the opposite ion bridges, so that salt can dilute from the brine into the two seawater tanks, but only if they also "suck" the opposite ion out of the final seawater tank. Since the brine concentrated brine wants to dilute so much, the action is energetically favorable and continues until there's no salt left in the third tank - aka, it's freshwater. (An actual implementation would be a continuous process, not fixed tanks, of course)
Apart from basic pumping needs, there's no electricity needed. The energy source is just "sun falling on any water chunk of seawater that's not free to circulate with the open ocean". You might even be able to have it filled automatically in some places via the tides or waves breaking over a jetty without having to pump new seawater in, leaving the only pumping needs for distribution.
Of course, the main tech limitation right now is making the salt bridges have high enough throughput and reliability to justify the capital costs.
Your first example sounds weird, and the second is unambiguously not valid English. Neither express exactly the same sense of action as the example. And the sentence I gave was just one example out of countless. Word genders are just word groupings which help reduce sentence ambiguity. You can detach them from the concept of a human gender; you could call them wizzlewozzles, it makes no difference. They just reuse the pronouns from actual gendered beings, which saves some linguistic space.
Also, the concept that one has to learn a gender for each word... first off, in most languages with genders, there's patterns for recognizing what words are what gender. They're not always universal, of course (in an ideal language they would be simple and universal), but they're important. Secondly, there's all sorts of data a person has to learn about each word to be able to speak properly as it is. Even if you have to learn a gender for each word, patterns aside, it's just a tiny piece in a much larger puzzle - that puzzle being reliably and concisely transmitting information across a noisy connection.
With three genders in Icelandic, the odds of a collision between an arbitrary two is only one in three. As you might say, "good enough for government work". Languages are never, and can never be "perfect", there's always tradeoffs on how you allocate space. But I have to say, your example of how to do it in English was a pretty bad tradeoff (having to repeat "the backhoe")
Unfortunately, from the air you can't actually do a whole lot more than from low orbit.
The whole point of "from the air" is that you can land. And take off and land and take off again and again. It's not exactly tricky to raise or lower altitude.;) And on Titan, low gravity plus a dense atmosphere yields very low terminal velocities, i.e. cushy landings without much effort. But even if you're not talking about landing, you absolutely can do a lot more by virtue of being able to get so much closer to the surface. Much of science is about resolution.
Meanwhile, Titan is MUCH colder Mars, at around 94K average surface temperature, whereas Mars' average is about 218K . Building equipment to operate reliably in those temperatures starts to get difficult.
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The issue isn't average temperatures. The issue is temperature ranges. Having to tolerate a single very cold temperature is far easier then having to tolerate temperatures that range from very cold to very hot. The biggest challenge for Huygens wasn't tolerating the cold of Titan, it was tolerating the cold of Titan *and* the solar heat from flying near Venus.
The average day-night temperature on Mars is a 100K difference. Seasons add another 45 on top of that. This repeated thermal cycling incredibly stressful on all of a rover's systems. It also mandates a much more complex thermal management system. For example, Curiosity uses a system of computer controlled pumps to pump a cooling fluid from its RTG either to the probe internals or to the radiators based on the ambient temperature. If it wasn't an actively managed heat flow it could overheat the probe in the summer or freeze the probe in the winter.
Remember, it was ultimately winter that killed Spirit. Had the temperature been steady, and Spirit been designed to handle that steady temperature, this would not have happened. When you have a very specific temperature envelope, it's just a situation of "insulate and add radiothermal heaters or heat output from the RTG wherever needed". It's a lot more complicated when it fluctuates.
And contrary to popular belief, it doesn't get harder to heat as the temperature gets colder, it actually gets easier - that is to say, the amount of energy needed to heat a craft to 300K in a 100K environment isn't dramatically higher than the amount of energy needed to heat it to 300K in a 200K environment, far less than double (the exact details depend on the situation). Radiative heat loss is proportional to the temperature to the fourth power, so it drops off to nearly nothing at low temperatures (we'll just ignore for now that on Titan you're also not exchanging heat with the vacuum of space, rather the upper atmosphere). Convection on Titan is also greatly slowed. That's why the calculations show that you can heat a whole sizeable hot "air" blimp on Titan with just an RTG (that, and how much lift you get for how little effort!).
And as you point out, nuclear is really the only viable power source, which means you have to figure out how to dissipate waste heat without damaging the surrounding environment beyond your ability to learn anything.
Yet people use RTGs aplenty - even on Mars where it's possible to use solar. Almost half of successful actively-powered Mars surface probes have been RTG powered - the two Viking landers and Curiosity vs. Pathfinder, Spirit, Opportunity, and Phoenix. RTGs are more reliable, simpler, and provide useful heat. But they're also expensive, which is the main reason for the inner / outer solar system solar / RTG dichotomy that Mars straddles. A typical high power RTG may cost on the order of $100M. Not a big deal if it's a Flagship mission, maybe a big deal if it's a New Frontiers mission, and definitely a big deal if it's a Discovery mission. It'd be nice if a Sterling version could be finally developed, that'd be another big facilitator for outer planet missions by bringin
To the submitter: Okay, I'd start with saying, "don't reinvent the wheel more than necessary". So for example, consider IPA as the writing system. Or if you want to invent a writing system to be optimized by a given set of rules, at least consider using the IPA forms as your basis.
Consider who your target learners are. Is it the whole world? Any particular weighting that you want to apply with certain native tongues? Check and see what phonemes and linguistic rules are common in the languages by whatever weighting you want to apply.
When doing your weighting to decide what phonemes to use, don't only consider "whether the language has it", but also "how easy is ot for people to learn who don't know how to do it. For example, among the sounds in Icelandic that aren't in English there's the "ll" lateral plosive and the alveolar trill "r". The "ll" is nothing like anything found in English, yet given a simple description most English speakers can pronounce it perfectly. On the other hand, some people struggle for years and never manage to learn a trilled "r".
That is, all to say, an ideal language takes research not just on what phonemes people use, but what phonemes are easy to learn.
Then there's one of the biggest issues, which is intelligibility. You want the most diverse array of phonemes possible without being likely for the listener to confuse two similar ones together. Again, research would pay off big here.
The exact same rule applies to vocabulary / grammar, and this is unfortunately one thing that constructed languages usually suffer from relative to evolved ones. If English had the word "dog" like it is now, but the word for cat was "dawg" with only a slightly different pronunciation, these two common everyday words would lead to a lot of confusion. This normally gets steadily selected out either with pronunciation shifts or the adoption of alternative words.
If you really want to get into it, you could write an evolutionary algorithm to optimize your vocabulary and/or grammar to maximize the auditory difference between different common words and word phrases. The goal is to keep that signal to noise ratio up to maximize understandability.:)
One I'd recommend is something that Icelandic does: having a simple, universal stress rule. That is, the first syllable of every word, and the first part of every compound with at least one syllable between them, is stressed. And when I say stressed I mean literally double the length of the others. What this does is make it so that even a beginner can tell exactly where one word or part of word ends and the next begins.
A couple things that English speakers often attack about other languages you should think about instead of just readily dismissing them:
1. Genders. It seems archaic, right? But there are practical reasons. For example, consider the sentence:
"I used a backhoe to drag a box but it was ruined in the process"
Which is ruined, the backhoe or the box? In Icelandic it's obvious because a backhoe is feminine but a box is masculine. Sorting words into differing groups adds some clarity to sentences. It comes at the cost of increasing the amount of knowledge needed for each word (this is usually done by breaking words into patterns, such as "if it ends with these letters, it's in this group"). You could, for example, have such a grouping (calling it something other than gender), but have the rules for determining whether a thing is in a particular group be really obvious. Taking a direct from English example, if we wanted many groups, one for each last phoneme in the word, the above could become:
"I used a backhoe to drag a box but itoe was ruined in the process."
Now it's obvious to a "native" speaker of our constructed language that the particular word for "it" refers to the backhoe.
The other thing English speakers often complain about is declensions. But once again, they're another example of giving additional info
I didn't say "cracked into a million pieces"; it simply no longer had the structural integrity to stay in its slot in the door and my attempts to glue together in a manner that would restore its structural integrity without having it ending up looking hideous failed in both respects. It was still one piece though.
Even if a scanner could detect the cracks, it's not hard to picture the interface having a trivial "crack repair" filter. I'd expect it to be part of any basic package along with rust removal, scratch removal, corner wear repair, etc; it's not algorithmically complex by any means; the first is just vertex merging within a given radius, the second could take several forms, the third is a selective gaussian blur filter, the fourth is a selective sharpening filter, etc. Popular 3d editors like Blender already have functions that can do all of these sorts of stuff and more.
In many ways, Titan is an easier world than Mars (no question that Europa is the odd one out, we're nowhere close to being able to get a probe to explore its oceans). If it wasn't for the distance, it'd be far easier and safer. Lower gravity plus a nice thick atmosphere makes it so easy to aerobrake and gives you tons of great ways to get around (balloons, blimps, helicopters, fixed-wing aircraft, tilt-rotor craft, etc). Moving by air is not only orders of magnitude faster, but - so long as the air is stable, which it appears to be on Titan - safer, too. Surface rovers can and regularly do get stuck, and sometimes it's fatal. The low gravity and dense atmosphere helps with lots of other stuff too - for example, huygens was able to touch down just with a simple parachute, no retrorockets needed (touchdown is always a very nail-biting step in any Mars mission, there's so much that can go wrong with whichever approach you use, even with all of our experience). Plus on Titan there's little electrostatic blowing dust, your radiation levels are lower, your temperatures are more stable, etc
The distance of course is the one big pain with Titan, and it majorly affects a number of things - your delta-V reqs, your transit times, your communication bandwidth / power / weight tradeoffs, your launch windows, etc, and also mandates the use of nuclear power, where on Mars it's only one of two options. Ion engines are thankfully helping to "shrink" our solar system, but no question, the distance is a real big disadvantage for Titan vs. Mars.
But it's really the only major disadvantage. It's so easy to land and get around once you're there.
Humans can create new tools and are vastly more flexible in what they can do than any robot.
Okay, you're on Mars. You discover that there's a neat rock that the instruments you were sent with aren't good enough to completely. You could use some more data. Perhaps thermal conductivity? Okay, go ahead and make a thermal conductivity probe on Mars with enough accuracy to be useful. Maybe one possibility is sensitive to, say, hydrofluoric acid? Go ahead, make some hydrofluoric on Mars. Well, what about a streak or hardness test? Aha, a human could come up with a way to do that by using some other tools or other objects for purposes they weren't designed for! But you know what? So could a robot.
You might be able to come up with some edge case that a human could do that a robot couldn't. But "edge cases" don't pay for increasing the budget by orders of magnitude.
There is a huge difference between looking through a webcam at an ocean and actually standing at the shore yourself.
Unless you're talking about "gee whiz" factors, no. A proper payload can replicate your senses in far more accuracy in far less mass. Your eyes are cool and all, but their eyes can zoom, record readings at each spectral frequency, see IR and UV, see polarization, etc. Your sense of touch is cool and all, but theirs can get precise measurements of thermal conductivity, electrical conductivity, etc. Your sense of smell is neat and all, but versus a mass spectrometer? Just no. And on and on. You are not a scientific instrument. The only thing you really have going for you is your brain. And you know what? That works just fine here on Earth, regardless of how it gets its data.
There are economic benefits to developing the technology to send humans
The economic knock-on effects of building a bigger rocket to carry people, tons of supplies, radiation shielding, etc, versus instead using the same money to build dozens of diverse robots with all kinds of diverse scientific equipment? Absolutely no contest there that the latter will pay off better.
There are some things we will only learn if we are there ourselves.
Like, "Wow, that sure cost a DAMNED lot of money!"
What I really want to see is a single ambitious Titan mission that could answer nearly all of the questions we have today (while undoubtedly making tons of new ones... ah, the beauty of science;) ):
* The craft would consist of (beyond its initial boost) a propulsion/communication module, an exploration module, and an ascent module.
* The propulsion module would use its RTG power, plus the power from the RTG of the attached exploration module, to run the ion engine, draining its tank to near empty to get into a low Titan orbit through the ionosphere.
* The explorer and attached ascent module would be released, to slowly have their orbits decay to capture, while the propulsion module would remain in low orbit acting as a communications relay (thus keeping down the weight and power requirements for the explorer).
* During its time in orbit, the propulsion module would be acting as an electrostatic "scoop" through Titan's ionosphere. Its orbit being about 1500m/s but its exhaust velocity being tens to hundreds of thousands of meters per second, it should be able to scoop up gas to use as propellant without being overcome by drag (most ion engines are propellant flexible). Over the course of a year or so it should be able to fill up its tank.
* Apart from this feature, the propulsion stage (now an orbiter) is kept simple - for example, no radar or other power hungry, heavy scientific equipment.
* After a couple weeks of losing velocity and altitude, the explorer and ascent stage's orbit will fully decay. The explorer would be a tilt-rotor aircraft with pontoons. Autorotation of the props would slow down the stage during descent, and then active powered thrust at high throttle would reduce the landing velocity.
* The ascent stage, a couple hundred kilograms, would significantly outweigh the explorer, at a several dozen kilograms. The explorer would disconnect from it before roaming the planet, an activity which would be done as a series of daily hops: 1) The craft climbs straight up like a helicopter, then 2) tilts its wings forward to fly as an airplane, in order to get maximum range out of minimum power - a few hundred kilometers per flight. 3) It flies to the location decided the day before while collecting aerial imagery, then 4) does a vertical descent. 5) On the surface it rests for about a day while it does surface science, transmits data, and waits for the next day's instructions while its RTG recharges its flight batteries.
* Small samples (a few grams each) are collected from each location, whether solid or liquid, and individually chambered in a honeycomb-like storage bay.
* With that sort of range capability and about a year of exploration time, the probe could probably explore pretty much every major interesting feature on the planet (while identifying no shortage of future targets, no doubt).
* At the end of its mission it returns to the ascent stage and docks with it. If the probe is capable of lifting the ascent stage (most likely the best option), it achieves the maximum altitude and delta-V it is capable of with its flight batteries before firing the stage; the stage would thus require somewhere around 1,7k m/s delta-V. If the ascent stage has to be launched from the surface, then it needs an additional 0,5-1k.
* In orbit it moves to an intercept orbit with the now-full propulsion stage and ejects the ascent stage. The propulsion stage docks with it and begins spiraling away from Titan to an Earth-return trajectory using the combined power of the two RTGs.
* Any of several possible recovery methods are used at Earth to recover not just the sample pack from the explorer, but any residual propellant (aka, Titan's atmosphere) from the propulsion stage tanks. If the propulsion stage uses multiple tanks then different tanks could be filled from different areas of Titan's outer atmosphere.
Sample return and detailed imagery from every interesting portio
Good question. NASA seems to be on a search obsessively focused on the concept "liquid water touching bedrock equals life, anywhere without liquid water touching bedrock equals no life". There's so many things wrong with this concept I don't even know where to start. We don't even know if the first forms of life on our own planet developed that way, let alone whether it's common or rare and whether other possibilities are common or rare.
It bothers me because it causes them to obsess over certain bodies (Mars, Europa) while ignoring others. Personally, if I was hunting for life, of all the places in the solar system outside of Earth, I'd pick Titan (which usually gets ignored because it's so cold).
* It's bigger (although not heavier) than Mercury, and has a predominantly nitrogen atmosphere denser than Earth, with a full meteorological cycle.
* We know that there's complex organic chemistry going on en masse there. Today.
* We've detected dozens of types of complex organic chemicals already even with our limited study and we know we're only scratching the surface. Unidentified chemicals around 10000 daltons have been detected in the atmosphere. There's probably even more complex chemicals on the surface. There's so much complex organics there that it blankets the surface in places.
* There's not one type of liquid on Titan but multiple - an underground sea (which reaches the surface through cryovolcanoes, we're pretty certain) and surface seas of hydrocarbons of what appear to be significantly varying compositions.
* Titan's methane is regenerating itself. We don't know why. On Mars they treat the presence of unexpected methane as an incredible sign of possible life, on Titan it's treated just as a "Huh, weird" thing
* Before the details of what was going on on Titan it was theorized in peer-reviewed research that if life existed on Titan, it would most likely consume ethane and acetylene as fuel, burn it with hydrogen instead of oxygen, and produce methane instead of CO2. Subsequent measurements revealed that Titan's surface is unexpectedly ethane-poor, highly acetlyene poor versus how much is being produced in the atmosphere, and one tenative study reveals that hydrogen is disappearing at the surface too.
* A recent study shows that if it reached sufficient concentration, any acrylonitrile dissolved in Titan's hydrocarbon lakes would naturally form membranes with properties almost identical to the properties of phospholipid membranes on Earth. It just so happens that we've already detected acrylonitrile in Titan's atmosphere.
And on and on. Does any of this mean that there "is" life on Titan? No, not at all. But it's orders of magnitude more evidence than we have for life being at any of the other "popular" places like Mars with its peroxide-rich regolith that destroys organics on contact or Europa's undersea ocean that we know virtually zilch about. And there's an awful lot of mysteries about Titan that warrant solving, life or not. For example, even if there was some non-organic catalyst on Titan breaking down acetylene on the surface, it'd sure be amazing and potentially quite useful to know what sort of natural inorganic catalyst could do that at 100K. And even if Titan turns out to be the worst case - a "frozen early Earth" - well, geez, the knowledge we'd gain toward understanding where we came from in studying the organic chemistry there would be amazing.
The 'needing humans for digging and cracking rocks' remark is particularly stupid in light of the fact that the current probes already dig and crack rocks to some extent, and NASA's about to launch a probe that takes digging and rock cracking to a whole new level (although for a different purpose). The concept that humans are some sort of ideal digging, rock cracking system is crazy.
The ability to conduct science using human physical and sensory capabilities is highly limited. Science is conducted using scientific equipment. Humans operate it either way, the only major difference between a robot and a physical presence is higher latency for robots, and orders of magnitude greater cost for humans. Given the length of time between missions anyway due to budget constraints, the latency issue is borderline irrelevant.
Of course, objects that are visible in the visible spectrum can be translucent or transparent at other frequencies. That said, translucency (and reflection for that matter) are confusing for LIDAR. But there's potential there for some day in the (non-immediate) future.
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You're mistaken. The main reason desal plants consume so much energy in pumping is not due to sea level changes, it's to provide sufficient osmotic pressure for the membranes. Freshwater is in a higher energy state than saltwater, and that energy must be provided in some way or another. In the brine desalination system, it's provided by the sun evaporating seawater to brine. In a conventional osmotic system it's electricity running pumps.
Sunlight is free**. Electricity is one of the most expensive forms of energy commonly used by humans.
** - Apart from your capturing system. But the beauty part here is how incredibly cheap the capture system is vs. how much solar energy it captures.
On the decision of whether to sacrifice an industry to provide the substance that people need to live, then YES.
And that's folks is why being an arse when you disagree with someone is usually mutually exclusive with being able to write proper English.
The flames in a house fire can of course be "over a thousand degrees F". Most air in a burning house is below the boiling point of water. But hey, let's just assume that your bucket is sitting right on top of the ignition source of your house and somehow remains directly in flames underneath it for half an hour. Gee, what sort of analogy could we have for a large metal pot-like thing sitting on some gas stove-like flames... oh yeah, how about a pot sitting on a gas stove (whose flames can also be "over a thousand degrees F")? Because anyone who's ever put a large pot full of water on the stove (for example for canning) can tell you that it will NOT boil off in half an hour.
And seriously, a steel bucket will be "gone"? Methinks you need to look up the melting point of steel.
Or for something cheaper, M-Disc in a bucket of water. Water shouldn't get significantly over boiling in a fire (as it loses its heat by boiling off), and M-Disc is rated to withstand boiling water and not degrade from long-term water immersion (they're burned not by modifying a photosensitive dye like in normal discs, but by literally etching a hard, inorganic layer)
All thermal power plants (which make up the vast majority of power plants) can do that, so that buys you nothing in favor of nuclear in particular.
*I'm* saying that when people and businesses are struggling to get water, and there's *one* industry out there that's only a tiny portion of the economy that's making everyone else suffer, then it's a situation that ought to be remedied.
Nuclear power is expensive. Desalination water is expensive because of the electricity cost. Are you proposing to raise the cost even further?
Let's just take this at face value, and let's falsely pretend that the water shortages aren't also causing cutbacks by residential consumers. Then that's 40% of the state's water to provide a fraction of 2% of the GDP, in drought conditions.
Even in your scenario, do you think this is appropriate?
I wonder if they could help increase the economic picture via value-added product recovery from the discharge brine. The oceans have an interesting mix of dissolved minerals and there's already interest in recovery of a number of them; perhaps the concentration of the discharge brine could help improve their economics a bit.
(of course, what I find a more interesting possibility for recovery is mining the pacific garbage patch for minerals that have over the course of years soaked up into the plastic from the seawater)
Agriculture is the big culprit, taking 80% of the state's water (and in return ag and mining together only make up 2% of the economy). Its a totally unsustainable situation that has to be remedied sooner or later.
That said, I do have hope for the future of desalination. Not with current techs (as with the one in the article, they're energy hungry and expensive), but potentially with new techs that don't rely on electricity as their power source. One I find interesting is this one. Basically, it relies on evaporation, which isn't unique... but *not* by capturing the evaporated water. It's just concentrated salt solution that's desired, which means that you don't need some sort of elaborate vapor capture system and sealed tanks, just simply any sort of open area that can hold water - even an endoherric basin or jettied-off chunk of ocean. Far, far cheaper.
Concentrated brine is turned into freshwater via ion bridges: it's connected to two tanks of normal seawater, one by a positive ion bridge and the other by a negative ion bridge. The brine greatly wants to dilute into the normal seawater, but it can't because the ions would be imbalanced in the two side tanks. So these two side tanks are connected to a third tank of seawater with the opposite ion bridges, so that salt can dilute from the brine into the two seawater tanks, but only if they also "suck" the opposite ion out of the final seawater tank. Since the brine concentrated brine wants to dilute so much, the action is energetically favorable and continues until there's no salt left in the third tank - aka, it's freshwater. (An actual implementation would be a continuous process, not fixed tanks, of course)
Apart from basic pumping needs, there's no electricity needed. The energy source is just "sun falling on any water chunk of seawater that's not free to circulate with the open ocean". You might even be able to have it filled automatically in some places via the tides or waves breaking over a jetty without having to pump new seawater in, leaving the only pumping needs for distribution.
Of course, the main tech limitation right now is making the salt bridges have high enough throughput and reliability to justify the capital costs.
Your first example sounds weird, and the second is unambiguously not valid English. Neither express exactly the same sense of action as the example. And the sentence I gave was just one example out of countless. Word genders are just word groupings which help reduce sentence ambiguity. You can detach them from the concept of a human gender; you could call them wizzlewozzles, it makes no difference. They just reuse the pronouns from actual gendered beings, which saves some linguistic space.
Also, the concept that one has to learn a gender for each word... first off, in most languages with genders, there's patterns for recognizing what words are what gender. They're not always universal, of course (in an ideal language they would be simple and universal), but they're important. Secondly, there's all sorts of data a person has to learn about each word to be able to speak properly as it is. Even if you have to learn a gender for each word, patterns aside, it's just a tiny piece in a much larger puzzle - that puzzle being reliably and concisely transmitting information across a noisy connection.
With three genders in Icelandic, the odds of a collision between an arbitrary two is only one in three. As you might say, "good enough for government work". Languages are never, and can never be "perfect", there's always tradeoffs on how you allocate space. But I have to say, your example of how to do it in English was a pretty bad tradeoff (having to repeat "the backhoe")
Corr: stirling, not sterling ;)
The whole point of "from the air" is that you can land. And take off and land and take off again and again. It's not exactly tricky to raise or lower altitude. ;) And on Titan, low gravity plus a dense atmosphere yields very low terminal velocities, i.e. cushy landings without much effort. But even if you're not talking about landing, you absolutely can do a lot more by virtue of being able to get so much closer to the surface. Much of science is about resolution.
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The issue isn't average temperatures. The issue is temperature ranges. Having to tolerate a single very cold temperature is far easier then having to tolerate temperatures that range from very cold to very hot. The biggest challenge for Huygens wasn't tolerating the cold of Titan, it was tolerating the cold of Titan *and* the solar heat from flying near Venus.
The average day-night temperature on Mars is a 100K difference. Seasons add another 45 on top of that. This repeated thermal cycling incredibly stressful on all of a rover's systems. It also mandates a much more complex thermal management system. For example, Curiosity uses a system of computer controlled pumps to pump a cooling fluid from its RTG either to the probe internals or to the radiators based on the ambient temperature. If it wasn't an actively managed heat flow it could overheat the probe in the summer or freeze the probe in the winter.
Remember, it was ultimately winter that killed Spirit. Had the temperature been steady, and Spirit been designed to handle that steady temperature, this would not have happened. When you have a very specific temperature envelope, it's just a situation of "insulate and add radiothermal heaters or heat output from the RTG wherever needed". It's a lot more complicated when it fluctuates.
And contrary to popular belief, it doesn't get harder to heat as the temperature gets colder, it actually gets easier - that is to say, the amount of energy needed to heat a craft to 300K in a 100K environment isn't dramatically higher than the amount of energy needed to heat it to 300K in a 200K environment, far less than double (the exact details depend on the situation). Radiative heat loss is proportional to the temperature to the fourth power, so it drops off to nearly nothing at low temperatures (we'll just ignore for now that on Titan you're also not exchanging heat with the vacuum of space, rather the upper atmosphere). Convection on Titan is also greatly slowed. That's why the calculations show that you can heat a whole sizeable hot "air" blimp on Titan with just an RTG (that, and how much lift you get for how little effort!).
Yet people use RTGs aplenty - even on Mars where it's possible to use solar. Almost half of successful actively-powered Mars surface probes have been RTG powered - the two Viking landers and Curiosity vs. Pathfinder, Spirit, Opportunity, and Phoenix. RTGs are more reliable, simpler, and provide useful heat. But they're also expensive, which is the main reason for the inner / outer solar system solar / RTG dichotomy that Mars straddles. A typical high power RTG may cost on the order of $100M. Not a big deal if it's a Flagship mission, maybe a big deal if it's a New Frontiers mission, and definitely a big deal if it's a Discovery mission. It'd be nice if a Sterling version could be finally developed, that'd be another big facilitator for outer planet missions by bringin
For fun. Why not humor the submitter?
To the submitter: Okay, I'd start with saying, "don't reinvent the wheel more than necessary". So for example, consider IPA as the writing system. Or if you want to invent a writing system to be optimized by a given set of rules, at least consider using the IPA forms as your basis.
Consider who your target learners are. Is it the whole world? Any particular weighting that you want to apply with certain native tongues? Check and see what phonemes and linguistic rules are common in the languages by whatever weighting you want to apply.
When doing your weighting to decide what phonemes to use, don't only consider "whether the language has it", but also "how easy is ot for people to learn who don't know how to do it. For example, among the sounds in Icelandic that aren't in English there's the "ll" lateral plosive and the alveolar trill "r". The "ll" is nothing like anything found in English, yet given a simple description most English speakers can pronounce it perfectly. On the other hand, some people struggle for years and never manage to learn a trilled "r".
That is, all to say, an ideal language takes research not just on what phonemes people use, but what phonemes are easy to learn.
Then there's one of the biggest issues, which is intelligibility. You want the most diverse array of phonemes possible without being likely for the listener to confuse two similar ones together. Again, research would pay off big here.
The exact same rule applies to vocabulary / grammar, and this is unfortunately one thing that constructed languages usually suffer from relative to evolved ones. If English had the word "dog" like it is now, but the word for cat was "dawg" with only a slightly different pronunciation, these two common everyday words would lead to a lot of confusion. This normally gets steadily selected out either with pronunciation shifts or the adoption of alternative words.
If you really want to get into it, you could write an evolutionary algorithm to optimize your vocabulary and/or grammar to maximize the auditory difference between different common words and word phrases. The goal is to keep that signal to noise ratio up to maximize understandability. :)
One I'd recommend is something that Icelandic does: having a simple, universal stress rule. That is, the first syllable of every word, and the first part of every compound with at least one syllable between them, is stressed. And when I say stressed I mean literally double the length of the others. What this does is make it so that even a beginner can tell exactly where one word or part of word ends and the next begins.
A couple things that English speakers often attack about other languages you should think about instead of just readily dismissing them:
1. Genders. It seems archaic, right? But there are practical reasons. For example, consider the sentence:
"I used a backhoe to drag a box but it was ruined in the process"
Which is ruined, the backhoe or the box? In Icelandic it's obvious because a backhoe is feminine but a box is masculine. Sorting words into differing groups adds some clarity to sentences. It comes at the cost of increasing the amount of knowledge needed for each word (this is usually done by breaking words into patterns, such as "if it ends with these letters, it's in this group"). You could, for example, have such a grouping (calling it something other than gender), but have the rules for determining whether a thing is in a particular group be really obvious. Taking a direct from English example, if we wanted many groups, one for each last phoneme in the word, the above could become:
"I used a backhoe to drag a box but itoe was ruined in the process."
Now it's obvious to a "native" speaker of our constructed language that the particular word for "it" refers to the backhoe.
The other thing English speakers often complain about is declensions. But once again, they're another example of giving additional info
Again, Captain Strawman strikes. I am mortally wounded!
Thank you for your input, Captain Strawman.
Yes, everybody on the planet does. Online 3d print services are everywhere nowadays.
I didn't say "cracked into a million pieces"; it simply no longer had the structural integrity to stay in its slot in the door and my attempts to glue together in a manner that would restore its structural integrity without having it ending up looking hideous failed in both respects. It was still one piece though.
Even if a scanner could detect the cracks, it's not hard to picture the interface having a trivial "crack repair" filter. I'd expect it to be part of any basic package along with rust removal, scratch removal, corner wear repair, etc; it's not algorithmically complex by any means; the first is just vertex merging within a given radius, the second could take several forms, the third is a selective gaussian blur filter, the fourth is a selective sharpening filter, etc. Popular 3d editors like Blender already have functions that can do all of these sorts of stuff and more.
In many ways, Titan is an easier world than Mars (no question that Europa is the odd one out, we're nowhere close to being able to get a probe to explore its oceans). If it wasn't for the distance, it'd be far easier and safer. Lower gravity plus a nice thick atmosphere makes it so easy to aerobrake and gives you tons of great ways to get around (balloons, blimps, helicopters, fixed-wing aircraft, tilt-rotor craft, etc). Moving by air is not only orders of magnitude faster, but - so long as the air is stable, which it appears to be on Titan - safer, too. Surface rovers can and regularly do get stuck, and sometimes it's fatal. The low gravity and dense atmosphere helps with lots of other stuff too - for example, huygens was able to touch down just with a simple parachute, no retrorockets needed (touchdown is always a very nail-biting step in any Mars mission, there's so much that can go wrong with whichever approach you use, even with all of our experience). Plus on Titan there's little electrostatic blowing dust, your radiation levels are lower, your temperatures are more stable, etc
The distance of course is the one big pain with Titan, and it majorly affects a number of things - your delta-V reqs, your transit times, your communication bandwidth / power / weight tradeoffs, your launch windows, etc, and also mandates the use of nuclear power, where on Mars it's only one of two options. Ion engines are thankfully helping to "shrink" our solar system, but no question, the distance is a real big disadvantage for Titan vs. Mars.
But it's really the only major disadvantage. It's so easy to land and get around once you're there.
Okay, you're on Mars. You discover that there's a neat rock that the instruments you were sent with aren't good enough to completely. You could use some more data. Perhaps thermal conductivity? Okay, go ahead and make a thermal conductivity probe on Mars with enough accuracy to be useful. Maybe one possibility is sensitive to, say, hydrofluoric acid? Go ahead, make some hydrofluoric on Mars. Well, what about a streak or hardness test? Aha, a human could come up with a way to do that by using some other tools or other objects for purposes they weren't designed for! But you know what? So could a robot.
You might be able to come up with some edge case that a human could do that a robot couldn't. But "edge cases" don't pay for increasing the budget by orders of magnitude.
Unless you're talking about "gee whiz" factors, no. A proper payload can replicate your senses in far more accuracy in far less mass. Your eyes are cool and all, but their eyes can zoom, record readings at each spectral frequency, see IR and UV, see polarization, etc. Your sense of touch is cool and all, but theirs can get precise measurements of thermal conductivity, electrical conductivity, etc. Your sense of smell is neat and all, but versus a mass spectrometer? Just no. And on and on. You are not a scientific instrument. The only thing you really have going for you is your brain. And you know what? That works just fine here on Earth, regardless of how it gets its data.
The economic knock-on effects of building a bigger rocket to carry people, tons of supplies, radiation shielding, etc, versus instead using the same money to build dozens of diverse robots with all kinds of diverse scientific equipment? Absolutely no contest there that the latter will pay off better.
Like, "Wow, that sure cost a DAMNED lot of money!"
What I really want to see is a single ambitious Titan mission that could answer nearly all of the questions we have today (while undoubtedly making tons of new ones... ah, the beauty of science ;) ):
* The craft would consist of (beyond its initial boost) a propulsion/communication module, an exploration module, and an ascent module.
* The propulsion module would use its RTG power, plus the power from the RTG of the attached exploration module, to run the ion engine, draining its tank to near empty to get into a low Titan orbit through the ionosphere.
* The explorer and attached ascent module would be released, to slowly have their orbits decay to capture, while the propulsion module would remain in low orbit acting as a communications relay (thus keeping down the weight and power requirements for the explorer).
* During its time in orbit, the propulsion module would be acting as an electrostatic "scoop" through Titan's ionosphere. Its orbit being about 1500m/s but its exhaust velocity being tens to hundreds of thousands of meters per second, it should be able to scoop up gas to use as propellant without being overcome by drag (most ion engines are propellant flexible). Over the course of a year or so it should be able to fill up its tank.
* Apart from this feature, the propulsion stage (now an orbiter) is kept simple - for example, no radar or other power hungry, heavy scientific equipment.
* After a couple weeks of losing velocity and altitude, the explorer and ascent stage's orbit will fully decay. The explorer would be a tilt-rotor aircraft with pontoons. Autorotation of the props would slow down the stage during descent, and then active powered thrust at high throttle would reduce the landing velocity.
* The ascent stage, a couple hundred kilograms, would significantly outweigh the explorer, at a several dozen kilograms. The explorer would disconnect from it before roaming the planet, an activity which would be done as a series of daily hops: 1) The craft climbs straight up like a helicopter, then 2) tilts its wings forward to fly as an airplane, in order to get maximum range out of minimum power - a few hundred kilometers per flight. 3) It flies to the location decided the day before while collecting aerial imagery, then 4) does a vertical descent. 5) On the surface it rests for about a day while it does surface science, transmits data, and waits for the next day's instructions while its RTG recharges its flight batteries.
* Small samples (a few grams each) are collected from each location, whether solid or liquid, and individually chambered in a honeycomb-like storage bay.
* With that sort of range capability and about a year of exploration time, the probe could probably explore pretty much every major interesting feature on the planet (while identifying no shortage of future targets, no doubt).
* At the end of its mission it returns to the ascent stage and docks with it. If the probe is capable of lifting the ascent stage (most likely the best option), it achieves the maximum altitude and delta-V it is capable of with its flight batteries before firing the stage; the stage would thus require somewhere around 1,7k m/s delta-V. If the ascent stage has to be launched from the surface, then it needs an additional 0,5-1k.
* In orbit it moves to an intercept orbit with the now-full propulsion stage and ejects the ascent stage. The propulsion stage docks with it and begins spiraling away from Titan to an Earth-return trajectory using the combined power of the two RTGs.
* Any of several possible recovery methods are used at Earth to recover not just the sample pack from the explorer, but any residual propellant (aka, Titan's atmosphere) from the propulsion stage tanks. If the propulsion stage uses multiple tanks then different tanks could be filled from different areas of Titan's outer atmosphere.
Sample return and detailed imagery from every interesting portio
Good question. NASA seems to be on a search obsessively focused on the concept "liquid water touching bedrock equals life, anywhere without liquid water touching bedrock equals no life". There's so many things wrong with this concept I don't even know where to start. We don't even know if the first forms of life on our own planet developed that way, let alone whether it's common or rare and whether other possibilities are common or rare.
It bothers me because it causes them to obsess over certain bodies (Mars, Europa) while ignoring others. Personally, if I was hunting for life, of all the places in the solar system outside of Earth, I'd pick Titan (which usually gets ignored because it's so cold).
* It's bigger (although not heavier) than Mercury, and has a predominantly nitrogen atmosphere denser than Earth, with a full meteorological cycle.
* We know that there's complex organic chemistry going on en masse there. Today.
* We've detected dozens of types of complex organic chemicals already even with our limited study and we know we're only scratching the surface. Unidentified chemicals around 10000 daltons have been detected in the atmosphere. There's probably even more complex chemicals on the surface. There's so much complex organics there that it blankets the surface in places.
* There's not one type of liquid on Titan but multiple - an underground sea (which reaches the surface through cryovolcanoes, we're pretty certain) and surface seas of hydrocarbons of what appear to be significantly varying compositions.
* Titan's methane is regenerating itself. We don't know why. On Mars they treat the presence of unexpected methane as an incredible sign of possible life, on Titan it's treated just as a "Huh, weird" thing
* Before the details of what was going on on Titan it was theorized in peer-reviewed research that if life existed on Titan, it would most likely consume ethane and acetylene as fuel, burn it with hydrogen instead of oxygen, and produce methane instead of CO2. Subsequent measurements revealed that Titan's surface is unexpectedly ethane-poor, highly acetlyene poor versus how much is being produced in the atmosphere, and one tenative study reveals that hydrogen is disappearing at the surface too.
* A recent study shows that if it reached sufficient concentration, any acrylonitrile dissolved in Titan's hydrocarbon lakes would naturally form membranes with properties almost identical to the properties of phospholipid membranes on Earth. It just so happens that we've already detected acrylonitrile in Titan's atmosphere.
And on and on. Does any of this mean that there "is" life on Titan? No, not at all. But it's orders of magnitude more evidence than we have for life being at any of the other "popular" places like Mars with its peroxide-rich regolith that destroys organics on contact or Europa's undersea ocean that we know virtually zilch about. And there's an awful lot of mysteries about Titan that warrant solving, life or not. For example, even if there was some non-organic catalyst on Titan breaking down acetylene on the surface, it'd sure be amazing and potentially quite useful to know what sort of natural inorganic catalyst could do that at 100K. And even if Titan turns out to be the worst case - a "frozen early Earth" - well, geez, the knowledge we'd gain toward understanding where we came from in studying the organic chemistry there would be amazing.
The 'needing humans for digging and cracking rocks' remark is particularly stupid in light of the fact that the current probes already dig and crack rocks to some extent, and NASA's about to launch a probe that takes digging and rock cracking to a whole new level (although for a different purpose). The concept that humans are some sort of ideal digging, rock cracking system is crazy.
The ability to conduct science using human physical and sensory capabilities is highly limited. Science is conducted using scientific equipment. Humans operate it either way, the only major difference between a robot and a physical presence is higher latency for robots, and orders of magnitude greater cost for humans. Given the length of time between missions anyway due to budget constraints, the latency issue is borderline irrelevant.
Of course, objects that are visible in the visible spectrum can be translucent or transparent at other frequencies. That said, translucency (and reflection for that matter) are confusing for LIDAR. But there's potential there for some day in the (non-immediate) future.