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posted by janrinok on Thursday September 29 2016, @07:35PM   Printer-friendly
from the worth-a-try dept.

Submitted via IRC for Bytram

Researchers led by NASA's former chief technologist are hoping to launch a satellite carrying water as the source of its fuel. The team from Cornell University, guided by Mason Peck, want their device to become the first shoebox-sized "CubeSat" to orbit the moon, while demonstrating the potential of water as a source of spacecraft fuel. It's a safe, stable substance that's relatively common even in space, but could also find greater use here on Earth as we search for alternatives to fossil fuels.

Water is a way around this issue because it is essentially an energy carrier rather than a fuel. The Cornell team isn't planning to use water itself as a propellant but to rather use electricity from solar panels to split the water into hydrogen and oxygen and use them as the fuel. The two gasses, when recombined and ignited will burn or explode, giving out the energy that they took in during the splitting process. This combustion of gasses can be used to drive the satellite forward, gaining speed or altering its position in orbit of whichever desired planet or moon is the target.

Solar panels, with high reliability and no moving parts, are ideally suited to operate in zero gravity and in the extreme environments of space, producing current from sunlight and allowing the satellite to actively engage on its mission. Traditionally this energy is stored in batteries. But the Cornell scientists want to use it to create their fuel source by splitting the on-board water.

Source: http://phys.org/news/2016-09-space-rocket-fuel-power-revolution.html


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  • (Score: 4, Insightful) by Immerman on Thursday September 29 2016, @07:54PM

    by Immerman (3985) on Thursday September 29 2016, @07:54PM (#408093)

    Okay, cool tech, and I could see it being useful in space as a stable, dense storage form for reaction mass for maneuvering jets and other highly intermittent uses.

    But on Earth? In what way is this an alternative to fossil fuels? It's no alternative at all as an energy *source*, and hydrogen has long ben under consideration as a form of energy *storage*, but presents some major challenges that, last I heard, are as yet unsolved. Moreover, until solar power generation exceeds consumption, electrolysis is a wasteful use of that electricity.

    I also seem to recall that there are numerous groups pursuing methods of water splitting, several using solar power, that exceed the production efficiency of photovoltaics+electrolysis, but are still not cost-competitive with fossil fuels.

    Sounds more like someone is just trying to put some "Earth use" spin on something that's not really relevant.

    • (Score: 2) by takyon on Thursday September 29 2016, @08:30PM

      by takyon (881) <reversethis-{gro ... s} {ta} {noykat}> on Thursday September 29 2016, @08:30PM (#408107) Journal

      I'd mod you up but I blew my mod wad.

      Solar and Fusion Could Drive a Power Revolution on Earth. If one of the several new nuclear fusion startups succeeds, we could have 0.1 to 1.0 cents per kilowatt-hour electricity.

      --
      [SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
    • (Score: 3, Interesting) by edIII on Thursday September 29 2016, @08:32PM

      by edIII (791) on Thursday September 29 2016, @08:32PM (#408108)

      I remember that there is an aluminum/gallium process for hydrogen production from water that allows you store the hydrogen safely. No metal hydrides or anything else is required for storing hydrogen. The hydrogen is produced on demand by introducing water into the Al/Ga chamber which results in oxygen forming an oxide with aluminum, and the hydrogen being released. The gallium acts as a "catalyst" (iirc) that prevents the reaction from stopping and allows it to continue until either the aluminum or water is exhausted.

      The only caveat about the process is that you require considerable amounts of energy to reclaim the Al/Ga through standard processing that removes the oxygen. If we improve the reclamation process, we have a method of both transporting water for energy storage, and extracting out hydrogen as needed. Safely.

      --
      Technically, lunchtime is at any moment. It's just a wave function.
      • (Score: 3, Interesting) by aristarchus on Thursday September 29 2016, @08:41PM

        by aristarchus (2645) on Thursday September 29 2016, @08:41PM (#408112) Journal

        But if the oxygen is bonded to the Al, what are you going to use to combust the hydrogen? Are you thinking terrestially, where you have access to things like an atmosphere? What is so difficult about solar electrolysis?

        • (Score: 2) by requerdanos on Thursday September 29 2016, @09:08PM

          by requerdanos (5997) Subscriber Badge on Thursday September 29 2016, @09:08PM (#408119) Journal

          What is so difficult about solar electrolysis?

          Well, I think the problem with it is that is not all that difficult, but the energy you get from it is proportional to the effort put in.

          Consider the following:

          Energy "a" released from the Sun on a small area -> photocell with significant ineffeciency -> electrolyzer that frees up hydrogen -> hydrogen with stored energy "b"

          The problems with this stem from the facts that (1) "b" is much, much smaller than "a", and (2) "a" was not all that big to begin with.

          It's like having almost nothing, and turning it into the limit of nothing as it approaches zero, but in a conveniently portable form.

        • (Score: 2) by edIII on Thursday September 29 2016, @09:35PM

          by edIII (791) on Thursday September 29 2016, @09:35PM (#408127)

          I hadn't thought beyond the production of hydrogen to be honest, and yes terrestrially. Thanks for pointing that out.

          --
          Technically, lunchtime is at any moment. It's just a wave function.
        • (Score: 1) by nitehawk214 on Friday September 30 2016, @05:07AM

          by nitehawk214 (1304) on Friday September 30 2016, @05:07AM (#408253)

          Hell with electrolysis. Thermally split water:

          https://en.wikipedia.org/wiki/Water_splitting#Solar-thermal [wikipedia.org]

          --
          "Don't you ever miss the days when you used to be nostalgic?" -Loiosh
          • (Score: 3, Funny) by aristarchus on Friday September 30 2016, @06:27AM

            by aristarchus (2645) on Friday September 30 2016, @06:27AM (#408266) Journal

            Wow! Who knew there were so many ways to split water? I am partial, however, to "Water splitting by Iridium complexes", because Iridium, as we all know, is the primary material used to tip the nibs of fountain pens. And the inks used by fountain pens are almost entirely water. So do we have an energy source, and an output of good literature?

    • (Score: 1) by RS3 on Thursday September 29 2016, @11:05PM

      by RS3 (6367) on Thursday September 29 2016, @11:05PM (#408153)

      But on Earth? In what way is this an alternative to fossil fuels? It's no alternative at all as an energy *source*, and hydrogen has long ben under consideration as a form of energy *storage*, but presents some major challenges that, last I heard, are as yet unsolved. Moreover, until solar power generation exceeds consumption, electrolysis is a wasteful use of that electricity.

      It's a bit difficult- lossy and expensive- to "ship" electricity from sunny desert areas to populated cities. I've long envisioned large solar-powered generating systems out in desert areas, or floating on the ocean, producing hydrogen and oxygen from water. You can pipe the H and O with far less loss than conduct electricity over long distances. True it would need to be built really well and well protected, safety shutdowns, etc. You could then run the H and O into fuel cells for electricity or use it for vehicles, etc...

      • (Score: 2) by Immerman on Thursday September 29 2016, @11:13PM

        by Immerman (3985) on Thursday September 29 2016, @11:13PM (#408161)

        Have we worked out any way to pipe H2 long distances without massive losses though? Even at atmospheric pressure, you're still dealing with roughly zero partial pressure on the outside of the pipe wall, so you need a wall that H2 can't flow through.

        • (Score: 1) by RS3 on Friday September 30 2016, @12:39AM

          by RS3 (6367) on Friday September 30 2016, @12:39AM (#408184)

          I don't know about these things of which you speak. You're saying H2 can leech through things? Such that over long distances, the huge surface area of the pipe would be a sieve? Could we coat it with PTFE or something similar? How about a small gauge rail system with canisters?

          • (Score: 0) by Anonymous Coward on Friday September 30 2016, @01:33AM

            by Anonymous Coward on Friday September 30 2016, @01:33AM (#408196)

            Send the hydrogen-filled canisters through the Hyperloop.

          • (Score: 2) by Immerman on Friday September 30 2016, @05:37PM

            by Immerman (3985) on Friday September 30 2016, @05:37PM (#408455)

            In case that wasn't humor...

            Yes H2 is pretty much the smallest stable particle in the universe - a tiny "barbell" about as long as a Helium atom is wide, and considerably narrower, capable of slipping right through most molecular lattices. One of the major obstacles to hydrogen usage is that H2 will rapidly leak right through the walls of pretty much any container you put it in. I looked for info suggesting that PTFE could be used for containment, but from what I found it sounds like it's only good by the generally low standards of polymers. And strings of canisters only make it worse by increasing the surface area for a given volume of hydrogen.

            That's not to say that it couldn't be done, but it's worth asking whether it would actually be significantly more efficient than standard power lines, especially after the higher construction and maintenance costs are factored in (in energy as well as money).

            And of course there's also another alternative for transporting electricity long distances - superconducting power lines. As I recall there's long been a project in the works to build such a line between Europe and the vast solar potential of the Sahara, stalled in large part due to the political instability in Africa rather than any technical or economic objections.

      • (Score: 2) by WalksOnDirt on Thursday September 29 2016, @11:29PM

        by WalksOnDirt (5854) on Thursday September 29 2016, @11:29PM (#408164) Journal

        The losses of energy of gasses flowing through a pipe depends on the speed. If you are willing to wait forever then it's free. If you want if faster it gets expensive.

        • (Score: 1) by RS3 on Friday September 30 2016, @12:42AM

          by RS3 (6367) on Friday September 30 2016, @12:42AM (#408187)

          Would larger ID pipe cause less loss?

        • (Score: 2) by Immerman on Friday September 30 2016, @05:41PM

          by Immerman (3985) on Friday September 30 2016, @05:41PM (#408461)

          I hadn't even considered those losses, and they're definitely worth factoring in.

          Hydrogen specifically though offers some unique challenges, because it can leak right through seamless steel, and pretty much anything else. An H2 molecule is the smallest stable particle in the universe, and can fit through all but the tiniest intermolecular gaps.

      • (Score: 2) by stormwyrm on Friday September 30 2016, @12:31AM

        by stormwyrm (717) on Friday September 30 2016, @12:31AM (#408180) Journal

        If you had an easy way to make hydrogen, why not turn that hydrogen into methane? Last I checked, storing methane safely for extended periods is comparatively easy: in my own kitchen, I have some stored methane in a gas cylinder. Transporting methane long distances is also a lot easier: it's something the petroleum industry has long done. Just about any ordinary motorcar can very easily be modified to use methane as fuel instead of petrol. The analogous problems for plain hydrogen don't yet seem to have practical solutions. There seems to be something called the Sabatier reaction [wikipedia.org] which can convert H and CO2 into methane and oxygen with a nickel catalyst. Methane produced this way would be carbon-neutral, provided that the hydrogen it was made from were also carbon-neutral.

        --
        Numquam ponenda est pluralitas sine necessitate.
        • (Score: 0) by Anonymous Coward on Friday September 30 2016, @04:56PM

          by Anonymous Coward on Friday September 30 2016, @04:56PM (#408439)
          How much more expensive and difficult would it be to go all the way to hexane or similar? Storing and transporting liquid hydrocarbons should be even easier than for methane.
          • (Score: 0) by Anonymous Coward on Saturday October 01 2016, @12:37AM

            by Anonymous Coward on Saturday October 01 2016, @12:37AM (#408600)

            That's what the Fischer-Tropsch process [wikipedia.org] is for. It's already being used by petroleum refineries on large scales today.

        • (Score: 2) by Immerman on Friday September 30 2016, @05:45PM

          by Immerman (3985) on Friday September 30 2016, @05:45PM (#408465)

          An interesting idea. I would wonder though how losses to inefficiencies in the process, and the energy required to collect and concentrate CO2 to feed it, would compare to those of electrical transmission lines.

  • (Score: 0) by Anonymous Coward on Thursday September 29 2016, @10:12PM

    by Anonymous Coward on Thursday September 29 2016, @10:12PM (#408134)

    IGNITION!
    An Informal History of Liquid Rocket Propellants

    https://library.sciencemadness.org/library/books/ignition.pdf [sciencemadness.org]

    I came across this book a few days ago and almost was going to submit it as a journal/slow news day/book review. The book seems worth reading, so you should give it a quick skim and see if it catches your interest.

  • (Score: 2, Interesting) by butthurt on Thursday September 29 2016, @11:07PM

    by butthurt (6141) on Thursday September 29 2016, @11:07PM (#408154) Journal

    Thank you, space people, but we already use this technology.

    The oxy-hydrogen blowpipe was developed by English mineralogist Edward Daniel Clarke and American chemist Robert Hare in the early nineteenth century. It produced a flame hot enough to melt such refractory materials as platinum, porcelain, fire brick, and corundum, and was a valuable tool in several fields of science.

    -- https://en.wikipedia.org/wiki/Oxyhydrogen [wikipedia.org]

    DR. CLARKE'S EXPERIMENTS WITH THE OXY-HYDROGEN BLOWPIPE.

    781. The series of experiments made by Dr Clarke with the gas blowpipe, was the most important which has ever been made on mineral bodies exposed to so high a temperature. In a work like the present it is, therefore, but right to bestow a considerable degree of attention upon these experiments. We have consequently drawn up a short description of the most remarkable phenomena attending the fusion of various bodies which were tried, and of the results which that fusion produced. The length of this account, much as we have studied brevity in its composition, incroaches considerably on the limits of our little volume; yet we consider it of too important a nature to be farther shortened or omitted.—The student will acquire a fund of useful information by the comparison of these experiments with those described in the preceding pages as made with the mouth blowpipe; the results in the two cases, when a mineral is assayed with the gas and with the common blowpipe, being sometimes exceedingly curious. If he possesses a gas blowpipe, this account will serve as a manual whereby he may direct his operations; and should he be desirous of acquiring more extensive information on the subject, he has only to consult "The Gas Blowpipe, or the Art of Fusion by Burning the Gaseous constituents of Water," published by Dr Clarke about eight years ago.

    -- https://books.google.com/books?id=YbsQAAAAIAAJ&pg=PA270&output=text#PA270 [google.com]

  • (Score: 2) by jmorris on Friday September 30 2016, @12:33AM

    by jmorris (4844) on Friday September 30 2016, @12:33AM (#408182)

    If they are just testing the tech, ok. If you can find a source of water up there to use as the input this makes some sense, otherwise it is pointless.

    Do the math peeps. Option 1, carry hydrogen and oxygen precracked in tanks and light it up. Option 2, carry the same mass as water plus solar collectors and the equipment to crack it and then light it up.

    Better still would be to use electricity to fire random mass out at super energy levels greater than just lighting it up if we can't get the crazy microwave drive working.

    • (Score: 2) by butthurt on Friday September 30 2016, @01:49AM

      by butthurt (6141) on Friday September 30 2016, @01:49AM (#408199) Journal

      In 1807, the first wheeled vehicle with an internal combustion engine ran on hydrogen. There have been other attempts since.

      https://web.archive.org/web/20080119155832/http://www.hydrogencarsnow.com/hydrogencars1807-1986.htm [archive.org]

    • (Score: 2) by butthurt on Friday September 30 2016, @02:05AM

      by butthurt (6141) on Friday September 30 2016, @02:05AM (#408203) Journal

      It's more equipment than I expected: the article says that a centrifuge separates the gasses from the water.

      > Better still would be to use electricity to fire random mass out at super energy levels greater than just lighting it up [...]

      Yes, ion drives are a thing.

      • (Score: 2) by jmorris on Friday September 30 2016, @02:28AM

        by jmorris (4844) on Friday September 30 2016, @02:28AM (#408210)

        Yup. Current ones use Xenon, but while a noble gas might simplify some of the design there should not be any unsolvable obstacle to firing any old mass you happen to have out the rear at very speed.

        • (Score: 1) by Tara Li on Friday September 30 2016, @02:51PM

          by Tara Li (6248) on Friday September 30 2016, @02:51PM (#408396)

          Indeed. The Dawn Probe lifted off with about 425 kg of Xenon for its mission. It made two asteroid rendezvous and one orbit escape on it, plus a Mars gravity slingshot, plus other assorted orbital adjustments and maneuvering.

          I'm thinking ... Musk's Interplanetary Transporter, attached to a station that makes figure-8s between Earth & Mars, using ion thrusters to build the carrier ship up to a damned good pace. Momentum bank tether stations... Seriously.

          And that monster big ship Musk is talking about sending 100 people & 100 tons of cargo to Mars with? How would it do for a Lunar mission? Big, big ship - but for a 3 day trip instead of a three month one? MMmmmmm..... After the first is built, how much to build the second, or third?

    • (Score: 1) by khallow on Friday September 30 2016, @02:26AM

      by khallow (3766) Subscriber Badge on Friday September 30 2016, @02:26AM (#408209) Journal

      Option 1, carry hydrogen and oxygen precracked in tanks and light it up. Option 2, carry the same mass as water plus solar collectors and the equipment to crack it and then light it up.

      Two things. First, consider the density of hydrogen versus the density of hydrogen in water. The densest form of pure hydrogen is liquid hydrogen which has roughly 70 kg of hydrogen per cubic meter. In comparison, water has about 110 kg of hydrogen per cubic meter. Liquid oxygen is better (1,100 kg of oxygen per cubic meter versus about 900 kg per cubic meter), but it remains that water is a denser way to store the hydrogen and oxygen you need for combustion than storing them separately. When you also add in that you don't need cryogenic storage for water, then it's a huge win in terms of the tank mass and plumbing needed to lift it to space.

      • (Score: 0) by Anonymous Coward on Friday September 30 2016, @07:36AM

        by Anonymous Coward on Friday September 30 2016, @07:36AM (#408277)

        A good point, but then you have to get the power to split the water.

        • (Score: 2) by Geotti on Friday September 30 2016, @04:26PM

          by Geotti (1146) on Friday September 30 2016, @04:26PM (#408429) Journal

          Just carry a portable nuclear reactor with you?

    • (Score: 0) by Anonymous Coward on Friday September 30 2016, @02:11PM

      by Anonymous Coward on Friday September 30 2016, @02:11PM (#408381)

      Careful there -- tanks have considerable mass themselve. One water tank and two tiny propellant tanks, vs. two big cryo tanks, that's quite possibly a mass savings, if the tiny tanks are small enough. Electrolysis equipment adds mass, so at least initially it's almost certainly a net loss, but it's conceivable that we could refine the electrolysis gear such that it's a win for some missions.

      I expect this to make the most sense on long missions with multiple Oberth maneuvers*, such as a Voyager sequel (but with extra fuel and time replacing the favorable alignment of planets). You use boosters with separate propellants to get to Earth escape; then the spacecraft proper can use sunlight to slowly convert water to propellant while coasting to the next flyby. Burn it all, repeat. Because you need a relatively small portion of the propellant at any one time, your separated propellant tanks are small; because you have months or years to fill them each time, you don't need a huge solar array. (In fact, given a PV array sized for peak power demands when active, you may already have enough spare capacity built in to produce adequate propellant while the vehicle is mostly dormant.)

      *or other occasional burns, but if at least some of them aren't exploiting the Oberth effect, you're probably better off using an ion propulsion setup than a chemical rocket with any sort of fuel supply. Especially for the two most obvious such missions, exploring the asteroid belt, or a gas giant's satellites.

    • (Score: 0) by Anonymous Coward on Saturday October 01 2016, @09:49PM

      by Anonymous Coward on Saturday October 01 2016, @09:49PM (#408877)

      You admonish us to do the math, but fail to do it yourself. Or if you actually have, can we see your working please?

      I'm sure the folk behind this project have done theirs, and no doubt it is at least favorable enough to warrant a practical test.

      • (Score: 2) by jmorris on Saturday October 01 2016, @11:46PM

        by jmorris (4844) on Saturday October 01 2016, @11:46PM (#408906)

        Should have been obvious that math wasn't really required here, simple logic would suffice. The fuel mass in both scenarios is exactly equal, one needs to keep the components cold which is actually easy in space, the other must warm water to the liquid state. The water option needs a bigger solar collector plus equipment to crack the water and a small storage for cracked fuel, making it the obviously more massive option. If the goal is to eventually harvest fuel out in space, it might be useful though. Assuming we don't build fixed cracking / fueling stations at places with ice available.