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  1. Avatar Mad Rocket Scientist says:

    I love the Dr. Horrible pic on the front page & the theme song at the end!Report

  2. Avatar greginak says:

    Gah…The anti-GMO really knows how to make their arguments poorly. Not that i think they have a good argument but they make a weak argument poorly. They must have the same consultants as PETA and the anti-vax crowd.

    Brin’s blog is interesting. If the world is ever running short of ego supply i think he could support some small countries, but he makes some good points.

    The biggest problem with moving forward with nukes, even more then a not completely unreasonable NIMBY feeling, is the fed’s will not be allowed to provide the funding the Nuke industry to get going. Were never going to get more nukes w/o some Fed push.Report

    • Avatar Mad Rocket Scientist says:

      Yeah, Brin really does like himself, but if you can ignore the Ego splattered everywhere, he has some interesting ideas. Things at least worth thinking about.Report

    • Avatar KatherineMW says:

      The anti-GMO folks are infuriating. It’s frustrating, because their scientific arguments are 100% bunk, but it’s true that a lot of Monsanto’s corporate actions are deeply unethical. There’s no middle ground, though – in any argument or policy debate, you end up either on the side of the anti-science Frankenfood nuts, or on the side of Monsanto. And I like neither of them.Report

      • Avatar Rod says:

        The real problem here is that GMO isn’t just one thing that we can judge as good or ill. A lot of it is good, providing higher yielding crops that are resistant to drought and disease or producing cool things like iodine-enhanced rice. But it also produces stuff like BT-corn, the Terminator gene, and Round-Up Ready crops that produce fantastic profits for the ag companies but not so much for farmers or conumers, or that are harmful to nature.

        Big Pharma is the same way. Lifesaving drugs: check. Fourteen me-too’s of Viagra: check. Tweaked versions of existing drugs solely to extend patents: you bet.Report

      • Avatar North says:

        Yeah people who with one breath talk about the established scientific consensus on AGW with reverence and respect and then flip around and inveigle about GMO’s make me want to chase them around with a bat.Report

      • Avatar Mad Rocket Scientist says:


      • Avatar Glyph says:

        Why do we assume they are Chiropteraphobic?Report

      • Avatar Brandon Berg says:

        Fourteen me-too’s of Viagra: check.

        Heh. Anti-impotence drugs are funny because I’m not impotent.Report

      • Avatar Kim says:

        Yes, that is the SANE approach. Monstersanto is evil (note: it’s a corporation. of course it’s self interested.), and is fairly close to destroying the world (10 steps away — betcha Alcoa’s at least 30, if not more. How do you destroy the world with aluminum anyway??).

        However, golden rice and other tech like that is going to be crucial for the new millenium (including salt resistant crops).Report

  3. Avatar Jim Heffman says:

    The other issue with aluminum is that it’s brittle when compared to steel; it doesn’t bend very far before it snaps.

    When people talk about “strength”, they’re often actually talking about stiffness. They push on something, it doesn’t bend much, they say “wow that’s strong!”. But in engineering terms, “strength” means the ability to accept load without undergoing permanent deformation or rupture.

    I always describe it as “glass versus rubber”. A glass rod won’t curve much when you try to bend it–until it snaps. A rubber rod will curve quite a lot, but you can probably put more actual force into bending the rubber rod than the glass rod. Rubber is strong, glass is stiff.

    So a structure made of aluminum might be as *stiff* as a structure made of steel, but it wouldn’t necessarily be as *strong*.

    Oh, why do they use it for airplanes? Well, it turns out that for an airplane, the basic shape is as important as the weight; aerodynamics tell you what dimensions your wings and fuselage need to have, and how far out the tail has to go. Given these requirements, you want the lightest material possible that can handle the job, which is how people end up using aluminum. For internal components which are purely structural, designers will often go back to steel.Report

    • Avatar Mad Rocket Scientist says:

      That is why we make alloys. Pure Aluminum is about as useful as pure Iron. But start mixing in some stuff, and we can start making some very interesting trade offs.

      As for Aluminum, have you ever seen this video?

      A straight steel bar versus a straight Aluminum alloy bar may not be a contest with regard to yield strength, but that is only part of the equation. The shapes we give those materials matters, a lot, and in the end, if we can blend & shape aluminum such that it gives us the same overall performance as steel for less over all weight, then we should.Report

    • Avatar morat20 says:

      Do you know how many aluminum alloys there are? Admittedly ,I work in the aerospace sector so I get to hear about engineers gabbing about new aluminum alloys all the time.

      From what I gather, if you need something, there’s an alloy for it. 🙂

      Of course right now the buzz is with composites of some sort. Lots of jawing about new composites and stress modelling on them.

      Apparently launching and returning something from space is quite an interesting experience. Heat, vibration, stress, intense cold, more heat, pressure at all sorts of angles…those guys get excited at a new alloy, material, or concept.Report

      • Avatar Mad Rocket Scientist says:

        I give you, MATWEB!!. Behold all the commercially available alloys of Aluminum and everything else!

        I used to work in Aerospace (still do, kinda, depending on the customer). Nothing puts our materials to the test the way a space launch does. The extreme cold can make the strongest steel as brittle as glass, while the heat of re-entry, or even sitting in direct sunlight, can turn materials to slag, and that is even before we talk about what the rapid change in temperature from launch, re-entry, and even moving from shadow to light can do to a material (tempering it in an unexpected way, or removing the temper, etc.).

        Perhaps I should have gone into it, but the beauty & headache of composites is the fact that they do not have the crystalline structure of a metal, nor the disordered malleability of plastics, but rather a composite collection of both… kinda… sorta… but in strange ways that makes them a devil to model using handbook methods. Even Finite Element computer simulations can have a hard time getting it right. And when they fail, they don’t do expected things like suffer plastic deformation or fracture, but rather they de-laminate and lose strength.

        And don’t even get me started on ceramics, or metal/plastic/ceramic composites.

        Let’s just say that over the past 30+ years, materials science has gotten all sorts of interesting.Report

      • Avatar Russell M says:

        I am still waiting for transparent Aluminum.


      • Avatar Mad Rocket Scientist says:


        The correct term is “sapphire”Report

    • Avatar Kim says:

      Steel? Which steel? All steel?
      The sharpest knife is brittle.Report

  4. Avatar Will Truman says:

    This week’s Linky Friday just got way upstaged…Report

  5. Avatar Francis says:

    Just because I’m feeling grouchy this week: I’d change “So far, Carbon gives us” to “So far, Pure Carbon gives us”.

    Because once you start adding other atoms (like hydrogen, oxygen and/or nitrogen), your list gets just a little longer. (does a complete list of all known organic compounds even exist?)Report

  6. Avatar Burt Likko says:

    I was just wondering the other day why airplanes are not made out of graphene. I understand the problem with the failure of the material, having worked on a products liability case involving the sudden, catastrophic failure of a product made out of graphene.

    If the material fails, you cannot take it to the body shop and have the dents hammered the dents out. The entire panel will need to be replaced. And, if the material fails, it will fail in a manner that is effectively instant, and catastrophic. If you were to build an airplane out of this material, a crack in the wing would appear instantly and without warning from the pilots perspective. That does not give the pilot much time to react, change flight patterns or altitude, or otherwise do something to enhance safety. That’s not to say that a steel wing’s failure is a particularly good thing either, but because the process happened slower, it may be easier in most situations for the Pilot to compensate.

    With all that said, it still seems to me that viable design choices could be made incorporating some kind of carbon-based rather than steel-based material. It has better tensile strength, and is lighter. So the big disappointment here is reading that the reason that this material has not been incorporated is not a function of engineering or economics, but rather a failure of imagination on the part of the designers.Report

    • Avatar Mad Rocket Scientist says:

      Are you sure you are talking about graphene? Much like carbon nanotubes, it is a material that is still very much in the research phase, and not something approved for use in any large structures.Report

      • Avatar Burt Likko says:

        Maybe I picked the wrong noun. Carbon weave, applied in layers with varying angles of the grain, like plywood, for extra strength. I helped out once on a case involving bicycle parts made out of it that failed catastrophically, causing injury to my client. I recall deposing a materials scientist who insisted that the material did not fissure “instantly” because the failure really took about one ten-thousandth of a second. “Go ahead and be right that way in front of the jury,” I thought. “You can be technically correct, and I can get rich after the jury punishes your client for your arrogance. We’ll both win.”Report

      • Avatar Mad Rocket Scientist says:

        That is Carbon Fiber Reinforced Plastic (CFRP).

        See below.Report

      • Avatar Burt Likko says:

        I could have sworn the term was something that sounded like but was not exactly “graphite” but I will not quibble my fallible memory against the knowledge of a subject matter expert.Report

      • Avatar Glyph says:

        @burt-likko @mad-rocket-scientist – it might have been a marketing thing – IIRC, graphene IS being marketed as a component in tennis rackets and skis (and, presumably, bikes etc.) but maybe as an infinitesimal, irrelevant component mostly placed somewhere in there for marketing pizazz.Report

      • Avatar Mad Rocket Scientist says:

        OK then. For clarity

        Graphene (TM) is a CFRP.

        Graphene (no TM) is a sheet of carbon atoms one molecule thick.Report

    • Avatar Mad Rocket Scientist says:

      Also, the failure of the primary structure of a wing during flight is almost always catastrophic. A pilot may be able to compensate for the loss of a control surface, or a wingtip, but a failure of the main wing box, such that a pilot would notice during a flight, means the wing just tore off.

      This is why planes are carefully inspected on the ground, so such impending failures can be caught & corrected.

      As for designing with composites over metals, bear in mind that we have centuries of institutional experience with metal, but only decades with modern high strength composites (except concrete). It’s uncharted territory in a lot of ways, where the bulk of experience is held by those in the racing & experimental aircraft industries (who operate on the cutting edge & free from stagnant regulatory environments).Report

      • Avatar morat20 says:

        Rockets. 🙂 Seriously, NASA — and now SpaceX and other private concerns (which, to be honest, use a LOT of NASA’s institutional experience, data, and methods) — do a lot of cutting edge stuff.

        They have to. Space is unforgiving, launches are harsh and high stress, and weight is expensive.

        Military runs a second place to that — pretty much every commercial airplane out there was designed, inspected, or certified using tools (hardware or software) derived from either NASA or the Air Force’s own internal tools, methods, and hardware.Report

      • Avatar Mad Rocket Scientist says:

        True, but both NASA (what is left of it) & the Military are still exploring what can be done with composites, and the institutional knowledge is still pretty much locked down either through lack of engineer migration, or security classifications (lots of engineering information is classified for no good reason aside from the fact that it is used on a classified project).Report

      • Avatar Kim says:

        oh, hell yeah, there’s ALWAYS a reason to classify your supply lines.Report

      • Avatar morat20 says:

        True, although NASA is pretty good about flowing materials knowledge out — at least if you’re domestic and have signed a few slips of paper. 🙂

        Still, NASA is still toying with composites in the lab. I understand they’re being used in places (commercial and otherwise) but that it’s still very much a developing concept.

        Materials is big stuff. I was shocked when I realized how much a material dictates engineering constraints and design.I mean, I figured aluminum and steel was steel, how much could various alloys really differ? 🙂Report

      • Avatar Michael Cain says:

        Good piece — I’ve said for years that exciting developments were coming out of materials science, particularly understanding what happens at nano scales.

        One consideration, though, is that composites and exotic alloys are very much a developed-world thing, given — as you mentioned — the difficulties of rework or repair. There’s almost nowhere in the world that my clunky old carbon steel bicycle frame couldn’t be repaired with relative ease. The repair might not be pretty, but it would be reliable. My newer lighter aluminum bicycle frame, not so much. And if I were willing to pop for a carbon-fiber frame, even less so.Report

  7. Avatar J@m3z Aitch says:

    Thanks, MRS. Very interesting stuff.Report

  8. Avatar James K says:

    Good stuff MRS, the fusion break-even is particularly interesting. Being a policy nihilist when it comes to Climate Change, the only hope I have is that science will come to the rescue.Report

    • Avatar Michael Cain says:

      Just to pick a nit, you have to stretch the definition of break-even to claim that it was achieved. The energy released was slightly greater than the amount of energy delivered to the target. However, total energy input to the process is 8-10 times the amount delivered due to assorted system losses, so they’re still an order of magnitude short of positive net energy. Then there’s the problem of generating electricity from the process. Fundamentally it’s still just a heat source, so will undoubtedly heat a working fluid to drive a turbine. Today’s fission reactors average about 33% thermal efficiency. Gen IV fission reactors hope to make 45% by running either very hot or at very high pressures.

      I’m more concerned about capital constraints and timing. For the US, over the next 30 years most of the commercial fission power plants are going to reach the end of their license extensions and (IMO) those won’t be extended again, given the problems so many of them seem to be experiencing. If we’re going to do something about CO2 emissions, the coal-powered fleet needs to be replaced (at least the heat source) in the same period. And both are going to be replaced with something other than fusion because fusion is still at least 25 years away (based on the ITER timetable). We’re going to either solve (or not solve) the problem without fusion — and all that shiny new gear makes it much harder for fusion to get a toehold in the commercial market.Report

      • Avatar Mad Rocket Scientist says:

        It’s a valid nit to pick. I still think it is worth mentioning because it is a milestone, and that means we are at least continuing to advance the technology.

        Either way, I do a little happy dance.Report

      • Avatar North says:

        I’m dancing right there with you MRS. Nuclear is the closest thing in this mundane world to magic for me. I’m not a spiritual man but when I think about the foundational matter/energy process of the universe I can feel a tingle of awe running up my spine.Report

      • Avatar Glyph says:

        My wife thought it was kinda weird, but when we were driving cross-country and I realized that we were going to be near enough to Trinity to make one of the biannual days when it’s open to the public, I made sure we went. A pilgrimage of sorts.

        So yeah, there is something that feels almost “holy” about it.Report

      • Avatar Michael Cain says:

        I’m pleased that there are still people enthused about fusion. It would certainly help solve the electricity supply problems I anticipate, at least if the tech is affordable and arrives in a timely fashion.

        In the meantime, I think we in the US get to watch two very different approaches to the problem. The Western Interconnect region of the US looks to be headed down a path more like Germany’s: existent hydro (with potential for considerably more if they so desire), growing wind and solar, commitment made many years back to natural gas rather than coal, and shrinking nuclear fleet (down to six reactors, and if it were put to a vote, California and Washington would probably close three more). The Eastern Interconnect is (IMO) unlikely to take that same course, just because their renewable and natural gas resources are so much smaller relative to their aggregate demand.Report

  9. Avatar Mike Schilling says:

    That article on Q-glass makes it sound exactly like Ice-9,Report

  10. Avatar Kolohe says:

    “Practical applications for such a material are not readily apparent”

    transporting humpback whales?

    “I don’t think I can adequately express to anyone here just how incredibly difficult it is to do something like that with a rocket.”

    well, it’s not like it’s r…

    oh, right.Report

  11. Avatar North says:

    I knew, -knew- when Germany decided to mothball their nuclear plants after Fukushima that the huns were going to end up burning coal and oil to replace it. How unpleasant to be proven right with a nice turd cherry of massively increased costs to their poor for electricity on top.

    Honestly, the whole AGW crowds antinuclear fetish makes me want to tune them out. They’re clearly not serious. Here’s hoping fusion comes through in time to bail us out because fossil fuel independence sure ain’t gonna come on the blades of a fishing windmill.

    I hope I live long enough to see a space elevator built. I really honestly hope that. I can shuffle off to the beyond with some confidence that the species has a decent shot of escaping the Terran gravity well if they manage to build one of those things.Report

    • Avatar morat20 says:

      I knew, -knew- when Germany decided to mothball their nuclear plants after Fukushima

      You realize that is as historically accurate a description of Germany’s nuclear policy as claiming Paul Simon was the first man to land on the moon, right?

      Germany made the decision to move off nuclear power in 2000. In 2009, Merkel wanted to EXTEND the phase out (extend the lives of currently operating plants by 8 to 15 years), and then reversed course after Fukushima and basically went ahead with the (already planned) phase out — mostly because her extension plans were unpopular enough BEFORE Fukuushima.

      So Germany’s phase-out had nothing to do with Japan. Period. Unless the even travelled backwards through time 11 years.Report

      • Avatar North says:

        A fair point Morat, but as you note Japan’s disaster did accelerate the nuclear phase out, or at least prevent it from being strung out longer. Considering the problems they’re having I’d think Germany would have benefitted from having that capacity available when the wind stopped blowing.Report

      • Avatar morat20 says:

        Not..exactly. German politics on this are a bit murky, and while I have heard (at length!) the entire story from local sources (ie: German relatives of mine), I’m a bit fuzzy as to their politics and how it might bias them. Germany’s political system is, like the rest of Europe’s, a bit different. So take with a grain of salt, but here is the synposis I’ve gotten:

        1) Germany was and has been really serious about getting rid of nuclear power plants since even before 2000.
        2) Germans are pragmatic — they basically decided not to build new nuke plants (but not to shutter the old ones) and let the older ones phase out as their operating lifespan ended. (This included no extensions through maintenance, re certification,etc)
        3) This was Not Popular with several large-scale businesses (IE: The people who build, operate, run, and sell nuclear power in Germany — or who would like to).
        4) This led to a several years of arguing, wherein the German public was pretty solidly “No, no new nukes. Phase them out and replace them” and lobbyists being very firmly “Nuclear is clean and awesome and the public doesn’t really care that much”.
        5) The pro-nuke side lost.
        6) Then Merkle was elected, and she’s quite friendly with the energy segment and started pushing for nuke plant extensions — preparatory to revisiting the issue (This is complicated by the parliamentary nature of German politics. It’s not so much Merkle personally but her party and the controlling elements of a very wide coalition that they needed to put together a majority. )
        7) Then Japan happened, and it became too politically costly to keep fighting the fight, so she reversed course — and like every politician EVER who suddenly was on the wrong side of the public and stripped of call cover, she went overboard to prove she’d “learned”.

        The German public was and is still heavily in favor of a phase-out. Nobody but a few crazies wanted to turn plants off. They just wanted to replace them with something non-nuclear (and fairly clean) as opposed to replacing them with new nuclear plants.

        Merkle’s overreaction was due to having been pushing FOR extensions of aging plants right as Japan happened.

        Even then, it’s been pretty modest. A drop of something like 0.5% of all German electricity production — nukes fell from like 16% to 15.5%, they’re already less than solar and wind as a % of energy generation.

        Germans have been planning for this for over a decade — a political overreaction through a spanner in the works, but it’s gonna be a temporary blip. German’s aren’t effing stupid — they know what baseline load is and how to generate it, and their plan was never “get rid of nukes and then hope for sunshine” or “get rid of nukes and build dirty coal plants to replace them”.Report

      • Avatar North says:

        I appreciate your insight, that sounds eminantly plausible.Report

      • Avatar Mad Rocket Scientist says:

        @morat20 @north
        More recent article from New Scientist.

        Done with the best of intentions, I am sure.Report

    • Avatar Mad Rocket Scientist says:

      Of course, if we built a space elevator, we could potentially produce enough power through the elevator to satisfy a good chunk of the world.Report

      • Avatar morat20 says:

        I knew a guy whose company was working on space elevators. Lab stuff (materials) and basic engineering concepts. Preliminary study stuff. What can we do, what problems do we face, what roadblocks, etc.

        Last I heard — and this was four or five years ago — they had two major roadblocks, one they expected to sort itself and one they were stuck on.

        The first was the material — they had a material that would work (some carbon nano-tube stuff) but they needed something to be at least a foot long and they could only grow it three inches or so. They figured that was just a matter of time to sort out.

        The other was a bigger problem. IIRC, they said that there was a lengthy period during the proposed construction wherein the ribbon would be too small to handle a micro-meteorite impact but too big to avoid getting hit. Prior to that phase, the ribbon was small enough that the odds of impact were low. After that phase, the ribbon could take the hits (as the next crawler up would repair it). But during? Bye-bye ribbon.

        They considered that the serious engineering challenge.Report

      • Avatar Glyph says:

        I used to wonder how they’d prevent sabotage to the ribbons, but I guess drones mostly sort that problem out.Report

      • Avatar Mad Rocket Scientist says:


        Very true, the first step will be clearing the area around the ribbons as they feed out, & then keeping it clear. Once in place, the elevators themselves can function as ribbon repair bots, locating and fixing holes as they go up & down. And yes, nanotubes will probably do it, once we figure out how to grow them at industrial scales (I give that less than a decade).


        One way to limit sabotage is by placing the elevator out in the ocean. The base has to be on the equator, and there is not a lot of land along the equator that has stable political realities. Once there, the only way to sabotage it is by plane, and by the time we can build one of these,we should be able to enforce a no-fly zone around it rather nicely using drones and turrets. Also, once complete, it will be very difficult to cut one of the cables without a lot of explosives (that nanotube ribbon is crazy tough!).

        Not that we don’t have a shortage of endlessly inventive nutjobs who will be happy to try…Report

      • Avatar North says:

        MRS, would that be via solar harvested in raw and unfiltered in the orbital environment and then transmitted down the ribbon to earth or via some other interesting means?

        I’d think that a space elevator ribbon would be a pretty difficult target. Wouldn’t the ribbon just cut through a plane if you rammed one into it (that’s assuming you somehow evaded the arial exclusion defenses and managed to hit this little ribbon while dodging drones and AA fire)?

        How solidly on the equator does this puppy have to be again? I’m spacing (hah). Is Singapore close enough? Indonesia could be a lot better as a host nation but it is not a terrible venue.Report

      • Avatar Glyph says:

        solar harvested in raw and unfiltered in the orbital environment

        When it comes to solar, buy organic. You don’t want hormones and stuff in there.Report

      • Avatar morat20 says:

        IE, the proposed ribbon is about a foot wide, an inch or three thick, and something like twice the diameter of the Earth long. 🙂Report

      • Avatar Mad Rocket Scientist says:

        Given: The earth has a very powerful magnetic field encircling it that does not rotate at the same rate as the earth.
        Given: If you want to induce an electrical current in a conductor, you move it through a magnetic field.
        Given: Carbon nano-tubes are extremely conductive

        So if I have a conductive cable stretching hundreds, even thousands of miles through a massive magnetic field, I betcha I can juice up my phone.

        And a couple of large first world countries.

        I think you are having just way too much fun in the comments here…Report

      • Avatar Glyph says:

        @mad-rocket-scientist – sorry, I’ll show myself out. I should be working anyway, I just feel unmotivated today.Report

      • Avatar Mad Rocket Scientist says:


        The ribbons will be pretty substantial, not mono-wire. Add enough energy to one & it will snap. An elevator would have to be defended against nutjobs.

        Also, the cable will reach to geosynch orbit (35,786 km), which is where the hub station would be. Then you would need another 35,786 km of cable payed out into space and attached to a big damn counterweight (which could be another space station itself, with elevators). The magnetosphere extends up towards geosynch.

        It needs to be on the equator (+- a few km at best). since that is the rotating plane. Not a ton of wiggle room on that front. Luckily the ocean is full of Mountain ranges and we could anchor a base to the tops of one of those (say, south of Hawaii).Report

      • Avatar Mad Rocket Scientist says:

        No worries, just acknowledging that you are on fire.Report

      • Avatar North says:

        MRS, I’m transported by that explanation. So simply by standing (being suspended?) there a space elevator would have power generation potential?

        Thanks for the clarification. I stand by the assertion that a slender nonotube ribbon should be pretty easy to defend against non-military equipped crackpots (though I concede that an explosive armed drone might do the trick).Report

      • Avatar Mad Rocket Scientist says:


        The elevator cars would have nothing to do with power generation. The fact that the conductive cables/ribbons are cutting through a magnetic field at a right angle is all it takes (field lines go north-south, the cables extend away from earth at the equator and thus intersect the field lines at 90 degrees – ergo – POWER!

        As for sabotage, I don’t have to hit the ribbon, just target one of the cars with a big enough warhead.Report

      • Avatar morat20 says:

        NASA has experimented with power production using tethers. IIRC, their first experiment shorted out their system. The tether they deployed generated far, far, FAR more electricity than they’d thought.Report

      • Avatar Burt Likko says:

        How fun! I’d always sort of thought a space elevator could be built in Brazil or Ecuador, which seem stable enough politically. It never occurred to me that a platform could be built at sea, or that the elevator would be a massive source of electricity. How might the power get conducted from the base of the elevator to outlying industrialized areas? Copper wire has low resistance compared to a lot of other material, but it’s not zero, and wouldn’t existing grid networks have to be upgraded to handle the massive capacity? Do we have to assume quasi-superconducting wires made out of unobtanium?Report

      • Avatar Burt Likko says:

        Oh, and do these power-generating tethers have to be at the equator, necessarily? Would a counterweight in geosynchronous orbit at the end of the tether keep a non-equatorial tether stable? We’d need terrific tensile strength, but…Report

      • Avatar Michael Cain says:

        For some reason, the thing I always think of about a space elevator is that if the elevator car averages a thousand miles per hour, the trip up to geostationary orbit takes a bit over 22 hours. One of Burt’s bullet trains running at its top speed of 220 mph would take something over four days to get there. Some more recent studies suggest that to guarantee stability of the cable, elevator cars may have to move at relatively low speeds.

        People worrying about strikes within the atmosphere are worrying about the wrong thing. Given a large number of satellites (and other debris) in low-earth orbit, each crossing the equator twice per orbit, it’s only a matter of time before one of them hits the cable. Sure, it’s a low-probability event — but eventually one of the satellites gets lucky, and with a velocity difference measured in km/sec, it’s unlikely that the cable will survive.Report

      • Avatar Glyph says:

        NASA has experimented with power production using tethers. IIRC, their first experiment shorted out their system. The tether they deployed generated far, far, FAR more electricity than they’d thought.

        “First, imagine a gigantic Ben Franklin and an enormous kite. Then, imagine a brass key thirty-five feet long, weighing approximately six hundred pounds.”Report

      • Avatar Mad Rocket Scientist says:


        Copper wire could do it, as the amount of power from a space tether would be enormous, so loses would be of little concern. Heck, we might even be able to do broadcast power (wireless), since that technology continues to advance. You could also just store the power by converting to hydrogen through the electrolysis of seawater at the anchor site, pump the H2 into ships, and send it where ever you need it (since fuel cells will become commercially viable in the next decade or so, this is probably the best scenario).

        Any tether that reaches into space must be within a few degrees of latitude of the equator, since that is the plane of rotation (i.e. perpendicular to the axis of rotation). The further you go from the equator, the more it will bend toward the equator, and the allowable bend to where it falls back to earth is pretty small.Report

      • Avatar Mad Rocket Scientist says:


        Yes, the cars would probably take about 8-10 hours to climb to the hub station, with quite a bit of that spent in the atmosphere, since drag would be a factor. Once free of the atmosphere, the car could accelerate constantly along the cable to a rather high rate of speed, then decelerate safely.

        And yes, satellite traffic would have to be altered a great deal, and we’d have to get a lot better about tracking debris, etc, and have a way to clear it, and have a way for cars to survive impacts with debris, etc.

        Nobody said it would be easy.

        Now, once we know how to do something like this, there is no reason why we could only have one. I could easily see 4 such platforms around the earth, each providing power to the planet, and each hub station acting as one massive geostationary satellite for one quarter of the sky, with weather & communications & surveillance nodes all over the underside, so we could clear the geostationary orbits of most of the traffic.Report

      • Avatar Burt Likko says:

        Last question, I promise. (I hope they’re good questions.)

        Doesn’t the Earth’s axis of rotation wobble over time? Or is that just the angle as compared to the plane of solar rotation? How long does that take, and would that affect the stability of the hypothetical elevator?Report

      • Avatar Michael Cain says:

        Yes, there are wobbles, but small ones — think a few meters per year max. Some sources: gravitational pull from other planets and seasonal changes in location of mass on the surface of the planet. Put thrusters on the body in geostationary orbit (and perhaps on the counterweight); you may need them anyway to damp oscillations from other sources. The good news is that lifting reaction mass into position isn’t a problem, and if there’s plenty of electricity available you’re not limited to chemical reactions.Report

      • Avatar North says:

        When you imagine what we do now with tiny satellites composed of the lightest material available and lofted into orbit at enormous expense more or less set adrift and then left to their own devices the idea of a stationary location that can secure much greater amounts of equipment and also allows for visits to do maintenance or upgrades… it’d probably be to the development of space what transistors were to computation.Report

      • Avatar Mad Rocket Scientist says:

        They are good questions, no worries!
        @michael-cain is right, there is a bit of wobble about the axis, but it very small & it takes centuries to move enough to be a problem. Plenty of time to figure out what to do about it.

        The two big leaps such a platform would give us is a stable base for microgravity manufacturing, as well as a good spot from which to build & launch spacecraft that don’t have to be designed to survive re-entry or otherwise operate in an atmosphere. Such would open the door for us to affordably exploit the moon, as well as near earth asteroids.Report

  12. Avatar Kim says:

    Looks like it was bonding that was the issue… (at least that’s what they’ve fixed).Report

    • Avatar Michael Cain says:

      Speaking of adhesive bonds, one of the things that always gets me is just how much of a late-generation jetliner is glued together rather than using mechanical fasteners. It’s one of those things I hate to think about when I fly. I know intellectually that modern adhesives are amazing things, but emotionally I want bolts. Really, really big bolts.Report

      • Avatar Mad Rocket Scientist says:

        Usually adhesive is used to fix parts together, & then a fastener is used to make the join permanent. But ultimately it depends on the stresses involved at the joint in question. If an adhesive can do it, and failure is non-critical, why add more weight? I’ve seen small gliders & single seat aircraft that are mostly glued together.Report

      • Avatar Alan Scott says:

        My Uncle is an airplane mechanic for a commercial airline. According to him, a surprisingly large portion of his job consists of temporary fixes using fancy duct tape.Report

  13. Avatar Francis says:

    Since drones were mentioned upthread and are in the news this week, I have the following question for the group:

    If we allow the broad domestic use of drones, how do we keep terrorists from flying drones into the mouth of jet engines at take-off?Report

    • Avatar Glyph says:

      Anti-drone drones?Report

    • Avatar Stillwater says:

      how do we keep terrorists from flying drones into the mouth of jet engines at take-off?

      Weaponize them?Report

    • Avatar Burt Likko says:

      This strikes me as an excellent question.Report

    • Avatar Mad Rocket Scientist says:


      Jet engines are pretty tough. A drone large enough to choke out a turbine will show on radar. A drone small enough to avoid radar will just become crispy confetti. It will also have a hell of a time getting close enough to the intake in time to get ingested in the first place. I mean, I know airliners look like they are moving slow during take off, but they are doing 150+ mph. It’s going to take practice to get your drone ingested.

      Now if they attach an explosive…Report

      • Avatar Stillwater says:

        Which is why we need to weaponize those jets!Report

      • Avatar Mad Rocket Scientist says:

        Point-Defense lasers on the intakes.

        Everytime a flock of birds gets too close, there is a pretty light show and everyone starts to wonder where the KFC is.Report

      • Avatar Francis says:

        I’m curious about the toughness of jet engines; Sullenberger had to put his plane into the Hudson from a single bird strike. And while jets do move fast, they also follow a pretty reliable path at take-off. I just can’t imagine that it would be all that hard to put a video camera on a drone, get it to the right altitude off the end of the runway, and fly it into the mouth of the engine. Strap some ammonium nitrate to the drone and let’s see what happens.Report

      • Avatar Mad Rocket Scientist says:

        Back in my youth, I was a gas turbine mechanic for the US Navy. The number of things I’ve seen a jet engine suck up and keep on spinning is downright impressive (up to and including people). And the stories I’ve heard even more so. Granted, when a turbine ingests something big enough, it’ll probably get pulled & serviced, but chances are good it’ll keep running, or at least be re-startable.

        Sullenberger sucked in 4 geese (which are big enough to show on radar), two per engine, which didn’t actually hurt the engines too much*, just caused a flameout. The problem was he didn’t have enough time to restart both of the engines before he was out of altitude. Also, once a jet is in the air, even if still climbing, one engine is sufficient to maintain level flight and land, so a flameout during take-off is only dangerous during rotation and the initial lift off, when the main gear first leave the ground. Most aircraft have enough altitude by the time they hit the end of the runway to level off, circle around, and land.

        To recap, a drone large enough to choke a turbine (and thus large enough to show on radar) will make life exciting for some people, but probably not cause a crash. Unless it’s got an explosive payload. A big enough bomb could do enough damage to risk an actual crash. Although, keep in mind that turbines are known to tear themselves apart during operation, which is known as rotor burst, and airliners are designed to absorb the damage from a rotor burst and still land safely, so it would have to be big enough of a bomb to do more than just cause a rotor burst, and if that is the case,if it is that big, it’ll need to be on a big drone, and it won’t need to get sucked into an engine, just close enough to the nacelle or the wing to tear out the main structure.

        Of course, we have drones like that, we call them “missiles”.

        *something the size of a goose could damage some of the compressor or turbine blades, but that won’t stop a turbine necessarily. I’ve seen turbines where the blades are almost stripped clean keep spinning, even if they long ago stopped producing any real power, and will never restart.Report

      • Avatar Francis says:

        One less thing to worry about. Thanks for the comment.Report

      • Avatar morat20 says:

        Keep in mind, commercial airlines are built with a specific glide ratio as well — 17-to-1, I think.

        That means any FAA certified airplane MUST, in the total absence of power or propulsion (absolute dead bird) travel laterally 17 feet for every foot it loses in altitude.

        It’s surprisingly hard to crash a modern airplane. They’re designed that way. 🙂Report

      • Avatar Mad Rocket Scientist says:

        As @morat20 said, modern airliners are designed such that one thing going wrong is OK. As a matter of fact, a lot of things going wrong is usually OK. Nowadays, you need to have a cascade failure of all sorts of things in order to down an aircraft that the pilot wants to keep in one piece.

        And don’t forget, airliners are tough, even 737s (remember the Aloha Air flight?). You will need a lot more than a hand-launched drone to do anything more than scare the piss out of everyone.Report

      • Avatar Michael Cain says:

        It’s getting cheaper and cheaper to build a surface-to-air missile/jet drone that could hit a jetliner during takeoff with a few/many pounds of explosive. How long until a billionaire that hates the US funds the development of one? Given the speed of contemporary microprocessors, you could no doubt use a video camera and the software could pick where to hit the plane.

        (Hi, NSA! Yes, it’s me again, discussing terrorist tech.)Report

      • Avatar Patrick says:

        I’m pretty sure I could do this now, if I wanted to. I don’t think it’d even be particularly expensive, given that I could warez most of the things I need from, ah, various low-security places.

        I mean, if I’m gonna blow up a bunch of people, I’m not going to be overly dissuaded from stealing, either.Report

      • Avatar Mad Rocket Scientist says:

        @michael-cain @patrick

        I’m just going to shut up now & let you two talk to the men in dark suits & sunglasses that will be showing up on your doorsteps in 3…2…1…Report

  14. Avatar Mad Rocket Scientist says:

    Materials Primer: (for @burt-likko & anyone else who cares)

    When it comes to Materials, there are a number of properties of interest to engineers. Without going into the nitty gritty, we care primarily about the ability of a material to resist stretching (tensile strength) & squeezing (compression strength) across a specific temperature range. Generally, these properties are consistent across a large temperature range, changing only as the temperature approaches melting or very, very cold. We also care about hardness, fatigue, thermal & electrical properties, etc.

    When we measure how much force a given material can handle in tension or compression*, we look for two things – when does the material elastically deform, and when does it plasticly deform. Elastic deformation means when the force is released, the material will return to it’s original shape. Plastic deformation is also known as yield, and is when the material is permanently deformed & damaged (in a metal or ceramic, the crystalline structure has shifted and assumed a new arrangement, in a polymer, it’s the molecular structure). The elastic deformation range is important, since it tells how much our object can flex, & depending on the application, we may or may not want a lot of flex. The yield, however, is critical, because that is when the excrement hits the rotary air accelerator.

    One we know the basic material properties, the next thing we need is the shape. Shape is very important. The hows & whys is pretty involved & requires a discussion about the various moments of inertia, but suffice it to say, a solid cylindrical bar of steel will behave differently relative to a hollow tube of steel, relative to a solid square bar or tube of steel, relative to a bar shaped like an I-beam, even if each bar is exactly the same length and has the same mass of steel. Even if the cross-sectional area of each bar is the same, they will behave very differently.

    Now, the trick with composites is that they are made of different, disparate materials working in concert (as opposed to an alloy, which while it is made of different materials, it is a cohesive solid structure – if it helps, think of the elements of an alloy undergoing a chemical reaction to create a new material). The two best known composites are concrete & fiberglass. Concrete is a mix of cement (a powdered mixture that when mixed with water undergoes an exothermic chemical reaction to form a solid material that is very brittle) and some aggregate, usually gravel of some fashion. When the cement & gravel combine with water, the brittle cement binds to gravel. The rocks in the gravel provide incredible compressive strength & the cement fixes them in place. To give concrete tensile strength, we add steel bars (sometimes even going so far as to pre-stretch the bars to some degree, hold them stretched like that, then cast them in concrete). Fiberglass is similar in that we take spun fibers of glass & apply them to a surface coated with an epoxy**. The epoxy is also brittle, but when the glass is added, they add considerable tensile strength to the epoxy’s compressive strength, and since the fibers go in every direction, the strength tends to be available in every direction.

    CFRP takes this one step further, and using Carbon Fiber (basically nylon fibers that have been cooked in oxygen free oven until they are something like 99% pure carbon), mats are woven. The mats, being woven with the fibers perpendicular to each other, offers superior tensile strength in two directions (the directions the fibers lay in. To cover additional directions, we impregnate the mats with epoxy and lay another mat on top of the first with the fibers oriented at 45 degrees to the first mat. Now we have strength in 4 directions. Need more strength in more directions, add more mats, repeat as needed. The epoxy locks all the mats into place & shape, and provides a measure of compressive strength (since the fibers have essentially none).

    Now, since CFRP is a series of mats, with different arrangements bound with a resin, it does not behave like a metal, or a homogeneous plastic, or a ceramic. In reality, it behaves like the absolute strongest wood you will ever find. And much like wood, when it fails, it does not bend, but rather it splits along the grain (de-laminates). Once that happens, the strength is compromised, but the failure is not always visually obvious, since the part itself may not be deformed in any obvious way. That does not mean it is hidden until it fails catastrophically, only that a person will have to inspect the part and do some testing to see if it failed (and yes, if it de-laminates internally, you toss it; no fixing that break).

    The engineering challenge is that while we can easily compute the strength of simple shapes formed of CFRP, complex shapes are orders of magnitude more difficult. With metals, if the shape does not conform to a common shape that we know well, we can still model it in a Finite Element code & get an accurate idea for how it will behave (assuming no defects in the material). Composites are not so simply modeled, since the material properties will change with every mat (since we re-oriented the mat by 45 degree, or some other angle), so each mat must be modeled, and then the collection assembled & modeled.

    I am sure by now we have figured out ways to make modeling composites in the computer more straightforward, but since my area is fluids, I’m not always up to speed on the latest in Finite Element techniques & composites modeling (& the guy in my office who would be is not in yet). Still, there is a lot of ground yet to cover with regard to composites, and the population who can be considered to have mastered them is still very small, so in the words of TreeBeard, “Don’t Be Hasty!”

    *I sometimes get asked if there is a measure for bending resistance. The answer is no. Think about it, if you have an I-beam and it starts to bend down, what you are really doing is putting the top of the beam in tension & the bottom in compression. Knowing this, & knowing that forces will be distributed evenly through the material, we can develop an equation that will tell us how much load the beam can handle based upon it’s material, cross sectional shape, length, & how to beam is fixed to something (if it isn’t attached to something, it won’t bend, it’ll just move). There is a whole book filled with these equations called Roarks Formulas for Stress & Strain (currently in it’s 8th edition).

    **epoxy is a generic term for a class of multi-part polymer. The most common is a two part polymer you can buy in any hardware store with brand names like Bondo, JB Weld, and the various clear epoxys that are found in all manner of tubes for about $5. The important bit to remember about an epoxy is that when properly mixed and allowed to cure, the resulting solid is one giant cross-linked molecule that binds anything embedded in it. Epoxy tends to be brittle, but has good tensile & compressive strength. Mixing it with other things helps to compensate for the brittleness.Report

    • Avatar Mad Rocket Scientist says:

      Oh, one more thing. Materials can be brittle, or ductile (and this can change depending on the alloy & the temperature).

      Brittle materials like Aluminum are still very strong & can still flex quite a bit, but when they fail/yield, they tend to break, while ductile materials like Lead will just bend. Alloys can change this property considerably.

      E.g. Iron is very brittle, but add some carbon & a few other things to the molten iron & you get steel, which is very ductile.Report

    • Avatar Kim says:

      Got a bit of a puzzler for ya, since you’re the one who does fluids:
      How, exactly, do you get a 1cm long tear in a vein (a clean tear, like exacto knife clean…)?
      The docs can’t figure it out (odd things aren’t their field)…Report

      • Avatar Mad Rocket Scientist says:

        More of a structural question, and I’m not terribly familiar with how everything in our bodies is built, but I seem to recall that veins have structure that a very fibrous. Stands to reason you aren’t seeing a cut, but a clean split along two fibers that happened to grow parallel.Report

  15. Avatar Patrick says:

    “PS don’t tell the anti-GMO crowd, but vaccines are GMOs!”

    Yeah, there’s enough overlap between the two that this is probably not relevant, anyway.Report

  16. Avatar Kazzy says:

    Why don’t we make roads out of some sort of textured metal? Wouldn’t that save tons on repair and upkeep? The upfront costs would be high, but it’d seem to pay off long-term. Best I can come up with is that metal is non-porous and water would collect on it. It would seem that a drainage system could account for this.

    Why don’t we make tires of solid rubber? It seems insane that flat tires are still an issue. Is it a weight issue?Report

    • Avatar Mad Rocket Scientist says:


      Roads – corrosion is one concern, shifting earth is another, but cost is the biggest. The amount of metal needed to replace even a single highway would suck up a large portion of the yearly production. We’d run out of metal long before we ran out of roads to replace. The vast bulk of concrete & asphalt is rock, and we have an nearly inexhaustible supply of that.

      Tires – Airless tires are on the horizon. I give you, the Tweel!. The reason tires are not made of solid rubber is that solid rubber can not handle the heat & stresses of high speed travel, are very noisy, and offer horrible handling and shock absorption characteristics, plus they deform too readily under load. Galvanized rubber with steel belts and air pressure took care of a lot of that. The tweel is possible now thanks to advances in plastics & rubber that allow us to more precisely formulate for the characteristics we want (thank you modern Chemistry!).Report

  17. Avatar Kazzy says:

    Ooo… another one… are you familiar with oobleck? Or non-Newtonian fluids? How would these work in safety gear? I imagine that you could make a vest with a bladder on the front and back filled with the stuff. When moving slowly, it’d be fluid and move easily with the body. But upon sudden impact, it would harden, absorb the force, and distribute it. Eh? EH???Report

    • Avatar Mad Rocket Scientist says:

      Fluids guy here, so yes, that covers the non-Newtonian one too.

      So, impact protection, see D3o.

      I bet in the next decade, we’ll see bullet proof/resistant outwear made from the next generation of materials like this. No more bulky kevlar.Report