Still a bit off from that, but I’d better get back on the horse. Although, it’ll be a while before I’m quite comfortable un-self-consciously voicing an irrelevancy in mixed company. Which… anything new I contribute might be such an irrelevancy.
Part of it was also that there is, when talking about feminist topics, which this largely-female circle does often, an iron opposition to “derailing,” which is a never-ending phenomenon when hostile or surface-friendly men come in and say things that try to divert discussion from women’s experiences to how “it’s not all men” or to other slants or topics, and insist that the talk now be about what they said, etc. The broad resulting rule of (counter-)attacking derailing, applied in “cannons free” style, is understandable with people who are in waters where they must face endless boarders who want to take over the wheel and steer for a more comfortable-to-themselves continent. Part of what happened, or the beginning, was that—mildly from my friend’s brother, very strongly with this fiery woman—that stringent rule and trained pattern from that embattled context got effectively applied to topics at large and in general (to a thread about Ebola contagion worries versus management), and was triggered by an odd-sounding off-sides remark made about my friend’s brother’s observation about the importance of good public health infrastructure—by a silly sod who completely agreed with him and had not the slightest thought of countering or derailing his point or further discussion of Ebola…
Anyway. Gun-shy. Which makes journal-writing a much safer venue. :-/
I did not expect to be beginning this next entry this way:
When I wrote the ITER entry and the “solutions” entry, I mentioned that I was wondering about that puzzling announcement from Lockheed Martin from 2013 saying they would have a working fusion reactor by 2017. So much like so many other big crankish promises—and yet from such a serious company, and yet so soon…
Well—immediately after I posted the latter, it became no longer just a Google result from back in 2013. Lockheed Martin said it again, with a slightly stretched schedule but not enough that it makes a difference. Launched a glossy web page for it. (Click on it—take a gander at that thing.) All the blogs I read started mentioning Lockheed Martin’s announcement.
So it wasn’t just some Lockheed engineer who got drunk. They are serious.
This hits me two ways—both strongly.
With our energy/climate change/emissions-reduction conundrums, we could really stand to catch an ace about now…
… and, if the Lockheed Martin promise does work out on schedule and by the numbers, we’ll have gotten A THIRTY YEAR JUMP on the fusion implementation schedule that we could otherwise expect if ITER and DEMO worked out.
A THIRTY YEAR JUMP. (And small reactors, adaptable to lots of little theoretical uses immediately. Jiminy Christmas.) Fusion in our time. That is an ace!
This is not something fusion scientists in general have seen as a big potential chink in the armor. As a body, they’re sceptical. So this is an idea quite specific to Lockheed Martin’s SkunkWorks. Which, yes, is a good outfit with a good record, I hear.
But what kills me is that they know what they plan, they know what they’re going to do in the project—and they can talk all they want about how a small design means that they can build through several iterations quickly—but they don’t know and cannot know that the prototype is going to work as expected until they’ve built it and it is working as expected. And they’re talking big now.
What I worry about is that interest in fusion comes in booms and busts. If there’s too high promises about this and they happen to get a lot of publicity, and they can’t make the thing work with their first approach or at all… then suddenly fusion is a matter of gold rushes to find fairy dust. And then funding for the big efforts is in danger of getting a big chop for the next decade or more.
I’d be much more comfortable if Lockheed Martin had just kept quiet until they had a prototype completely working and then said, “Uh… guys?”
And, actually, why are they going public about this now? They say why. Because they’re looking for partners. Which… really they’re looking for people to share the risk.
Yeah. Nice website. Those would be first-rate little gadgets to be cranking out in ten years—or, first-rate doesn’t cover it.
But I’m not feeling mellow… because the ripple-impact of failure means that this is one of those situations that is shaped in such a way that it had better work. And I have seen a few of those. :-(
Now then. I had mentioned in a note that the “solutions” entry almost worked in reverse—when I started writing I was largely tapping my memories of past thinking and investigations , but by the end I was web-researching like mad.
There’s been enough of a pause that now I’m worried that I won’t think of everything I wanted to add next. Let’s see. (Thank you, Bookmarks list.) For one thing, I found current work toward space solar power systems. I had thought the idea was in hibernation, but JAXA, the space agency for resource-poor Japan, is working toward it.
JAXA, who launched the solar sail IKAROS that was the butterfly of my dreams that year. Of Japan, pusher toward robots for the elderly. I love you, wily and sagacious Nipponese. Keep kicking our lazy butts to Bermuda and back.
Yeah, there’s nothing really wrawng with the idea that I could find—just the effort and the myriad engineering problems to be addressed. There is the complication that you do need the space capabilities to actually do something that big, more for bigger, etc. So that is an aspect of a big build effort, a large aspect physically and financially.
I did find an issue—that I am irritably inclined to call a quibble, but I haven’t seen anything about the math or gone into the chemistry, etc., and must be more reserved—where the addition to the atmosphere of all the rocket exhaust plumes from the necessary launches is a factor to be considered in doing this. Maybe. Well, physically, yes it is. Most rockets are using things with exhausts more problematic than just liquid oxygen and liquid hydrogen. And they pass through the high atmosphere venting it, which could have special problems. I should look at it (though I’d be more inclined to think that perhaps certain propellant mixes should be banned). But it reminds me of the real but often, it seems to me, abusable business where a particular route of solution or device is dismissed because of the embodied energy, and therefore emissions or social energy burden, that it would require to make or do the thing. The energy to do it should be factored in, but I’ve seen “nope!” conclusions made where the mention of the embodied energy is seen as the final word—even cancelling out progress in conservation or energy efficiency that would have been the result. In this case, I think there’d have to be an extraordinary problem with rocket-propulsion gases in particular to outweigh zero-emissions electricity from space for hundreds or thousands of years.
We should do it.
(Considering that, for one thing, that old phrase that used to attach to the dream of fusion power, that electricity would be “too cheap to meter”… it’s very unlikely with fusion, or with any imaginable fuel or power source—unless you just happened to put enough space solar panels out for it. Then you could have it.)
EDIT: It’s apparent to me, so I was slow to think that it might not be obvious to any Reader: When I say “our” or “us” or “we” with this sort of stuff, I do not mean the United States (or, if I do, it’s in only an immediate, translucent way), and I do not mean some obvious particular parties—I mean, in a foggy way, everyone, individually and severally. Even whether or not they are currently playing.
(I think more countries should be. Like this one, which is well-educated and developed and with wonderful natural resources—admittedly saddled at the moment by an orc-headed paragon who thinks the pride of the nation is in pretending that’s it’s broke… but mostly one with a massive humility problem—which should really be able to do things for its own reasons—like, for example, as this fellow further explains in comments, get satellite “soil moisture data across Australia every three days—you would never get that from any satellite built by another country for its own needs. If we want that capability, we need to do it ourselves. And who is deciding whether we need the capability? . . . [O]ne way we say the satellite can pay for itself is if it were able to increase the efficiency of non-irrigated agriculture by 0.3%—a goal which I don’t think is ambitious. Apparently, providing soil moisture data to farmers in a timely way adds $16/hectare to their productivity.”)
An unplanned and late and possibly cheeky digression-revision, but just to underline: “We” in this is not a Cape Canaveral-centric conception. It’s Earth, and anyone even remotely biological in its neighborhood.
I went looking for gaps in the picture of the deuterium/helium-3 fusion economy. (Why? Because it’s my job—under “voting”—that sort of thing. And as a balm for a tired mind. Every now and then it strikes me how bizarre such a sentence might look, from a layperson, written apparently seriously . . .)
I thought I had found one gap; I wasn’t sure that anyone had actually checked how much helium-3 was in the gas giants, or that they could have, so I thought I would be admitting that that bit of the picture was all informed supposition.
But I found that the Galileo probe had sampled Jupiter’s atmosphere and found a 1 in 10,000 ratio of He-3 to He-4. (About the same ratio that the solar wind has driven into the Moon’s regolith for eons.) Since the ratio in Jupiter is imagined to come from the primordial nebula that birthed the solar system, the ratio should be the same for Saturn, Uranus, and Neptune. So something is known there.
But the real question, recoverable reserves, is beyond me for the moment. In fact, the questions expose a monkeyish level of comprehension in me. Like, Saturn’s atmosphere is about 7% helium to sift. (Saturn as a whole is supposed to be almost a quarter helium by mass, so the helium must be sinking. Uranus’ atmosphere is, plus or minus 3%, 15% helium, while Neptune’s is 19%.) I don’t know the total mass of Saturn’s atmosphere, as opposed to the planet’s mass; with that I could start to get somewhere. And I don’t know about how the floating sifting facilities would work or what they would do.
(I also am not sure how they’d float or if this would be a problem. Because we like to talk about surfaces, but we can’t see Saturn’s, we’ve decided that Saturn’s “surface” is the point where the atmospheric pressure is one bar—Earth’s sea-level pressure—although there’s a solid core down below somewhere. Also, Saturn’s gravity is only 107% of Earth’s, which is nice. So we could put a facility in conditions that are in at least those respects Earthlike, which reduces the scope for nasty surprises with designs that were worked out on Earth. But a dirigible sifter would need to be floating in an atmosphere of very cold hydrogen; a hot gasbag, then. Is that a problem? Would you need to park down in the denser atmosphere—which is better for sifting, but then would you have more trouble getting back up and out with the eventual full load? How heavy do sifters need to be? How big will the bag be? And… in what way do you come down out of space with a rocket drive and end up stationary in the atmosphere hanging under a big gasbag? Sounds tricky. Also, I don’t know how frequent charged H+ ions are in that almost-all-hydrogen one-bar-pressure atmosphere, but corrosion might be trouble. I’ve also seen the suggestion that there’d be no gasbag and the sifter would just hover on howling fusion-driven turbines, like jet engines stood on end. The turbines could also help to get the filled sifter to maximum altitude to where a rocket drive could take over.)
The same question for the Moon is much easier—but much uglier. I’ve seen an estimate of 1 to 2 million tonnes of helium-3 in its surface soil. So you could say that there’s a lot of helium-3 on the Moon. The estimate went on to say that, if 10% of it were recoverable, that 10% might power all of civilization at present levels (assuming it was doing it alone, without other sources or other helpful changes, which I think we can do better than) for 500 to 1,000 years. That’s easy to say.
But you could also say that there’s almost no helium-3 on the Moon, in that the concentration in the regolith is from one point four to fifteen parts PER BILLION. So to get one tonne of helium-3 you’d have to mechanically process from 150 MILLION to 714 MILLION TONNES of lunar rubble! Or more, less losses in the process. You’d have to do it with huge amounts of heavy machinery—all of which, unless we’ve gotten good at mining asteroids and startlingly good at manufacturing in space, has had to be hauled up out of Earth’s gravity well, the biggest expense in the game. And, with those machines, you have to do it on the Moon, in vacuum, with fourteen-day nights and massive temperature swings, and that glassy gritty razored dust that gets into every airseal and delicate instrument. The Moon is why some people call Mars friendly. (And to top it off, romantics will be complaining that the Moon is slowly losing its good looks.)
Granted, if you’re doing this at all you have advantages—if you’re to the point where you need helium-3 for fusion, you already have well-developed fusion power to help you. And it would be worth doing.
But you can see why, in thinking about this, I really neglect the Moon. I tend to think of mainly skipping past the Moon (though that doesn’t have to be realistic). The Moon is three short days away, while the gas giants are a long voyage, and their atmospheres are really cold, and the Uranus techs have to wear virtual-reality goggles to stay sane because there is less than no goddamn view . . . but the gas giants actually have a lot of helium.
And I love the time scale that the gas giants provide. Lunar-sourced fusion is great, but after a few thousand years you’re hungry again.
The question about recoverable reserves was really a way in which I tried to get a handle on things that kept me away from that word “inexhaustible.” It’ll always be a magnet for us, anything that smells like it—but for my sense of proportion I check my seatbelt when I hear the word “inexhaustible.” Nothing is inexhaustible, especially if we think it is. Better to keep the assumption that we’ll always need to figure something else out. But—if we have gotten to where we’re burning D and He-3—we should have the time to do so.
I also went looking for information on the nuclear-powered drives, that would, it’s to be hoped, be fusion-powered later on.
With nuclear-thermal rockets, the propellant, usually just liquid hydrogen, is heated to a very high temperature and then released. (That exhaust is non-radioactive, I should say; it’s just heated propellant, with the reactor all closed up.) The gross mass of this kind of spacecraft design is less than a chemical-rocket design, so, if you use it for the third stage in a rocket, the third stage can be built larger at the same weight and so can double the cargo a launch can get to orbit. This is the niche that one NERVA version was under consideration to fill. They tend to have lower thrust-to-weight ratios than chemical rockets (which push hard—while they last; the NERVA designs reached 7-to-1, but chemical rockets are 70-to-1), and the hydrogen requires bigger tanks to hold it in, so, if we had to restrict ourselves to the ones that actually got tested, we’d say that they don’t look like good engines to use for full launch from Earth (unfortunately), but in space they would be wonderful.
Although the Earth-launch role may not be out of the question. One later design, called Timberwind, that was cancelled when the Clinton Administration came in in the ‘90s (hey, I’ve just realized I remember that), was intended to reach a thrust-to-weight ratio of 30-to-1.
Now, thrust-to-(Earth)-weight is only a practical “working against gravity” measure (competing accelerations; at or below 1:1, the rocket does not move).
( . . . I just drove myself crazy looking up specific impulse yet again, which I always need to do; there are some squidgy things I always need to sort out.) (Specific impulse, abbreviated Isp, is a more general measure, more generally important for space drives. It’s measured in seconds (almost always it is; it’s measured in seconds when the fuel is given in units of mass or weight, that is; don’t get me started), and it represents how fuel-efficient a rocket is, or more precisely how fast a rocket can end up going (how much total velocity change it can make) if it uses X amount of fuel. Some drive designs with a high Isp have low actual accelerations; they just do it for a long time. Ion drives have very, very low thrusts and very high Isps, between 3,000 and 12,000 seconds. Chemical rockets have low Isps because, though they can subject you to multiple Gs, they don’t do it for long.
All of which is to set up for a capability comparison:
A liquid hydrogen/liquid oxygen chemical-fueled rocket, which gets the very best chemical result, has an Isp of 455 seconds.
Solid-core nuclear-thermal rockets, including NERVA, usually get a Isp of 850-1000 seconds, about double.
(Timberwind, the design mentioned above with the high thrust, was also expected to get about 1000 seconds.)
There are other kinds of designs, liquid-core and gas-core, but none of those have been built; some of those would be expected to get 1500 to 2000 seconds. (There’s an “open cycle” gas-core design that, if it could be really be built and work right, might get 3000-5000 seconds… but with the curious feature that it actually would have a radioactive exhaust plume. For use only far from Earth and in designated lanes—and we need not worry about it at the moment.) And if suitable fusion reactors become available, it’s a whole new question. There’s a lot I still don’t know.
Meanwhile that thrust-to-weight ratio is also relevant, because—well, in addition to the question of launching from Earth (with that nasty rocket-plume-pollution question gone)—we would need drives capable of lifting full helium-3 (and probably deuterium, lest I forget) loads up and out and into orbit around the gas giants, which (except for Jupiter) all have gravities around Earth’s. (Having replenished their hydrogen propellant right from the atmospheres, one would think.)
Which is where we came in.
Now, there is a book I need to obtain (probably by interlibrary loan; old copies are over a hundred bucks) about the history of the NERVA program, To the End of the Solar System: The Story of the Nuclear Rocket, by James A. Dewar. To help me with all this, of course, but one of the reasons is a little unusual.
James Dewar sounds like one cool cat, by the way. These days he’s head of the Pardee Center for Longer Range Global Policy and the Future Human Condition, which the RAND Corporation started with the purpose “to improve our ability to think about the longer-range future—from 35 to as far as 200 years ahead.” (!!)
I see where he did a presentation for the Long Now Foundation, the organization that Stewart Brand of Whole Earth Catalog fame started up to foster longer time horizons in society (it’s the one that added a digit to the way it writes years as a perspective-broadening exercise, so, this would be the year 02014). His presentation was on Long Term Policy Analysis, and involved a technique his group had developed to use exploratory-modeling software to help develop and test policies in the face of deep uncertainty by running thousands of scenarios of the future.
. . . I only vaguely understand what that means, but it sounds like just the thing somehow. :-)
(-laughing- [Appreciative swearword of your choice] I found a full monograph from them on Long Term Policy Analysis, in PDF. Here, you can take a look. This is a whole ‘nother deal from anything I talk about in here. I recommend clicking on it and saving the PDF now before moving on so you can bother yourself with it later. It’s the sort of thing where I ended up skimming faster and faster but with a bigger and bigger smile on my face and ending up thinking, “Man, I am totally befuddled but I want to see this in ACTION! This could be IT!”—while it’s written and fonted and arranged and printed in the utterly, crushingly, resistance-is-useless superprofessional style of a think-tank center spawned by the RAND Corporation.)
But I’ve gotten off track…
For much of my purpose I should probably actually get Dewar’s other book on NERVA, The Nuclear Rocket: Making Our Planet Green, Peaceful and Prosperous, because I can find cheaper copies. Now, I got a big grin when I found it on Amazon—because he realized too late that he had left something out of the book, and, it being too late to make the change, he did what he could to remedy this by writing just in the Amazon review section on the page for it. I love the straightforward problem-solving of this, however last-ditch . . . and his note happens to address an important concern I wanted to research about nuclear drives:
"Mea culpa! I must apologize to those who buy 'The Nuclear Rocket.' In writing it, I had a senior moment and completely forgot a crucial point in my argument that a cocoon (or wrapper, enclosure or whatever you call it) can be developed to contain a nuclear rocket engine and its radioactive materials during its launch to and return from LEO. I speak of the Titan II accident in Arkansas in 1980. I knew about it, as I was in the nuclear weapons program at the time, but I simply didn't remember it until about a month ago when I sat bolt upright in bed at 2:00 am.
"Let me summarize what I should have included.
"The Mark-6 was the reentry vehicle (RV) for the W-53, a 9.2MT warhead, and it sat atop a Titan II ICBM. In September 1980, while performing maintenance, a worker dropped a wrench socket that fell 70-feet and punched a hole in a fuel tank. Efforts to prevent the accident proved futile and the Titan II blew up in its launch silo. An extraordinarily violent explosion, it blasted a 740-ton launch pad door 200-feet in the air and it landed 600-feet from the silo. The Mark-6 followed the 740-ton door skyward, ricocheted off it and bounced along the ground before coming to rest several hundred feet from the silo.
"One Air Force crewman died of injuries incurred and another suffered a broken leg after being blown 150-feet from the silo. Though unclassified photos do not exist, the Mark-6 reportedly remained intact and contained the W-53, which obviously did not explode. You would know if a 9.2MT bomb goes off. Its high explosives also did not detonate; this would have shredded the RV. So no radioactive materials were dispersed to the environment; in other words, the plutonium and uranium remained either in the weapon casing itself or within the RV.
"This summary was obtained from unclassified sources. Classified reports on the accident exist, but those involving the Mark-6 and W-53 will probably remain classified. Still, I have no reason to doubt the unclassified reports: neither the W-53 nor its high explosives detonated and no radioactive materials were dispersed to the environment. The latter would have involved special cleanup crews that would have been quite visible to the general public and therefore impossible to keep secret.
"If the Mark-6 can withstand such an extraordinarily violent explosion and not release any radioactive materials—it clearly was not designed to be blasted out of a silo—I firmly hold we have the know-how and expertise to build a cocoon (wrapper, enclosure or whatever you call it) that can withstand all accident scenarios of using a nuclear rocket engine to reach and return from LEO and not release any radioactive materials. If I am right, and I think I am, then we drop our launch costs dramatically, perhaps to $100/pound and then even lower. In summary, I strongly believe it's time to stop doubting and lambasting our technological muscle and get our country moving into Space, taking the world with us. But you have to read this book for that part of the argument."
I don’t know how any author ever dares decide his book is finished. :-) But, yes, the matter of devising good containment of radioactive material when launching in case of mishaps was something I’d been thinking about. It does seem to me that really solid designs are possible and should do it, although I do need to look into it further. (I have only just now remembered one person, somewhere way back, who objected to an idea like this by rhetorically asking how they could possibly be sure of keeping containment in the teeth of “the incomprehensible force” of a rocket explosion? He meant it as a truthful superlative for the event, but for my part I took it that the forces involved are comprehensible, and calculable.)
I still want to get To the End of the Solar System, though—because of the history of the NERVA program that it includes. Maybe his other book includes it too, but To the End of the Solar System evidently has a lot about how such a program is maintained and shepherded along and kept going, institutionally… and also I first found out about the book because it was the background citation for a particular passage in the Wikipedia entry about NERVA that I was absolutely stopped cold by. I have said that the NERVA models ground-tested just fine, that the program was cancelled not for “failure” but for other reasons . . . political, budget, NASA’s different priorities, etc. But this passage puts that cloudy summary into a very specific shape:
Members of Congress in both political parties judged that a manned mission to Mars would be a tacit commitment for the United States to decades more of the expensive Space Race. Manned Mars missions were enabled by nuclear rockets; therefore, if NERVA could be discontinued the Space Race might wind down and the budget would be saved.
I have never heard this, at all. If accurate, it puts a whole new light on things. I have been interested in how the Big NASA of the space race was wound down (and how its subsequent degradation was begun), i.e, Nixon deciding that NASA would no longer have a privileged place in the budget and that space would now be one priority competing with other priorities (my reaction was: Wait, before you could have it NOT having to compete with other priorities? You can do that???) . . . but this is different.
As far as I am aware, the American public was only ever told that it would be a while before we went on to Mars. They were never told that any decisions were being made not to go—certainly not any decisions about not going later. When NERVA was cancelled in 1972, the NASA budget was already down from a peak of 4.4% in 1966 to 1.5% of the budget as a whole; Apollo ended that year. (One could argue that future space budget surges would be lower than Apollo’s, because so much development had already been done, but I don’t know that and it doesn’t matter.) This sounds as if the prospect of future budget surges was quietly cut off—by cutting off the thing that they thought was required—prophylactically . . . while publicly it was just said that Mars was down the road a ways, and wouldn’t happen immediately—and the people who were thinking this way just hoped (accurately) that the public would just go to sleep.
Fascinating. I have to check it out.
And infuriating—because I have had in mind reasons for a well-developed space program and space infrastructure… reasons why we could stand to have one already in place now . . . and reasons for the sort of drive capabilities that nuclear drives would make possible, that have nothing to do with just an intrinsic value of flags and human footprints in the sands of Mars, or on the Moon for that matter.
I have rarely explained it well. But, for this series of posts, at least, it will be clear that it’s been a very long time since I have thought of spaceships and ecological matters as being in separate baskets at all.
And I think this post is long enough. The euphoria of Telling History What To Do will pass, will pass. But I’ve worked myself up a fair buffer.
Last updated July 09, 2015