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Neal Stephenson On Rockets and Innovation
Dr. Gamera writes "Science-fiction author Neal Stephenson gives us his perspective on the history of the development of rocketry. He uses that history to illustrate the phenomena of path dependence and lock-in."
It's a neat article, as usual with Neal, but the ending is odd. He says the current state of rocketry is at a local maximum, it's not going to get appreciably better, and there may be other ways of putting stuff in orbit that are better, and then he says he doesn't know why we aren't trying those other better things. This, after spending the previous twenty paragraphs writing about how the US has spent four trillion dollars to get to the top of this local maximum, and the old USSR spent about the same, and in the process we've established a huge military-industrial complex based on the money still flowing into that development path, with lots of political inertia greased by manufacturing and administrative money going into congressional districts... and he wonders why we're not considering spending another trillion dollars on a different, unproven system that would probably involve taking money from the people who are now getting it? He's already answered his own question, and that's surprising because he's a very bright person and does a good job of analyzing the subject.
Nostalgia's not what it used to be.
Stepheson makes this point late in the article:
"There is no shortage of proposals for radically innovative space launch schemes that, if they worked, would get us across the valley to other hilltops considerably higher than the one we are standing on now—high enough to bring the cost and risk of space launch down to the point where fundamentally new things could begin happening in outer space. But we are not making any serious effort as a society to cross those valleys. It is not clear why."
It's somewhat clearer why, to me.
I want to buy a more fuel-efficient car, and keep my current, less-efficient car. My current car is useful for many things, but commuting to work could be done by another, more efficient one. Here, however, is the rub. Despite the improvement in fuel economy, it is still a net increase in cost to me for a fairly long time. Acquisition, insurance, and upkeep consume most of the fuel savings. Yes, it would be better for he environment also, but that doesn't immediately or directly impact my costs very much. So I put off buying that car.
Our current methods of delivering object into space work well enough, and the alternatives are both unproven and not sufficiently advantageous to warrant immediate adoption.
However, as we re-enter manned space exploration, we will be looking for heavy-lift options that don't actually exist today, and those present the opportunity to develop new methods. Avoiding the vertical portion of a rocket launch also avoids the need for massive thrust to overcome gravity that directly. Stephenson alludes to this, and 'space planes' are the current focus, along with some multi-mode concepts. NASA'a failing Ares program is a fair example of lock-in that Stephenson is writing about. Being more open to the development of ultra-high-speed vehicles and their engines might offer both better alternatives and true advances. But that takes ingenuity and a willingness to risk that NASA doesn't seem to possess right now. Bad climate to propose trillion-dollar space programs, though we've been willing to propose trillion-dollar stimulus packages for more mundane projects, such as propping up failed financial institutions.
Imagine the impact of a trillion-dollar space plane project. Would US students consider a career in engineering if they saw both the opportunity to be part of a cool new future, and the employment options as well? Would this give US aerospace companies something else to sell instead of weapons systems, and is that a good thing? Would it spur international competition, and is that good? Would it divert China's resources into something besides crushing the world's manufacturing competitors? Does that matter? Would a trillion dollars given to this project do more good than giving it to the bankers? Will the bankers also flourish in the glow of this project?
deleting the extra space after periods so i can stay relevant, yeah.
Suppose you accept his premises that our current state of rocket technology evolved in part due to key improbable events. As a result, we've continued that technology, to "climb to the top of that hill" as he puts it. That doesn't, by itself, automatically mean there must be higher hills to climb. We may have purposefully or accidentally climbed the highest hill we are currently capable of climbing. Perhaps we would have been further along with some other technology if we hadn't climbed this hill, but it might not have been better overall. Right? I mean, it could have turned out like our quest for magnetically confined fusion.
Blind people develop superior hearing to sighted people. I'd still rather have my vision, and I don't think that's entirely due to path dependency.
Same mistake with the combustion engine. Yes, we are getting close to maxing out the technology. But it's not clear that, if we had not developed it in the first place, we would have come up with something more effective in its place. It's not even clear we would have come up with something *as* effective. It's not even clear we even have anything plausible *yet* that would be as effective.
The fundamental mistake in this article seems to be an assumption that the grass is greener in the counterfactual, but he presents no evidence to persuade us that this is actually true.
If you don't know where you are going, you will wind up somewhere else.
I like how one of the things Stephenson blames in his article for the rocket lock-in is, "engineering culture," that is resistant to change. I often find that nontechnical folk (and no, sci-fi writing does not count as a technical pursuit) use terms like, "engineering culture," or "scientific elitism," to describe phenomena brought about by actual technical details. In other words, that engineering culture doesn't develop simply because we engineers are resistant to change. It develops because we engineers crunch the numbers and have to deal with reality.
Anyone who thinks that engineers working in the space launch industry are resistant to change just for the shits is pretty misinformed. When it comes right down to it, we're the ones who would love to find a new Pandora's box technology that could get us into space faster, cheaper, and safer. Hell, we have devoted our lives to pursuing the development of the space industry. If anyone wants to see men and women living on Mars, manufacturing in orbit, and fucking onboard inter-galactic colony ships, it's us. Unfortunately, we don't have the luxury that sci-fi authors have of writing about some great new idea and just assuming it will work. We have to test material strengths. We have to plot thermal loads. We have to damp harmonic oscillations. We have to produce enough energy to overcome gravity. Those aren't trivial tasks. And we don't get to defy the laws of thermodynamics and gravity with some hand-wavy bullshit about, "couldn't this idea totally work in theory?!"
So yeah, there are lots of proposed theories and ideas on how to get to orbit. Great, congratulations Mr. Stephenson, you have an imagination. And, awesome, you can see sunnier hilltops across the valley that reach higher than the one we are standing on now. That's a great fantasy land. I hope you enjoy living in it. But while you draft up clever metaphors based on cherry-picked "facts" and unrealistic assumptions, those of us working in the industry, you know, the ones doing the math, actually have to look at the numbers. And those distant, high hilltops you see, well they might not be as high as you think. And all those, "innovations," on how to get to space, well they might not be as Earth-shatteringly ingenious as you think.
I'm not saying there's not room for improvement, there definitely is. But until someone shows me some numbers that prove a space-elevator, a launch loop, or a space fountain can be built, today, without unobtainium (in the form of some material, or some epic power source), I am going to delegate those ideas strictly to fantasy-land for now. And as for things like space planes, hypersonics, multi-propulsion-type vehicles, and so on, we are trying them, to an extent. And, believe it or not, just like rockets, they are still fucking difficult to get right. That's why it takes a long time to develop them. In the end, chucking something out of our gravity well is no easy task, no matter what method you take. And it is expensive, in both time and energy, no matter what technology you utilize. So stop lamenting about how poor off we are compared to where we could be. We're doing everything we can with what we've got. If that's not good enough for you, vote to give us more money or design a small, portable power-plant that can produce a proper metric fuckton of thrust.
In the end, engineering culture is just a term being used to say, "technical shit that I don't understand well enough so I'lll use it as a scapegoat to justify my preconceived notions"
Motorcycles, Robots, Space Gossip and More!
Yeah, I was really disappointed by this from Neil. It's extremely poorly done.
1) "Without the Nazis, rockets wouldn't have happened" -- the Nazis merely accelerated something that was already ongoing. All major nations were working on rocketry. There were two primary purposes: sounding rockets, and aircraft. This was, you'll recall, before we knew that jet engines would win out over rockets for airplane propulsion, and all sides were working on rocket-propelled craft. Even if rocket-plane propulsion were to stop, sounding rocket development would have continued to advance to V2-scale. WWII just accelerated things.
2) "A-bombs were too expensive and militarily ineffective" --really? Taking out an entire city and its mass production capability isn't worth the cost to purify some uranium? Perhaps if you divide the number of bombs dropped on Japan by how much we spent on the Manhattan project, maybe, but most of that was a sunk cost. The world was terrified of atomic bombings.
3) "Without A-bombs, rocket development would have ceased." -- ignoring the issues in #1, after WWII, rocketry had already captured the public mind. In fact, even during WWII, Von Braun had already been talking up, and getting military interest in, orbital space bombers that would stay in orbit and drop their (conventional) payloads on enemy targets at a moment's notice (plus taking spy photographs, etc, all without risk of being shot down) during WWII.
4) "All payloads are sized to be like A-bombs" -- not in the least. There's a huge range of payload profiles and lift capabilities of modern rockets. Just because the stacks were originally designed for a specific load doesn't mean that all of their descendants are.
Probably the most disappointing line, however, was:
5) "Rockets are as close to perfect as they're ever going to get." Oh really? Scramjets? Nuclear thermal? Strained-bond chemicals? Cryogenic solids and hybrids? The dramatic materials enhancements we're starting ti get (which has a profound effect on rocket performance)? Advanced heat shields? And on and on. Plus, just ignoring radical changes, look at how much of a difference design approaches have toward launch costs -- compare the Space Shuttle to SpaceX, for example. Rockets are nowhere close to being completely optimized.
There's a lot of legacy that could be criticized with the space industry, esp. the government space industry. Nobody would insist on keeping on reusing as many shuttle components as possible for a next-gen stack if it wasn't all the jobs on the line. Even the "radical", ground-up redesigns, such as SpaceX's Falcon, still uses some legacy parts. So there is a lot of legacy stuff to criticize. But Neal only skimmed over these things :P And he skipped the most important part of such an article: proposing alternatives. So you don't like rockets -- fine. Let's talk alternatives. What do you like -- skyhooks, space elevators, launch loops, ballistic launch, what?
I guess I just let my urge to spawn soldiers for Satan's dark army get the better of me.
Just another example, regarding the "globalization effect" he's talking about: Thorium based reactors that the US doesn't give a rat's ass about, but may well play a major part in solving the energy crysis and how China is thinking about building them.
The big problem with rockets is that the fuel has to travel with the vessel. I haven't done the math but I have heard roughly half of the fuel is spent accelerating the other half to the speed of sound. If you have a land-based system that accelerates the vessel to the speed of sound you can make the vessel half the size (or replace half the fuel with payload).
Speaking of the fuel, most of the weight comes from the oxidizer. With a hydrogen-oxygen rocket you need one oxygen atom for every two hydrogen. Oxygen has an atomic weight of 16 while hydrogen has an atomic weight of 1. So 89% (16/18) of the mass is oxygen.
Imagine if you had a railgun that accelerates a ram-jet past the speed of sound, the ram-jet burns oxygen from the air and accelerates to nearly orbital velocity, finally a rocket takes over to reach orbit. If we could get that working we would have much better access to space.
It is worth noting Burt Rutan uses a mother ship to launch his space craft. The mother ship gets up to speed by burning oxygen from the air in standard jet engines. The spacecraft then drops off and launches with a substantial head start.