Category: Bombs and rockets

Military matters and state security: the hard-edged kind of international relations

Bright or invisible rocket exhaust

LOX and RP-1 never burn absolutely clean, and there is always a bit of free carbon in the exhaust, which produces a luminous flame. So when you’re looking at TV and see a liftoff from Cape Kennedy—or from Baikonur for that matter—and the exhaust flame is very bright, you can be sure the propellants are Lox and RP-1 or the equivalent. If the flame is nearly invisible, and you can see the shock diamonds in the exhaust, you’re probably watching a Titan II booster burning N2O4 and 50–50.

Clark, John D. Ignition! An Informal History of Liquid Rocket Propellants. Rutgers University Press Classics, 2017. p. 96

One-way rocketry

Finally somebody in authority sat down and thought the problem through. The specifications of JP-4 [jet fuel] were as sloppy as they were to insure a large supply of the stuff under all circumstances. But Jupiter and Thor [ballistic missiles] were designed and intended to carry nuclear warheads, and it dawned upon the thinker that you don’t need a large and continuing supply of fuel for an arsenal of such missiles. Each missile is fired, if at all, just once, and after a few dozen of them have been lobbed by the contending parties, the problem of fuel for later salvoes becomes academic, because everybody interested is dead. So the only consideration is that the missile works right the first time—and you can make your fuel specifications just as tight as you like. Your first load of fuel is the only one you’ll ever need.

Clark, John D. Ignition! An Informal History of Liquid Rocket Propellants. Rutgers University Press Classics, 2017. p. 95–6

Pre-computer rocket propellant chemistry calculations

[Calculating rocket fuel performance mathematically] gets worse exponentially as the number of different elements and the number of possible species [of reaction products] increases. With a system containing carbon, hydrogen, oxygen, and nitrogen, you may have to consider fifteen species or more. And if you toss in boron, say, or aluminum, and perhaps a little chlorine and fluorine—the mind boggles.

But you’re stuck with it (remember, I didn’t ask you to do this!) and proceed—or did in the unhappy days before computers. First, you make a guess at the chamber temperature. (Experience helps a lot here!) You then look up the relevant equilibrium constants for your chosen temperature. Devoted and masochistic savants have spent years in determining and compiling these. Your equations are now before you, waiting to be solved. It is rarely possible to do this directly. So you guess at the partial pressures of what you think will be the major constituents of the mixture (again, experience is a great help) and calculate the others from them. You add them all up, and see if they agree with your predetermined chamber pressure. They don’t, of course, so you go back and readjust your first guess, and try again. And again. And eventually all your species are in equilibrium and you have the right ratio of hydrogen to oxygen and so on, and they add up to the right chamber pressure.

Next, you calculate the amount of heat which would have been evolved in the formation of these species from your propellants, and compare that figure with the heat that would be needed to warm the combustion products up to your chosen chamber temperature. (The same devoted savants have included the necessary heats of formation and heat capacities in their compilations.) And, of course, the two figures disagree, so you’re back to square one to guess another chamber temperature. And so on.

Clark, John D. Ignition! An Informal History of Liquid Rocket Propellants. Rutgers University Press Classics, 2017. p. 84 (italics in original)

What it’s like to hear but not see the Toronto Air Show

A tweet of mine, written in a moment of irritability aggravated by the sound of jets roaring overhead, has gotten some attention by virtue of being incorporated into some news articles about social media commentary on the Toronto Air Show.

In addition to my standard gripes about the wastefulness of jet engine use, the undesirability of unwanted background noise, and the militarism embodied in combat aircraft development, I suggested that there are people in Toronto who find the experience of being a bystander during the noise as troubling or a reminder of trauma, having heard military jets operating at close quarters during any number of recent conflicts, from Gaza to Afghanistan to Yemen, or during interception flights carried out by domestic air forces.

A disturbing amount of the response on Twitter expressed anti-immigrant sentiment, particularly an assertion that (a) people who have experienced conflict and now live in Toronto now live in preferable life circumstances and therefore (b) they owe certain moral obligations to people who previously lived in the place they now inhabit, to wit just lumping it and not complaining while these acrobatic displays are put on. To some extent my interpretation of the comments was inevitably coloured by Twitter’s reputation as an especially hostile and personal platform, but I think even when viewed with as much objectivity as can be mustered they brought unnecessary hostility to a discussion ultimately about public policy, specifically whether such spectacles should continue.

It’s entirely fair to criticize me for assuming what somebody else’s life experience would mean, in terms of their experience of these noises. That being said, the basic parameters of something like post-traumatic stress disorder are publicly known and it seems plausible to me that anyone who has traumatic memories of being close to combat in which jets operated (whether as a soldier or a civilian) would have some chance of being triggered by the sound of an air show. Given the population of Toronto, it’s plausible that hundreds of people with PTSD are within earshot of each loud noise made by flying aircraft. It’s much more speculative, but I have also wondered about the number of people who can have panic attracts triggered by a stimulus like a jet engine sound find it triggering due to associations they have made through fiction, specifically quasi-realistic military computer games and films which realistically depict violence like Saving Private Ryan. Statistically very few people, even during times of mass conscription, faced intense combat of the kind depicted in the film, but probably a majority of the adult population has now seen multiple detailed immersive representations, whether through films like Spielberg’s or depictions like HBO’s Generation Kill or Band of Brothers.

I don’t want to suggest that it’s the same thing at all, but I have my own negative associations with hearing but not seeing military jets at low altitude nearby, as I lived in North Oxford within earshot of at least some of the approaches to RAF Brize Norton and we used to listen to Vickers refuelling aircraft and B-52s flying in at all times of day and night (familiar eventually in their shrieks and rumbles) and speculate about whether they were coming back from Iraq or from Afghanistan, maybe carrying coffins.

I don’t think social media griping is going to lead to the abolition of the airshow, but I do think it’s a good thing to have a public dialog about what people in the city are going through in terms of their mental health and the choices we make together affecting it.

Those with any opinions on the matter are invited to comment, anonymously if you like.

Attractions of monopropellants

A monopropellant is a liquid which contains in itself both the fuel and the oxidizer, either as a single molecule such as methyl nitrate, CH3NO3, in which the oxygens can burn the carbon and the hydrogens, or as a mixture of a fuel and an oxidizer, such as a solution of benzene in N2O4. On paper, the idea looks attractive. You have only one fluid to inject into the chamber, which simplifies your plumbing, your mixture ratio is built in and stays where you want it, you don’t have to worry about building an injector which will mix the fuel and oxidizer properly, and things are simpler all around. But! Any intimate mixture of a fuel and an oxidizer is a potential explosive, and a molecule with one reducing (fuel) end and one oxidizing end, separated by a pair of firmly crossed fingers, is an invitation to disaster.

Clark, John D. Ignition! An Informal History of Liquid Rocket Propellants. Rutgers University Press Classics, 2017. p. 7 (italics in original)

What if someone breaks the nuclear weapon taboo?

Many problems in nuclear strategy are unpleasant or even horrifying to contemplate. As the number of nuclear-armed nations grows, the chances that one will be put in a desperate situation and choose to use one more more nuclear weapons likely rises.

An article by Vince Manzo and John Warden considers potential American responses to the use of a nuclear weapon by a hostile power, including four scenarios involving North Korea and Russia.

Among all the international norms under threat, the norm of non-use of nuclear weapons is among the most valuable. If at all possible, it should be reinforced even if one state does use nuclear weapons. As the article illustrates, however, that will be one among many strategic considerations, and no option offers the kind of certainty that would be desirable.

Open thread: ballistic missile defence

An episode involving missile defence* from the West Wing holds up very well today. The craggy old American chief of staff is in favour, out of fear of what rogue regimes might do to America. The British ambassador is opposed because it’s impractical, violates international law, and risks worsening the global nuclear weapons situation.

I can see why people like the idea of being able to stop a few missiles launched by North Korea or Iran, or by a rogue commander somewhere. At the same time, I think the dangers of a nuclear arms race make the development and deployment of such a system unwise, even if the major technological hurdles could be overcome. It’s the classic security dilemma: you build something meant to make you safer, potential opponents interpret it as making them less safe (by reducing the credibility of their deterrent) so they build expensive countermeasures. In the end, everyone has wasted money on the race and everyone ends up less safe. It could also tempt decision-makers into recklessness, based on false confidence that the system will nullify any response to their aggression.

We should be working to de-alert and dismantle the nuclear arsenals of the authorized nuclear powers under the Non-Proliferation Treaty. Against that backdrop, resisting proliferation to new nuclear states would be more plausible.

* I don’t mean defending things like aircraft carriers from ballistic missiles. I mean systems to protect domestically-located military facilities and population centres from ballistic missile attack, probably with nuclear weapons.

Ellsberg’s broad conclusion

Yet what seems to be beyond question is that any social system (not only ours) that has created and maintained a Doomsday Machine and has put the trigger to it, including first use of nuclear weapons, in the hands of one human being – anyone, not just this one man, still worse in the hands of an unknown number of persons – is in core aspects mad. Ours is such a system. We are in the grip of institutionalized madness.

Ellsberg, Daniel. The Doomsday Machine: Confessions of a Nuclear War Planner. Bloomsbury; New York. 2017. p. 332 (italics in original)