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The Tragic Tale of Saddam Hussein's “Supergun”
- Pxtl 11y agoWith all the talk of Musk's Hyperloop, now I'm curious if the barrel was evacuated (if that's worth it). Even though this wouldn't be appropriate for use for delicate satellites, I wonder if this would be a critical piece of equipment for industrialized space - raw materials like fuel and oxygen and structural materials. Unfortunately full satellites would be a challenge since googling reveals that experiments involving these things included 10,000 gees of acceleration.
- comicjk 11y agoEvacuating the barrel wouldn't do much. It's nice to skip 150m of air resistance, but when you emerge from the barrel, you still have 15 km to go.
- nickff 11y agoThe main problem with having an air-filled barrel is that when the projectile is going faster than the speed of sound, it is compressing all the air in front it, all the way to the end of the barrel. Once the air can no longer get out of the way, it is along for the ride (until outside the confined spaces of the barrel). Carrying 100m worth of air will heat up the barrel and projectile (as the air is being compressed), as well as adding a great deal of friction.
- talmand 11y agoI would be curious about any potential differences between the two once the projectile leaves the barrel. Would all that super-heated air being shoved out ahead of the projectile make a difference in the shock of it leaving the barrel?
- nickff 11y agoThere would be an incredibly loud sonic boom when the projectile left the unevacuated barrel, but since the projectile is going faster than the speed of sound, it would not benefit from the pressure wave; in fact, it would probably slow down, and possibly be destabilized when it penetrated the thick layer of (possibly plasma-phase) air. It is also likely that when the pressure wave left the barrel, the entire barrel would shake itself to pieces (unless it had some way of damping the axial waves going back and forth through the barrel, akin to a 'water-hammer' effect).
- arprocter 11y agoI'm not sure how/if it scales, but here's an article about different lengths of 5.56mm barrels, with graphs of pressure and velocity: http://www.sadefensejournal.com/wp/?p=1093 http://www.sadefensejournal.com/wp/?p=1093 In reference to the second graph on the page, mach 1 is apparently 1125.33 fps Do we know if the space guns are rifled or smooth bore?
- nickff 11y agoSmooth bore as far as I know. Even tank cannons are mostly smooth-bore these days. The problem with those graphs is that they are not optimizing propellant quantity for each barrel length. Adding an axis for quantity of propellant shows that you get diminishing returns to increasing barrel length and propellant, but there is a limit to how much you can increase both without increasing the barrel's thickness (as well as the firing mechanism's strength). You also have to remember that a gun will require > Mach 25 to get to orbit, and air acts differently at that kind of speed (, and once past ~Mach 3).
- arprocter 11y agoThanks for the insight - I guess it doesn't scale! Is there a reason the space gun would be at a 45 degree angle and not pointed vertically? I know the reason rocket launches happen as close to the equator as possible, but they still go straight upwards...
- nickff 11y agoRockets only go up for a little while; most of the propellant is used to build up speed in the 'horizontal direction'. There have been some arguments that a strictly vertically-firing rocket would be best for going outside of Earth orbit, but the current strategy for all launches is to go up until outside the thickest part of the atmosphere, then go horizontal, to build up to orbital velocity.
- arprocter 11y agoAfter reading about the end of of Project HARP - it seems like they intended to use the gun to fire a rocket, and after a certain altitude the engine would ignite to get into space.
- ajuc 11y agoWould shooting a powerful laser to heat the air in the path before launch help?
- devenson 11y agoOr perhaps a small rocket.
- jasonwatkinspdx 11y agoThat 150m of air is constrained into a column by the barrel. It is a big deal and light gas guns commonly evacuate the barrel.
- trhway 11y agoevacuating barrel will help reach the speed. Evacuation is very easy to do, yet helps tremendously. The gun can be built somewhere in the Andes, at 4 km altitude. It can be pretty long there. Plus using either ablative head - like new Russian-Indian air missiles - or small forward jets - similar to Russian 200miles/h torpedo - will help to decrease atmospheric speed losses. The 6.5 Mach gets you to 180km altitude from powerful regular gun - https://en.wikipedia.org/wiki/Project_HARP https://en.wikipedia.org/wiki/Project_HARP : "On November 18, 1966 the Yuma gun fired a 400 lb (180 kg) Martlet 2 projectile at 7,000 ft/s (2,100 m/s)[1] sending it briefly into space and setting an altitude record of 180 km (590,000 ft; 110 mi);" That means that it was going at least 5 Mach after reaching 30km altitude. Doesn't looks like such a big loss of speed in the atmosphere - only about 1 Mach due to atmosphere as the other 0.5 Mach - due to gravitation.
- jdeibele 11y agoFrederick Forsyth's "The Fist of God" is a good read and uses Gerald Bull and his super gun as part of the plot.
- VikingCoder 11y agoShows up in Michael Flynn's "Firestar" series, as well. "The Boomer" is what they call it, I think. It was in the side of a mountain in South America, and it was filled with gas.
- theklub 11y agoThis reminds me of the huge pumpkin guns people make. https://www.punkinchunkin.com/registered-machines.html https://www.punkinchunkin.com/registered-machines.html
- pascalmemories 11y agoOddly, the article fails to mention the UK government attempt to railroad into prison the directors of the UK company asked to make the pipe components, by covering up the fact they had approved the export using 'public interest immunity' certificates to hide evidence from the courts. https://en.wikipedia.org/wiki/Arms-to-Iraq https://en.wikipedia.org/wiki/Arms-to-Iraq
- tonmoy 11y agoBBC is really a great source of unbiased new when UK is not involved in the story.
- beeboop 11y agoThat's like saying RT.com is unbiased when it doesn't involve Russia, which is very much not the case.
- sydneysider 11y agoI'd disagree, along with Al Jazeera, RT is one of my staple news sources.
- stephenboyd 11y agoAll news media has bias. RT's bias is good for covering some of the topics and perspectives neglected by typical Western news sources.
- zaroth 11y agoI love the twist of submerging almost the entire barrel in the ocean, pretty awesome to wrap your brain around how that could actually work out. It was also really interesting to hear Hunter's thoughts that even if the physics all works and launch costs could be cut 1/10th, how it would still be unworkable for someone SpaceX to invest in the R&D alongside their reusable rockets.
- maxander 11y agoIt would be interesting to see a quantitative head-to-head comparison, but my guess would be that once you have the technology to retrieve first-stage rocket engines after launch space-guns aren't economical- the fuel used lifting the engine itself may be expensive, but the energy losses from hitting sea-level atmosphere at ~8km/h would have to be astronomical. ...As it were.
- gvb 11y agoSpaceX appears to be competitive even without reusing the first stage: At its 2013 launch price and at full LEO payload capacity, the Falcon 9 v1.1 cost $1,864 per pound ($4,109/kg). Ref: https://en.wikipedia.org/wiki/Falcon_9#Launch_prices https://en.wikipedia.org/wiki/Falcon_9#Launch_prices From TFA: The cost was roughly $1,727 per kilogram, adjusting for inflation. By comparison, Nasa estimates that it costs $22,000 per kilogram to launch a modern satellite into orbit using conventional rockets.
- mrfusion 11y agoI disagree. With a rocket you have to lift all your fuel. With a space gun the fuel stays on earth and only the payload goes to space. Look up the rocket equation to see what a huge difference this makes.
- maxander 11y agoDoes it, though? I mean, I've played KSP, I know the rocket equation. But with a space gun, your vehicle only winds up moving as fast as the propellant pushing it out- so that mass of fuel (more explosive than fuel, I guess) still has to be accelerated to near-orbital speeds in order for the gun to work.
- at-fates-hands 11y agoI love the tone of the article. It struggles to assert that although the gun could be used as a weapon, it had more potential as something to launch a satellite. You would have to be pretty naive to think the Iraqi's, who always wanted to be the dominant Persian Gulf state in the region, would actually use this for its intended purpose and not weaponize it to intimidate its neighbors in the region.
- maxander 11y agoGuns, unlike satellite launchers, need to be aimed at enemies in order to be useful- something hard to do if its built into a hill. I mean, of course the Iraqi military (like everyone else) thought about it as a weapon first, but if I were Bull I'd have been happy to con them out of spending the same money on more effective weapons.
- stcredzero 11y agoSaddam Hussein was a big Sci-fi fan. I'd guess he knew it was supposed to be a launcher first, and still went for it.
- trhway 11y agoit is also helps to be a dictator when it comes to big projects - no need to convince/pitch to investors and various levels of government and elected reps, public opinion, obtaining permits, etc... :) You just do it.
- stcredzero 11y agoWhen he first started to talk to Gerald Bull, he was Defence Minister or something like that.
- effie 11y ago> Saddam Hussein was a big Sci-fi fan. That sounds so weird. Could you post a reference?
- brandonmenc 11y agoThere was a great HBO movie from 1994 called "Doomsday Gun" about this. http://www.imdb.com/title/tt0109650 http://www.imdb.com/title/tt0109650
- teh_klev 11y agoI agree, I watched that a couple of years ago and very much enjoyed it.
- nkurz 11y agoA powder gun like the one used in Harp and a gas gun like Sharp both work in the same basic way – expanding gases. The lighter the gases molecular weight, the faster it expands in air. Gunpowder has a molecular weight of 22, slightly less than air at around 28, but ignited gunpowder is incredibly hot, so that’s why it expands so quickly. The hydrogen used in gas guns, however, has a molecular weight of two so expands extraordinarily quickly in air. I couldn't understand from the article how the hydrogen was being used in a "gas gun". Since pure hydrogen doesn't ignite, wouldn't we care about the molecular weight of the oxidizer as well? It turns out the "light gas" is important just for it's low molecular molecular weight. It's never ignited, and one could substitute Helium for Hydrogen if one wanted. The gas is a second stage in addition to, rather than instead of the gunpowder. It's like a spring-air gun, but instead of spring you use an explosive charge. Here's Wikipedia: https://en.wikipedia.org/wiki/Light-gas_gun https://en.wikipedia.org/wiki/Light-gas_gun And here's some PVC experimentation: http://www.chrisfenton.com/2-stage-light-gas-gun/ http://www.chrisfenton.com/2-stage-light-gas-gun/
- B1FF_PSUVM 11y agoSomeone needs to pillage Jules Verne's books for movies, so that news writers know about them ... There's at least two super-guns in them, both launching to space as described (one of them "and beyond", it's a Moon shot). https://en.wikipedia.org/wiki/The_Begum%27s_Fortune https://en.wikipedia.org/wiki/The_Begum%27s_Fortune https://en.wikipedia.org/wiki/From_the_Earth_to_the_Moon https://en.wikipedia.org/wiki/From_the_Earth_to_the_Moon
- rdl 11y agoUniversity of Washington's Ram Accelerator (RAMAC) (https://en.wikipedia.org/wiki/Ram_accelerator https://en.wikipedia.org/wiki/Ram_accelerator) is what I think will ultimately win. It's basically a long tube with mixtures of natural gas, designed to work like a ramjet.