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Minarchist posted:Didn't they try something like that with a nuke at the bottom of a shaft and record the oversized manhole plugging it being blasted off? Even with the fastest camera they had they got a single blurry frame of it being blasted into the air at god knows how fast before it was completely vaporized via friction with the atmosphere. http://savvyparanoia.com/the-fastest-man-made-object-ever-a-nuclear-powered-manhole-cover-true/ quote:As it happens, a very high speed film camera was recording the event and was expected to capture in slow motion the path and speed of any ejecta from the hole. Unfortunately, the camera, which had quite a wide view of top of the hole and and the area around and above, recorded the “manhole cover” on only one frame. There was no malfunction of the camera, it’s just that the “manhole cover” blasted out of sight so fast that the camera only saw it for one frame. Later calculations showed that the heretofore mundane four-foot metal disk had been launched at six times Earth’s escape velocity. That’s one hundred fifty thousand miles per hour. Forty-five miles per second. Nine times faster than the Space Shuttle, six times faster than the fastest moon rockets. Faster than the Voyager spacecraft, which, having reached over 35000 miles per hour, are now leaving the solar system and have for years been claimed to be the fastest man-made objects ever. To which I now say: Pshaw and poppycock — the Pascal-A “manhole cover” in a fraction of a second achieved more than four times the speed it took Voyager 1 decades to attain. TerminalSaint has a new favorite as of 05:59 on Oct 7, 2015 |
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Oct 7, 2015 05:56
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Woolie Wool posted:I've heard that even touching one of the transformers inside a stereo tube amplifier (part of the extremely dangerous procedure known as rebiasing) with improper technique can electrocute you, so Maybe if you're working on it when it's plugged in. If it isn't (and if you've discharged any relevant power caps) you're just touching a hunk of iron and copper. In many setups (I can't speak for tube amps in particular) the iron core of the transformer is typically grounded. If it is you'd be able to touch it all day long, even if it is plugged in. Not that I'd recommend it, there would still be plenty of live terminals that you could slip and touch instead. ullerrm posted:It gets better if you actually watch the video that said clip is from. He cuts the transformer core open and replaces the original secondary winding with a new winding using far fewer coils, then glues the core back together with epoxy. Nothing here is all that bad. If he didn't damage the primary it made the transformer safer, and may have made it more efficient. Replacing the original secondary with much fewer turns makes it so that instead of producing high voltage (~2000v is typical for a microwave.) it would produce around 2v or so. You could touch it's new leads with no problem, (with dry skin, if you've been soaking in water for a while, you might have issues). Yes it can source 100s of amps, but your resistance is such that it can't put it though you. The primary, connected to wall power, is far more dangerous. After that, the next most dangerous thing is touching something too soon after it was welded and burning yourself. The epoxy could even make the transformer more efficient than it had been welded again. Transformers are made of steel lamination to break eddy current paths which would otherwise waste energy. Welding the transformer together electrically connects these lamination and thus creates new paths for the eddy currents. The epoxy would hold the transformer together without creating these eddy current paths. So it's probably a tiny bit more efficient that if he had just welded it back up, any actual gains though would be swamped by things like packing efficiency of the windings and the thickness of insulation on them. So why are they welded in the first place? It's really cheap, strong, cheap, and the welds are pretty shallow and don't rob you of too much energy. A microwave transformer isn't the most efficient design anyway. In a more efficient design the top wouldn't come off in one piece, it'd be many sheets that would be woven into the rest of it. It's hard to describe, so I'm linking a video of the relevant construction. The windings would also be concentric instead stacked. But both of those are more expensive to do. And concentric windings wouldn't let them use magnetic shunts to limit current, which is another cheap and lossy technique.
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Oct 7, 2015 06:17
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TerminalSaint posted:http://savvyparanoia.com/the-fastest-man-made-object-ever-a-nuclear-powered-manhole-cover-true/ Say yes to Project ORION!
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Oct 7, 2015 09:32
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Luneshot posted:In addition, it's one of the basic principles of orbital mechanics that a single impulse from the ground can never put anything into a stable orbit- you can never change where you are, you can only change where you will be. As such, unless you provide at least one extra impulse or circularization burn, your initial "orbit" is always going to intersect the point at which you launched from. Think of Newton's cannonball- no matter how fast you fire it, the projectile is always going to come back around and slam into the back of the cannon. I think part of it is that you use some form of (possibly disposable) aerodynamics to translate some of the upward velocity into orbital velocity during the atmospheric portion of the flight, and maybe use atmospheric skimming to further alter the flight path and prevent re-entry.
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Oct 7, 2015 16:17
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Aurium posted:So why are they welded in the first place? It's really cheap, strong, cheap, and the welds are pretty shallow and don't rob you of too much energy. A microwave transformer isn't the most efficient design anyway. In a more efficient design the top wouldn't come off in one piece, it'd be many sheets that would be woven into the rest of it. It's hard to describe, so I'm linking a video of the relevant construction. The windings would also be concentric instead stacked. But both of those are more expensive to do. And concentric windings wouldn't let them use magnetic shunts to limit current, which is another cheap and lossy technique. Huh, neat. TIL. Thanks for that 
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Oct 7, 2015 16:38
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One Swell Foop posted:I think part of it is that you use some form of (possibly disposable) aerodynamics to translate some of the upward velocity into orbital velocity during the atmospheric portion of the flight, and maybe use atmospheric skimming to further alter the flight path and prevent re-entry. That still will, at best, leave part of your trajectory inside a deep enough part of the atmosphere for aerodynamic control surfaces to be useful. Even on airless worlds, a single impulse can only get you into a stable orbit if it also destroys whatever feature you launched off of, and even then only if it was the tallest thing within [your inclination] degrees of the equator.
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Oct 7, 2015 17:35
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One Swell Foop posted:I think part of it is that you use some form of (possibly disposable) aerodynamics to translate some of the upward velocity into orbital velocity during the atmospheric portion of the flight, and maybe use atmospheric skimming to further alter the flight path and prevent re-entry. Johnny Aztec posted:I can name two people that are as true as they portrayed themselves to be; Mr Rogers, and Carl Sagan. Or, at least, I haven't heard/read about any skeletons in their closet. He and his wife smoked a lot of pot and secretly worked for marijuana decriminalization under pseudonyms, which isn't bad its just surprising that he and everyone else did such a good job keeping it secret so it wouldn't affect his career. His wife was president of NORML. He wanted people to know after he died that he thought cannabis was a wonderful recreational and medicinal substance and its responsible use is better for helping people achieve spiritual insight and tranquility than religion, so  420 smoke dank weed EVERY DAY we are made of star stuff PEACE . Which was only mildly unexpected. He had that serene mid-atlantic accent and everyone kinda assumed.Hahaha Robert Anton Wilson hated his loving guts, I remember RAW liked to put Carl Sagan in his stories because he enjoyed killing him off. In one short story he had Lucifer reach up from Hell and rip Carl Sagan's balls off, just out of nowhere and totally incidental to the rest of the story. This has nothing to do with the topic, I just like that he pissed off RAW that badly. I have never heard a single negative or unpleasant thing about Fred Rogers, he even used to live near me so thousands of locals have I-Met-Mr-Rogers stories to share, and every one is completely wonderful and in character for him. If there was any dirt on him it would have to be so huge that it would have come out by now. 
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Oct 7, 2015 20:49
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Anybody have a source on the Marie Curie being a horrible employer thing? I do not doubt it but would like to read more about.
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Oct 7, 2015 21:07
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Telsa Cola posted:Anybody have a source on the Marie Curie being a horrible employer thing? I do not doubt it but would like to read more about. My source was a youtube video where they visited her original lab in the Paris institute and showed how radioactive all her things are and must've been. They talked about her being a rather harsh woman. But I can't seem to find the video right now.
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Oct 7, 2015 21:26
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Telsa Cola posted:Anybody have a source on the Marie Curie being a horrible employer thing? I do not doubt it but would like to read more about. I was curious about this too. Check this NYTimes story out: http://www.nytimes.com/2014/12/07/magazine/my-great-great-aunt-discovered-francium-and-it-killed-her.html?_r=0 These seem like the most relevant passages though: quote:Perhaps the most tragic demonstration of this involved workers at the United States Radium Corporation factory in Orange, N.J., which in 1917 began hiring young women to paint watch faces with glow-in-the-dark radium paint. The workers were told that the paint was harmless and were encouraged to lick the paintbrushes to make them pointy enough to inscribe small numbers. In the years that followed, the women began to suffer ghoulish physical deterioration. Their jaws melted and ballooned into masses of tumors larger than fists, and cancers riddled their bodies. They developed anemia and necrosis. The sensational court case started — and won — by the dying Radium Girls, as they were called, is a landmark in the history of occupational health. It was settled in June 1928, four months before Marguerite Perey arrived at the Radium Institute to begin a 30-year career of heavy exposure to radiation. Maybe we shouldn't deify this lovely scientist just because she was a woman.
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Oct 7, 2015 21:28
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Cool, thanks to both of you.
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Oct 7, 2015 21:32
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Luneshot posted:Firing a suborbital payload to meet up with a station isn't going to do jack poo poo for you, because you still need to bring those payloads up to orbital velocity for the station to "catch" them- that is, unless your definition of "catch" is "hypervelocity impact". Remember that the difference between reaching orbital altitude and reaching an actual orbit is about 7.5 km/s of sideways velocity. There is a theoretical concept called a skyhook. It's basically a space station that rotates (either in one big piece or through the use of tether cables) so that once in a while part of it is below orbital velocity (or even stationary with respect to the ground, see: cycloid). This way, with precise timing, it could "scoop up" a cannon- or railgun-launched spacecraft and bring it up to orbital velocity. Note "theoretical" in the first sentence: it's completely unfeasible with current technology.
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Oct 7, 2015 22:25
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Mikl posted:Note "theoretical" in the first sentence: it's completely unfeasible with current technology. I assume the forces involved would simply tear apart anything we can make with current materials?
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Oct 8, 2015 01:06
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Humbug Scoolbus posted:Say yes to Project ORION! Unfortunately, until they repeal the test ban treaties and the weaponization of space treaty its very unlikely that we'll get Orion going. What saddens me the most, though, is that Orion is so powerful that we could essentially build a space station here on Earth and lift it to orbit using the Heavy Orion design.
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Oct 8, 2015 01:49
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Using an Orion engine for takeoff would likely be frowned upon. It's for interplanetary travel, not for using inside the atmosphere of a planet you like.
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Oct 8, 2015 05:09
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The Lone Badger posted:Using an Orion engine for takeoff would likely be frowned upon. It's for interplanetary travel, not for using inside the atmosphere of a planet you like. So we should build it on Mars rigth, nothing to like there, lets irradiate Mars in the name of interstellar progress!
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Oct 8, 2015 05:17
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Mikl posted:There is a theoretical concept called a skyhook. It's basically a space station that rotates (either in one big piece or through the use of tether cables) so that once in a while part of it is below orbital velocity (or even stationary with respect to the ground, see: cycloid). This way, with precise timing, it could "scoop up" a cannon- or railgun-launched spacecraft and bring it up to orbital velocity. Also note that picking up the launched spacecraft and putting it onto a new trajectory will also change the space station's orbit, which you'll presumably have to correct somehow.
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Oct 8, 2015 05:43
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Aurium posted:Maybe if you're working on it when it's plugged in. Adjusting the amp while it's powered up is the only way to bias a tube amp. Tube driven guitar amplifiers are the same way. If you aren't 100% sure what you're doing, you run a real and serious risk of injuring/killing yourself.
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Oct 8, 2015 06:23
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The Lone Badger posted:Using an Orion engine for takeoff would likely be frowned upon. It's for interplanetary travel, not for using inside the atmosphere of a planet you like. Actually a water launched Orion is actually one of the things they had been discussing. The nukes are for more effective in atmosphere so the initial launch ones can be smaller, and you want them to be as efficient and clean as possible and were aiming for 0.35 kt yield. A normal warhead that size gives a range of damage when airburst of: Fireball radius: 40 m Air blast radius (20 psi): 200 m Thermal radiation radius (3rd degree burns): 420 m Air blast radius (5 psi): 490 m Radiation radius (500 rem): 0.7 km The Orion would be using shaped-charge fusion boosted fission devices however, with the majority of the blast focused up into the blast plate. You still wouldn't want to be closer than 2 km from the launch point (preferably farther), but the actual zone of damage would be pretty small. It would take about 800 bombs to get a 10,000 ton vessel to LEO. The book, Project Orion: The Atomic Spaceship, by Freeman Dyson is pretty cool. Sample pages on Google Books. https://books.google.com/books?id=r...epage&q&f=false
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Oct 8, 2015 06:37
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Memento posted:I assume the forces involved would simply tear apart anything we can make with current materials? That, and this: Jabor posted:Also note that picking up the launched spacecraft and putting it onto a new trajectory will also change the space station's orbit, which you'll presumably have to correct somehow. I.e.: you still need enough delta-v to actually bring the craft up to orbital velocity, since the craft's and station's speeds would average out. The advantage in this case would be that you could use low thrust engines (ion thrusters, for one) for stationkeeping instead of chemical rockets.
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Oct 8, 2015 06:43
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Perhaps I'm missing something completely obvious, but couldn't you put a small traditional engine on an Orion-launched vessel as a second stage to circularise the orbit? Sure, it wouldn't be as efficient as a purely nuke-powered orbit, but once out of the atmosphere and at the apoapsis you'd only need a relatively modest amount of thrust to establish a proper orbit.
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Oct 8, 2015 11:25
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Definitely. Of course, now you're trying to build a rocket engine robust enough to survive being launched by an orion gun.
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Oct 8, 2015 11:30
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Considering they were talking about launching a whole space station (presumably without it getting smashed to bits) i think that might be considered.
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Oct 8, 2015 13:31
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The accelerations involved in an Orion launch would be pretty modest.  Modern manned launch systems peak out at around 4 Gs of acceleration. Electronics routinely survive many thousands of G of acceleration, dating at least back to the radar proximity fuse in WWII.
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Oct 8, 2015 13:35
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Phanatic posted:The accelerations involved in an Orion launch would be pretty modest. are the reverberations after shutdown just the pusher plate moving back and forth?
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Oct 8, 2015 15:53
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Phanatic posted:The accelerations involved in an Orion launch would be pretty modest. It really is an amazing concept. They can space out the bangs in atmosphere and gradually inject more charges as they accelerate. MazeOfTzeentch posted:are the reverberations after shutdown just the pusher plate moving back and forth? Yes. Other cool things. They found that if a thin coating of oil was sprayed on the pusher plate between blasts, it would vaporize and the plate wouldn't ablate. They did a concept work up for a million ton payload...gently caress launching a space station, let's launch a goddamn city! 
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Oct 8, 2015 16:18
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Mikl posted:I.e.: you still need enough delta-v to actually bring the craft up to orbital velocity, since the craft's and station's speeds would average out. The advantage in this case would be that you could use low thrust engines (ion thrusters, for one) for stationkeeping instead of chemical rockets. Dug up a short story I remembered reading called "Tank Farm Dynamo" about a skyhook made of shuttle ETs. In involves politicians mucking up space exploration and a plucky intern doing something interesting with the station's power system.
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Oct 8, 2015 18:06
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Jabor posted:Also note that picking up the launched spacecraft and putting it onto a new trajectory will also change the space station's orbit, which you'll presumably have to correct somehow. IIRC with the Skyhook the idea is to pair loads going up with ones going down to balance things. Robert Forward describes several different designs in Indistinguishable from Magic, which is an extremely  book.
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Oct 8, 2015 18:50
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I'm pretty sure the guy who was talking about Orion guns was trolling because I've never heard of them before, a quick search didn't turn up anything except people talking about kickstarting an Orion rocket, his source is "no shut up it's totally real," and most importantly it's completely loving stupid. Other than the "you can't get there from here" problem, the reason you'd want an Orion rocket in the first place is that rockets have to carry their fuel with them and need mass-efficient fuel. If you've got a gun on the ground, the amount of propellant isn't a limiting factor and in principle you could still build a megaton gun with regular TNT. The real limits for gun-based acceleration are barrel length and payload durability, which don't have anything to do with nukes. Which isn't to say "stop coming up with ways to make it work" because I love blue sky bullshit and nuclear-powered guns, just that some people are talking about something close to real and others are talking about something very not real and there's some confusion between the two.
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Oct 8, 2015 19:48
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Somewhat more mundane than nuclear rockets, here is one homeowner's nightmare dealing with an old mercury spill. The house apparently used to have a radiant heating system with a device called a Honeywell Heat Generator (search for "honeywell" on the page) which was a mercury-actuated pressure value used to increase the pressure in the system (allowing for higher operating temperature). A previous owner apparently removed the system and spilled all the mercury from the valve in the process without bothering to clean any of it up allowing it to seep throughout the house. Total cleanup cost to the current homeowner was over $50k which his insurance denied because it was an old spill from before he bought the house.
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Oct 9, 2015 04:46
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How about the Salt-Water Rocket? For people who think regular rocket fuel isn't remotely toxic enough.
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Oct 9, 2015 08:57
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Abyssal Squid posted:I'm pretty sure the guy who was talking about Orion guns was trolling because I've never heard of them before, a quick search didn't turn up anything except people talking about kickstarting an Orion rocket, his source is "no shut up it's totally real," and most importantly it's completely loving stupid. Other than the "you can't get there from here" problem, the reason you'd want an Orion rocket in the first place is that rockets have to carry their fuel with them and need mass-efficient fuel. If you've got a gun on the ground, the amount of propellant isn't a limiting factor and in principle you could still build a megaton gun with regular TNT. The real limits for gun-based acceleration are barrel length and payload durability, which don't have anything to do with nukes. Or they just confused space guns and project orion. Easy to do, they're both "Why bother containing the explosion in a rocket?" concepts.
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Oct 9, 2015 10:07
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Abyssal Squid posted:The real limits for gun-based acceleration are barrel length and payload durability, which don't have anything to do with nukes. Nope, speed of sound. A gun propels the projectile by the pressure difference between the inside and the outside, and the pressure wave won't travel faster than the speed of sound in the working fluid. So the highest-velocity guns are light-gas guns; gunpowder gets used to drive a piston, but then the piston works to exert huge pressure on some H2 gas, which is the working fluid, because the speed of sound in H2 is really high, way higher than the speed of sound in burning gunpowder. Phanatic has a new favorite as of 21:09 on Oct 9, 2015 |
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Oct 9, 2015 21:07
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Syd Midnight posted:I've seen one in action in KSP, I cannot find the video anymore but it was a proof-of-concept Orion aircraft with tiny wings that gave it a small amount of pitch and allowed it to roll really well, which was enough to take off from a runway, maintain relatively controlled flight, and crash land within a few km of target. The little cockpit cam of the terrified crew really added to the experience. So I guess if ground-launched nuclear pulse rockets WERE made, airfoils would be an important part of getting them into orbit. That would be the latter part (18:45) of this video by Scott Manley, a.k.a SA's own illectro. I recommend watching the rest of the video as well, because he goes into the nitty-gritty of Orion as well as just how effective it'd be. The airfoils were added simply because  , not because they were actually needed; Orion can give plenty of thrust for a vertical liftoff.Mod is by Nyrath, of Atomic Rockets fame. Beepity Boop has a new favorite as of 18:41 on Oct 10, 2015 |
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Oct 10, 2015 18:27
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Hremsfeld posted:That would be the latter part (18:45) of this video by Scott Manley, a.k.a SA's own illectro. I recommend watching the rest of the video as well, because he goes into the nitty-gritty of Orion as well as just how effective it'd be. The airfoils were added simply because How does the spaceport avoid ceasing to exist during liftoff?
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Oct 10, 2015 22:32
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The Lone Badger posted:How does the spaceport avoid ceasing to exist during liftoff? Because in that version of KSP, damage to buildings wasn't implemented yet. 
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Oct 10, 2015 22:40
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In reality, you mean? From what I recall, the idea is to have nothing of importance anywhere near the launch site; I don't think you'd be using Cape Canaveral for one of these. Shaped charges with efficient payloads or not, you're still talking about a hell of a lot of explosive, radioactive force being thrown around. I'm literally just guessing at this point, but with an Orion system, would you even need to do an equatorial or pole launch? The system seems like it'd be powerful enough to escape the planet on any drat vector it pleases. But I'm probably forgetting something important and that's a very stupid assumption...
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Oct 11, 2015 00:50
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Luneshot posted:Because in that version of KSP, damage to buildings wasn't implemented yet. That avatar and post go together SO well...
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Oct 11, 2015 03:30
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Luneshot posted:Because in that version of KSP, damage to buildings wasn't implemented yet. It is now? Maybe I need to start playing again. 
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Oct 11, 2015 13:01
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Zopotantor posted:It is now? Maybe I need to start playing again. Yep. I recommend [not] using an Orion rocket for SSTO anymore. 
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Oct 11, 2015 22:03
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