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A Space Cannon That Might Actually Work
Unequivocal writes "Chalk another one up to Jules Verne. Physicist John Hunter is proposing a space cannon with a new design idea: it's mostly submerged. 'Many engineers have toyed with the [space cannon] concept, but nobody has came up with an actual project that may work. Hunter's idea is simple: Build a cannon near the equator, submerged in the ocean, hooked to a floating rig ... A system like this will cut launch costs from $5,000 per pound to only $250 per pound. It won't launch people into space because of the excessive acceleration, but those guys at the ISS can use it to order pizza and real ice cream.' Though it won't work on people, with launch costs that low, who cares?"
It'll always be more expensive to send people up, at least in the near term, but we will need to send up a lot of other things that could be done in unmanned launches using this or another innovative technology. Ideas such as this could work; it's merely an engineering problem at this point.
I wonder how ice cream would get after those accelerations
The last guy with a plan to build a super-cannon (a Canadian named Bull) did some work for Saddam Hussein. The Israelis didn't like that much, so they murdered him.
I've calculated my velocity with such exquisite precision that I have no idea where I am.
$250.00/lb. for pizza...delivered?
Free, if delivery takes more than 30 minutes...?
I want to order pizza and ice cream on earth, delivered by cannon.
... is a perfectly still part of the ocean with no wildlife and an entire supply system of ships to make sure everything goes right.
it works on people, so long as they're already dead. Why does this matter? Because now I can get the Star Trek space-burial I always wanted!
stuff |
This subject line says it all when it comes to efficiently placing things in low earth orbit.
Here is an interesting "tech talk" at Google where John Hunter explains the workings of the cannon:
http://www.youtube.com/watch?v=1IXYsDdPvbo
If you try to launch an object from the surface of the Earth using a "cannon" the projectile won't be doing anything other than decelerating throughout its flight and this means bringing the projectile to very high velocities where atmospheric heating and stresses become major problems. Then again, launch its self may be a problem as the Hydrogen propelling the projectile is detonating at an extremely high temperature and pressure. Small nitpick as well from TFA:
A big reason space food is what it is instead of the Earthling food we're all accustomed to has to do with keeping the station reasonably clean and experiments doubly so. Crumbs and fluid loose in the station can cause problems.
Sigs are too short to say anything truly profound so read the above post instead.
Since the business end is floating, one could assume that it could be moved. ie: you can aim it. Sure, you could put a pizza into orbit... or not quite.
"Nice, er... gun... you have there."
oh, never mind...
What would the noise do to sea creatures?
To get to LEO, you need about 17,500 mph. The cannon provides 13,000 mph and the earth's orbital rotation provides about 1,000 mph. Where does the remaining 3,500 mph come from?
Why launch pizza and ice cream, which might not withstand the 5000 G acceleration when you can launch a bunch of cubesats or microsatellites. In fact there's a microsatellite(it's name escapes me) up there that's a web server. If you have some amateur radio equipment you can download and upload files to it. It can't store much, only enough for about an email or so. But with improvements in electronics it'll be possible to store even more data on a microsatellite. So eventually the Pirate Bay or Wikileaks or any other dubiously legal website might consider moving some of their servers 'to the stars.'
Correct me if I'm wrong, but 13,000mph isn't fast enough for any kind of stable orbit.
I don't suppose the $250/lb launch costs include the build cost amortized over the lifetime of the system? Or the maintenance costs for that matter. The cost per pound on rockets includes those factors, and far too many people only work up the cost of electricity or whatever when working out the "launch cost" of one of these schemes.
In the end, once you've figured up the total cost of the system it's often more than just using rockets, even though rockets are so terribly inefficient.
I read the internet for the articles.
This rig is where the final fight scene in the next James Bond movie will occur, and you can guess how it might end.
http://en.wikipedia.org/wiki/Project_Babylon
Yes gents, Saddam Hussein could have given us cheap access to space ensuring new area of prosperity for mankind, and era of space colonization...and we killed him!
PS. If a supergun has a basic design similar to German V-3, it might be almost bearable to humans...
One that hath name thou can not otter
Would you like fries with that?
Though it won't work on people...
I'm sure it would launch people just fine.
Wow, that article is horrid. They don't even mention Hunter's startup company: Quicklaunch. On that page you'll find his Google Tech Talk on the subject which answers many of the questions that people are asking here.
How we know is more important than what we know.
I suppose it is a good a plan as any to get the RIAA to fund rail gun development.
It will work on people. It's just that people won't be people if they try. But with that said, I am pretty sure there could be a way. I wonder what would happen if people were heavily pressurized and completely surrounded by liquid? Not so sure they should completely give up on the idea.
I'd be curious to see how deep the cannon needs to be. Being at the equator you'd also have to ship the 'merchandise' to it and then find a way to load it into the cannon. I can't image it would be trivial to load this cannon. Simply dropping it down the canon itself would be one personality. I'm also very curious how the necessary energy would be created to fire this container. I'm all for anything that helps open up the travel off this rock but the one provided link is a little slim on details.
Replacement/bigger ISS or a couple of space elevators could be easier to be built up there if the materials are already available.and is somewhat cheap to get them there.
With the cost to entry being so high right now, and seeing how orbit has been treated mostly as a trash can, I'm not sure we need it being MORE accessible to just anyone...then again, maybe with launches so cheap, they could afford to launch some kind of clean-up vehicles now.
CAn'T CompreHend SARcaSm?
From TFA, it might be about 1km long. It could possibly be a few times longer given depth of oceans. In any case, to get 10km/s, a=50,000ms^-2. and E=25GJ.
So icecream and pizza would certainly get all air pressed out of it. But more challenging would be the launch system. Pressure would be 125MPa or 1250Bar. The fuel will have about 25kJ/Kg@10%efficiency for at total of 1000 tonnes.
If the steel tube d=0.5m, wall thickness would need to be at least 0.5m, so the barrel wold be about 12,500 tonnes excluding stiffening support. That's more than the Eiffel tower.
don't cut it off www.mgmbill.org
What do you mean "Who cares?", I have several people I would like to launch into space cheaply. This product completely misses my needs.
Pretty much anything delivered to your doorstep @ 13,000 mph will be indistinguishable from dog poop. Ya might as well opt for the latter since it's a helluva lot cheaper and can be delivered by the next door neighbor's mutt.
A whole lot of this makes sense, and I like the Google Talk on the topic. I haven't finished it yet, but have a question I haven't seen answered and would like feedback on, why isn't electromagnetic propulsion being considered? The US Navy is looking for railguns to deliver close to 13,000 mph from a ship mounted gun.
B) Eliminate all the stupid users. This is frowned upon by society.
I suspect if this works flawlessly, IF, that space flight in general will be a lot cheaper (even for humans). The big reason for the space shuttle is that it can carry massive amounts cargo with the benefit of people as well. With a cannon that can blast cargo up to orbit, NASA can utilize something like the X prize winners.
Commercial space flight here I come!
Didn't John Hunter work on a land-based project like this in the 1980's?
http://en.wikipedia.org/wiki/Super_High_Altitude_Research_Project
Make it long enough and it CAN launch people. (You'll need good streamlining to avoid nasty deceleration when it leaves the muzzle, though.)
The ocean is DEEP. Something that's roughly neutrally buoyant (i.e. a gun barrel supported by floats distributed along its length) needs to spend negligible structural strength supporting itself. (It only needs to be strong on any part that protrudes from the water - which might be a lot to avoid sinking it when it recoils.) You might want to put "helper combustion chambers" along it periodically to boost and smooth the acceleration if you want to launch live stuff though.
Also you can make it larger diameter and put sabots on the projectile while it's in the barrel to reduce the internal pressure variations or fire very dense loads. (Doesn't really help the materials strength issues, though, because the curvature lessens as diameter rises.)
Recoil? By being submerged it's an inside-out hydraulic shock absorber. B-)
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
You have next door neighbor whose mutt is shitting projectiles at 13,000 mph?
Finally, the problem of cheap space access resolved!
One that hath name thou can not otter
In my experience, pizza holds up less well to acceleration than people do.
A space cannon - if reasonably reusable - would allow for more frequent "launchings", like several times a day.
NASA knows that the turnaround cycle for cargo-only freighters to the ISS right now is too long to respond to emergencies.
Now for any orbital industry to exist, the space cannon would be an ideal way of getting pallets of construction material into near earth space, in order to say, build a space elevator economically, or pre-position material for transfer to an L-5 colony.
For that matter, how else can we even begin to place the material into orbit for a real operational Spacedock for building interplanetary transports?
NASA's ISS is not a sparkling example of meeting contract schedules and budgets.
In actuality, the SeaLaunch semi-submersible former oil-drilling, now orbital launch platform is currently docked due to bankruptcy in Los Angeles Harbor. Given the sea conditions near the Equator, platform stability control is an issue that is well understood.
Given that Lawrence Livermore National Labs has already successfully tested the hyper-velocity hydrogen gas fired cannon at a smaller scale, as seen recently on the Science Channel, the real question becomes, who is really going to step up to the plate to fund and manage the full-scale engineering development project?
I vote on keeping this one with the US Navy. They have a knack for getting big engineering right through appropriate over-design and rigorous inspection, and understanding the political implications of managing the security of the biggest guns at sea. NASA might be allowed to book launch windows, with perhaps a discount on launch fees, but it would have to compete against commercial space payloads booked by FedEx for orbital construction job sites.
Afterall, the first successful anti-satellite operation performed by the US was from Aegis-class Navy destroyers bouncing around in the Bering Straits taking out an out-of-control USAF recon satellite with reprogrammed Raytheon fleet protection missiles.
And, once a technology goes operational, the US Navy never ever buys one of anything for political expedience. They always buy in depth for the long run, for as long, and as hard, as the mission takes.
Let Starfleet be Starfleet!
DarkStarZumaBeachSurfinApocalypseWow
hookers
drug test kit
Glenn Beck
Yes gents, Saddam Hussein could have given us cheap access to space ensuring new area of prosperity for mankind, and era of space colonization...and we killed him!
OR Saddam hired a quack who was assassinated before he was revealed to be a complete phoney.
Had there been something resembling a successful test, I'd say we may have screwed up, but the only mentioned test was a failure. Also I don't hold Saddam's judgment in very high regard, it doesn't sound like there was much peer review on this project, and the US tends to take useful technology and scientific talent from it's enemies rather than destroy it.
Therefore I doubt this was anything that would have been useful, but I suppose we'll probably never be able to verify or deny your conspiracy theory.
oh and $250/pound is bullshit.
If you mod me down, I will become more powerful than you can imagine....
Nope, he just delivers something that LOOKS the same as anything splatted at 13K mph. Meaning, seriously homogenous... can't tell the crust from the meat from the cheese from the sauce. At 13,000 mph, when it splats it's ALL sauce. My neighbor's dog can deliver something indistinguishable without all the fireworks.
The reason space is expensive has more to do with the complexity of the rocket engines and the companies that build them than the propellant. If you want cheap access to space, focus on that. Capital-intensive projects that put heavy wear on their components (like guns) won't make things cheaper. The goal should be to *reduce* the number of parts that need maintenance.
Keeping Saddam from plinking Israel was well worth killing Gerald Bull, though I do appreciate that Saddam was the only person capable of keeping Iraqis from doing to each other what they did after he was removed.
We don't urgently need people (as opposed to machines which are more useful) in space and that nonsense about prosperity for all mankind won't follow from space exploration.
"This post is an artistic work of fiction and falsehood. Only a fool would take anything posted here as fact."
It has to be higher or the climber will pull it down.
From what I remember, they think someone submerged in water could stand up to 50 gravities of acceleration. The gun design is 3600 ft long and the design muzzle velocity is 13,000 MPH. I'm going to make the unreasonable assumption that acceleration is constant, just to get a rough estimate of the G force.
s = 3600 ft ~= 1100 M
v = 13,000 MPH ~= 5800 M/s
s = 1/2 v t, t ~= 0.374 s
s = 1/2 a t^2, a ~= 15,700 M/s^2
Or over 1500 gravities.
Uhm. Either my calcs are off, or that is WAY too much force.
Because Mars is blocking our view of Jupiter.
Have gnu, will travel.
Sorry, but I don't see the benefit of floating the cannon in the ocean. You have a very long structure that must be kept really close to perfectly straight that is subject to currents, waves, coriolis effects, etc. Worse, you are stuck with the projectile emerging into the densest part of the earth's atmosphere.
It would make a lot more sense to build a fixed structure on an appropriate, high mountain near the equator. Places like Peru or Ecuador come to mind as well as Mauna Kea on Hawaii. I'm sure there are more places that would be "developable" and logistically acceptable.
Cheers,
Dave
They that can give up essential liberty to obtain a little temporary safety deserve neither safety nor liberty.
Ben
The man doesn't seem like a quack to me: http://en.wikipedia.org/wiki/Project_HARP
Also, the only mentioned test wasn't exactly a failure what I see; it just revealed some problems, which is understandable with such project.
(and y'know, I was aiming more at Funny...)
One that hath name thou can not otter
... is that it also lets you drop 1000 lb on any spot on the planet (if you don't mind it coming down at 13,000 MPH or so).
So your project ends up as the target of a lot of governmental "gun control" activity.
Look what happened when Iraq tried it (using one that was built into a mountain so it couldn't be aimed at most terrestrial targets): Mossad assassinated the designer mid-project, governments seized critical parts as they were being shipped, and finally the conquering army made them destroy the remainder of the project as a condition of the cease-fire.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
Spoken like a man who has never heard of externalities...
Seriously.
Why should whales get dibs on the whole ocean.
"linux is just DOS with a UNIX like syntax" -- Galactic Dominator (944134)
Plenty of ppl keep ordering Pizza from over the Mexican border that is always so expensive. Gee, Not sure why, but so many ppl like them.
I prefer the "u" in honour as it seems to be missing these days.
Why wasn't this cannon illustration included with the story? ;-)
Quack, quack.
PS. If a supergun has a basic design similar to German V-3, it might be almost bearable to humans...
No. If you work out the G forces required at launch to ballistically get into orbit, solid objects such as electronics will not survive. Live subject would not have a chance.
Tesla was a genius. Edison however was a overrated hack who liked to torture puppies.
How often does NASA use a rocket engine stage before it gets discarded?
I would have thought that replacing something highly complex (like a rocket engine) with something a bit less complex (like a big gun) is exactly the sort of step you seem to be proposing. If you could get stuff into orbit without a rocket, then the rockets required to move it around once it's up there are much cheaper and simpler than anything we use now to get off the surface.
Getting off the planet is really really hard, so anything that makes that simpler is a good thing, even if they don't reach the end game in terms of rocket technology in one step.
I think anybody on Slashdot who refers to Saddam as the martyred hero of space travel is not being serious.
If Saddam had taken half the resources he put into exotic weapons and invested in his conventional forces, he'd be alive today — and probably the most powerful man in the Middle East. But training and equipping armed forces is hard work. A lot of dictators just can't be bothered. Instead they model themselves on the villains in James Bond movies: lots of parties, gloating, glitter, and top secret projects, but none of the dreary stuff that has to do with actual governing.
No. (It will be synchronous because it's tethered but above normal geostationary altitude.) http://en.wikipedia.org/wiki/Space_elevator
First of all, you can't get into stable orbit ballistically; you have to use a rocket motor at apogee of ballistic trajectory, at the least.
Also, we do have clear examples of electronics (from the 60's...) surviving launch to half of orbital velocity from a modified big naval cannon (Project HARP). And that's more or less a "normal" cannon, very short, very high acceleration. Look up V-3; such design can maintain almost constant acceleration, close to average one, and be hypothetically several kilometers long.
So why don't we go totally overboard, and assume a barrel length of 30km; and close to half of orbital velocity (so it will be easier, since there's ^2 in this part of equation ;p) - 3.5 km/s. From simple calculations that gives 20 g. Definitely bearable, as far being launched from a cannon into space goes. With 5 km/s you have 42 g.
Yes, widely unpractical and even...stupid. But I didn't actually suggest using it for humans, just said that it might be almost bearable.
One that hath name thou can not otter
If this launcher is anchored at the surface, how will they compensate for the motion of the waves at the surface? Does that eventually become a non-issue due to the weight of the launcher?
How would they 'catch' the cargo once it was launched into orbit?
How rigid would such a structure need to be, and are there currents in the ocean that would cause bending stress issues between surface and the deepest parts of the structure?
With a pressure suit, you can survive 10gs for a few seconds. Without a suit, 4-6gs is the limit, and only for a few seconds (you cannot breathe and the blood is pushed out of your head.
3 G is really the upper limit for any sustained force. Even 20g from your example is WAY too much.
Tesla was a genius. Edison however was a overrated hack who liked to torture puppies.
Would you like fries with that?
You can make rocket engines that are simpler and more reliable, and effectively don't wear out. What you sacrifice is a bit of performance. But, on balance, the result is cheaper. Liftoff mass doesn't matter (directly); cost does.
I'm advocating replacing complex, high-maintenance, mostly-non-reusable or semi-reusable rocket engines with simpler, lower performance, vastly cheaper, low-maintenance ones. Guns are complex, expensive, and high-maintenance, like current rocket engines. (If you think guns are simple, you haven't looked at the sort of multi-stage high-temperature light gas gun designs required to reach orbital or near-orbital velocities.)
The problem with guns, elevators, pinwheels, launch loops, etc is the spectacularly large capital costs. Guns are worse than most because they're special-purpose (high-g-capable cargo only) and wear out relatively quickly. Most people advocating such designs seem to confound the issue by assuming they can build a reasonably low-overhead business around them, but then comparing to rockets built the way they have been in the past. The fair comparison is to the same budget, spent on rocket R&D and fleet construction, in a low-overhead business. At that point, the rockets look a lot more competitive. (Space elevators are particularly guilty; give me a space-elevator class composite, and I'll give you a pressure-fed SSTO rocket fleet for less capital cost.)
You're missing something. It's not all about maintenance. It's also about construction.
Guns are cheaper to build than airplanes, and airplanes are still cheaper to construct than rockets. The bigger the rocket, the more moving parts it tends to have, the more constraints it tends to have, the more testing it needs. Rockets tend to cost in the billions of dollars for programs, and have floating per unit costs.
On the other hand, a gun is a giant piece of metal (or, more likely in the case a number of very large pieces of metal bolted or welded together). It might wear out, but how many shots do you get before that happens? What is the difference in complexity between building a 8-inch thick, meter radius steel pipe verses the complexity of building a liquid rocket engine, including the turbopumps? What is the time between shots when it actually needs servicing, verses the capital outlay of building the same hypercomplex turbopump (since the odds are pretty damn good you're just going to pitch it into the atmosphere after its 2 minute service life)?
Nobody's laid down the cash for building a serious space gun because space engineers have tunnel vision: Goddard proved liquid rockets would work, and nobody looked back for decades. Now that the technologies have matured, but prices have not significantly lowered, it's probably a good time for investors to invest in innovative startups, and I could definitely see a space gun (or even more likely, a "tunnel-launch" solid-fuel + gun-tube system) going forward.
Sure, it wasn't able to shoot at most targets. Just ones that happened to be 800 miles west of iraq. For example, the entirety of Israel.
You are misinformed (and here you didn't even need to perform any basic calculations...)
http://en.wikipedia.org/wiki/G-force#Human_tolerance_of_g-force // I would venture a guess they were breathing and their brain was supplied with blood // without loss of consciousness or apparent long-term harm. The record for peak experimental horizontal g-force tolerance is held by acceleration pioneer John Stapp, in a series of rocket sled deceleration experiments in which he survived forces up to 46.2 times the force of gravity for less than a second. Stapp suffered lifelong damage to his vision from this test //"this test" likely means eyeballs-out
Early experiments showed that untrained humans were able to tolerate 17 g eyeballs-in (compared to 12 g eyeballs-out) for several minutes
(emphasis mine)
In my hypothetical scenario with 20 g that acceleration would last only 17 seconds, quite bearable. In the overboard example with 42 g, it would last 12 seconds (eyeballs-in!), which still might be survivable (and with eyeballs-in, which stresses eyes less, perhaps even without long-term damage)
One that hath name thou can not otter
No, it never [works]. I mean, these people somehow delude themselves into thinking it might, but... but it might work for us.
I know more than you drink.
On a very small scale, of course: http://en.wikipedia.org/wiki/FGM-148_Javelin
With the first link, the chain is forged.
Dear sir,
If we twisted the cable around the earth, and the cable was connected to the moon on the other end, we could tow the moon back here.
Whichever country it landed on would then be the largest country in the world. (Although it would also be squished.)
We could use this technique to explore space cheaply.
I will authorize funding for space exploration only if this method is used.
Regards,
Your Elected Representative
PS - As a side benefit, we can invade the moon.
-- IANAL, this isn't legal advice, and definitely isn't legal advice for you. Also, Squee!
The original Popular Science article is a much better read and includes additional detail, including the fact that the projectile will experience 5,000G forces. Definitely not for human passengers.
'The tyrant will always find pretext for his tyranny.' - Aesop's Fables
How about we actually fix crap like the POS infrastructures of the world before this dweeb gets Governments to fund his pet project?
What does that remind me of.......
In all seriousness, Saddam only thought he had all of this doomsday projects in the works. The reality, which is supported by evidence apparently (from what I hear), is that most people working for Saddam were terrified of him and his sons and flat out lied or blew smoke up his ass about how far along they were with his ultimate weapons.
The only thing more tragically retarded and pathetic is the fact that a president and some intelligence agencies fell for the same bullshit. Or did they? :)
http://nextbigfuture.com/2010/01/ocean-based-orbital-payload-delivery.html
If he was a phoney why did Mossad murder him?
http://en.wikipedia.org/wiki/Gerald_Bull
http://archives.cbc.ca/politics/national_security/topics/626/ -- historical footage of his work in the past
Great, this could put a whole new light on lost baggage: "Dear Mr. Jones. Your baggage was fired Tuesday. It should have arrived at the ISS before you did. Unfortunately, the capture system failed. The capsule has entered an unstable, atmosphere grazing orbit and will burn upon re-entry in about two weeks. We're sorry, but this loss is covered in the waiver you signed. Sincerely, A. Pratt"
------ The only greater hazard to your liberty than n politicians is n+1 politicians.
A certain scientific SPACEGUN :o)
Barrel wear in guns isn't a big issue when you are dealing with a smooth bore barrel. You can use a barrel for many, many launches, whereas you have to throw away your rocket engine for each and every launch, and rocket engines are a lot more complicated and expensive to build than gun barrels are. Especially smooth bore bun barrels.
The same principle works in multistage gas guns used in things like hypersonic shock tunnels and dynamic compaction of metal powder into solids. It works, but I get the impression that for military things explosives or rockets get the job done with less hassle.
My undergrad thesis supervisor back then worked in the field and actually met this guy at a conference a year or two before he was assassinated.
Uh, the point is not the cost of propellant per se but the cost to lift the propellant that you need to lift the propellant that you need to lift the propellant......... to lift the payload into space. And that ain't cheap.
You're implying the only reason Mossad could have assassinated Bull is that they knew this was going to work? That's about as logical as many conspiracy theorists get I suppose.
Mossad could have killed him for any number of reasons, maybe just to send a message to Saddam. It may well have been that they killed him because they were afraid of the supergun, but even if that were the case, that in no way proves that the thing would have ever worked, as Mossad may have easily made a mistake or killed him without actually finding the truth.
The guns are hilariously complex. After getting the basics down they are much much simpler than multistage rockets.
I wonder how the pizza would look like after delivery.
How long would it take to reach orbit in an elevator?
Need to reach the geosynchronous orbit (22 000 miles).
Fastest car : Bugatti Veyron - Top Speed 253 mph $1,700,00
It would take the fastest car 3.5 days to reach orbit.
But I didn't find the size of the boot for the payload. Maybe it is worth it.
Gerald Bull was no quack:
http://en.wikipedia.org/wiki/Gerald_Bull
If he was a quack, the Israelis wouldn't have murdered him. They would have let Saddam waste his money.
I think anyone on Slashdot who claims that Saddam modelled his lifestyle on James Bond movies is not being serious.
That was Kim Jong Il.
I see a joint venture here, between Starbucks and Pizza Hut. It must be awesome to make like $250 on a single pizza, and $100 on a latte.
no, I don't have a sig
What was it that Hilton had said the price per pound would have to be before they would build a hotel in space?
Exotic weapons? Saddam Hussein? Uh, citation please.
Mind, you, I said the same to Colin Powell...
Aide-toi, le Ciel t'aidera - Jeanne D'Arc.
... also from wikipedia:
http://en.wikipedia.org/wiki/File:Ssb-echo-3.ogg
At the end of the second transmission, you can hear the echo of the last couple of seconds of own signal reflected back from the moon. There's a delay of about 2.7 seconds for a radio wave, travelling at the speed of light, to get from the Earth to the Moon and back. The reason the "direct" signal sounds high-pitched and squeaky and the echo sounds deep and boomy is because the movement of the Moon relative to the ground station on Earth gives about a 300Hz Doppler shift.
as you increase the radius of the cnt, eventually it is larger than nano and becomes micro, and the density decreases faster than the strength. so although they are weaker they have a high enough specific strength to make a space elevator. they can be called colossal carbon nanotubes
although, yes, we dont know how to make one long enough yet, or if they can be joined with a resin, or if single carbon micro tubes are required.
ref: wiki cnts and space elevator
Can't you use the skyhook principle to launch humans into space with this?
Just attach a long cable to the payload with the human (surrounded by spaceship) at the end of the cable. The longer the cable, the more gradual the acceleration.
[Intentionally left blank]
OR Saddam hired a quack who was assassinated before he was revealed to be a complete phoney.
The guy who was hired helped developed the G-5 and G-6 howitzers, which are the howitzers with the furthest range (thanks to base bleed ammunition).
Do you ever read discussions on Wikipedia articles? Maybe you should start.
You made the big mistake of reminding Americans about their miserable failure in Iraq. Vietnam was bad enough, now Iraq, then Afghanistan, Somalia, Yemen etc, etc
if that's the case, why was that scientist assassinated?
---
Space Craft Feed @ Feed Distiller
What about whales? Not just disruption to wildlife, but what about impacts? It will be a sonic beacon to denizens that could bend or break the tube.
I'm hoping all humans can be moved out of the area before launch.
Otherwise if an impact should damage the tube, people manning the surface vessel or platform may find themselves sitting above a quickly rising plume of superhot or exploding hydrogen. An unnoticed kink could turn a barrel of water destined for orbit into a rapidly spreading cone of supersonic shrapnel.
Of course I wasn't really serious.
But you know, as far as the region goes (and disregarding massive external...pressures one or two times), he did quite well...
One that hath name thou can not otter
Space launch guns are not nearly as simple as firearms. The proposals I've seen discussed tend to be things like multi-stage light gas guns, which are anything but simple. They have a variety of parts that must operate at high pressures, temperatures, and velocities. That means the parts tend to wear out. Lab experience of people building such guns (for purposes like high velocity impact testing, metallic hydrogen creation via impact, etc) agrees with this assessment. I'm sure that a production gun, with effort spent on reliability and ease of maintenance, would improve things — but the core problem wouldn't simply vanish.
My point is that rockets don't have to be complicated. Rocket engines currently in use are, and they wear out rapidly. But, a pressure fed rocket can be a very simple device. Fundamentally, it can be done with the only moving parts being the main propellant valves and the valves used to fill and pressurize the tanks. In practice, you'll probably also have a couple valves associated with your reusable igniter, and you may want separate on/off and throttle valves on the main engine, for a total of six valves and five actuators (main valves on a common shaft improves safety and reliability and reduces parts count).
A pure pressure fed rocket is a bit overly simple; it sacrifices too much performance due to low chamber pressure and heavy tanks. But there is a whole world of design space that lies in between the ultra-simple pressure fed rocket and the ultra-complex high pressure turbopumped rockets like the SSME and RD-180. That's the space I'm advocating exploring.
No, that isn't what's expensive. What's expensive is the engines that burn that propellant. And those could get vastly cheaper, if that was a serious design goal. Note that "serious design goal" means a willingness on the part of the engineers to pay for it with reduced performance.
As Elon Musk (of SpaceX) put it, the cost of propellant on a large rocket is less than the accounting errors. And that includes the propellant to lift the propellant.
It's not the barrel that's the hard part (though the barrels tend to wear out too). It's all the valves and compression cylinders associated with getting the propellant gas into the main gun barrel. And the main gun barrel isn't just a smooth bore barrel — at a minimum, it has a bunch of gas inlet ports along its length, with their associated edges.
Light gas guns are most emphatically not the same as simple powder weapons.
Depends on what you mean by exotic. If you mean nuclear, there's not much evidence. Well, there's evidence that Saddam put money into developing them, just no evidence that the money bought anything more complex than a centrifuge. There are, however, numerous documented examples of Iraq using chemical weapons, including some tests on their own population. Specifically, they are known to have had sarin, tabun and VX, and may have had others. He also put a lot of money into developing biological weapons.
As the grandparent points out, if this money had been invested in equipping and training a conventional force instead, he'd probably still be alive and in a strong position. Chemical and biological weapons have almost no tactical utility and very little strategic value. A well-trained and well-equipped conventional army has both.
I am TheRaven on Soylent News
Even if a 1.5 light second long cable were feasible you'd still have to deal with the fact that, as far as I understand, the anchor would have to be in geosynchronous orbit. Since the Moon isn't in geosynchronous orbit, the surface moves relative to the Moon you'd end up winding the cable around the planet.
That would be one phenomenal yo-yo. :-)
I never cease to be amazed of some of the silly things that are published on Slashot.
A system like this will cut launch costs from $5,000 per pound to only $250 per pound. It won't launch people into space because of the excessive acceleration, but those guys at the ISS can use it to order pizza and real ice cream.
The ISS obital inclination is 56 degrees. Any 'ice cream delivery' made from a 0 degree inclination transfer orbit would have a relative velocity of about 7500 mph. The ice cream would effectively become an ASAT weapon.
an ill wind that blows no good
for some reason i read this as "as you increase the radius of the cunt, eventually it is larger...." made for an interesting read :)
Okay fella, you're shooting something at near escape velocity upwards through the thickest part of the atmosphere.
Please calculate the drag on your thingy. Its going Mach 25 through several miles of atmosphere. Calculate its surface temperature and speed by the time it gets to 30,000 feet.
Hint: you can use reciprocity -- look at the performance of similar things in nature, going in the opposite direction, say meteorites.
Rough estimate: 2,500C and 600MPH.
NFG.
Well yes. We still have the receipts for some of those. But he didn't have them at the time. As to conventional forces... I don't think it would have made much difference. The USA had air support. Every time the Iraqis tried to put something in the air or looked like they might, the US blew it to pieces. And anyway, the Iraqi army was never defeated. They just took their uniforms off and the US is still fighting them.
Aide-toi, le Ciel t'aidera - Jeanne D'Arc.
At a savings of $4.7 million ($4750*1000 lbs) per launch seems like a no brainer. It will pay for itself in 105 launches (500M/4.7M), even with only 1 launch a week that is 2 years time. The benefits in safety, fuel, ease of use, are just staggering. We need a Space-Cannon-X-Prize yesterday!
Ah, yeah ... multi stage light gas guns are more complex for sure (VS rail guns). But rockets have to be 'self propelling', that always will add a huge amount of complexity. Also for repeated launches you need to build dozens of these super complex things, you need them to also survive re-entry. Carrying your own fuel explosive fuel at that is also an issue.
So the complexities we don't know (guns) may be less than the ones we are used to (rockets).
whooosh
"If you have nothing to hide, you have nothing to fear." - Every fascist, ever
I can't see an ice cream stand in the middle of the ocean.
Have you worked with rockets? I have, both professionally and as a hobby. The current norm for orbital launchers is hugely complex engines. The vast majority of that complexity is in ultra-high-performance turbopumps and the turbines that drive them. The remainder is a direct result of very high chamber pressures, and a desire to make the chamber and nozzle as light as possible.
At the other extreme, a pressure fed rocket can be very simple. It has two tanks, pressurized either before launch or from a pressurant tank plus regulator and valves. Either is very simple. It then has a main propellant valve for each propellant, an optional throttle valve, and a chamber + nozzle. Additionally, there's an igniter (possibly two for redundancy), with their own (small) valves. That's it. There are no pumps or other high-speed machinery. You keep the chamber pressure low, which reduces heat load and wall stress. All of this adds weight (mostly in the heavier tanks that have to contain the pressure) and reduces Isp, but that was the point — trade those off for reduced cost.
The result is an engine that takes some design work (injectors and cooling passages aren't as complicated as pumps, but they're not trivial either), but where the complexity is all in the shapes of parts that don't actually have to move, and are put under stress levels that are no different than you'd find in your car.
Re-entry is complex, and as yet unsolved; but there are many promising options, including things like replaceable ablative heat shields that use well-tested technology. Explosive fuel is a red herring: rockets explode when the engines fail, not because the fuel decides it feels like it. Industrial users have no trouble moving around quantities of LOX and kerosene comparable or larger than even the largest rockets, without incidents.
The problem isn't that rockets have to be complex; it's just that we insist on building them that way. There are other ways.
Read the actual referenced article for that quote. The quote you give misrepresents the actual results.
The conclusions of that paper show that test subjects are on the verge of blackout at 6-7g on average. Possibility of injury occurs above 15g for any length of time.
No one in their right mind would subject themselves to 20g, unless it was for something like an emergency escape. There is a reason the shuttle is kept at 3g - that is the upper limit for safe g-forces, with some margin.
Tesla was a genius. Edison however was a overrated hack who liked to torture puppies.
He actually had success with smaller scale projects. The US wasn't interested because a large immobile cannon make for an easy target. In an era of lightening war and shock-n-awe, such implements of war are anachronisms.
In fact, the US believed his technology was so likely to succeed that they actively worked to prevent the completion of the project via the CIA, in combination with the Israelis.
There are at least documentaries on this guy's story and almost everyone took his technology seriously.
You can't occupy a country with aircraft. If Iraq had had a real army, yes, the US would still have won. But the war would've been ten times more expensive, from the very beginning. Expensive in money and lives. Even in that climate, it would've been very hard to convince a government and population that it's necessary to go to war when it's apparent from the outset that going to war will cost trillions of dollars and tens of thousands of lives, especially if Saddam hadn't spent so much money on flashy chemical weapons and pretending to have nukes!
The Iraqi Army was 375,000 strong at the outset of the war. And it wasn't killed, it routed en masse because Saddam hadn't spent enough money on wages, or equipment, or training. They didn't take their uniforms off and carry on fighting, they took their uniforms off and went home to the wife and kids. If those guys had stood their ground and fought, and if they were equipped well enough to avoid instant death, the US would've got an extremely bloody nose.
Did well at what? Militarily, Iraq was a joke (Bushie spin notwithstanding) and civil government, while not the worst, did tend towards repression and corruption.
If you mean nuclear, there's not much evidence.
Plenty of evidence of a program, none of any serious progress towards actually building a bomb. The Bushies chose to cherry pick the evidence that justified an invasion, but the evidence itself wasn't fabricated.
Well nothing's clear cut. It's a shame you posted AC as your viewpoint is worth hearing. That's mainly why I'm replying so that people will notice it. Some of the Iraqi army took off their uniforms and went home to their wife and kid. Others joined resistance groups. Others that had gone home to their wife and kids (or whatever family life they had) then later on took up arms again when they realised how bad things were getting - often against their Shia or Sunni neighbours, but usually against the US forces at the same time. The point I was making about the aircraft was that Iraq had no ability to counter it and even if more had been spent on the armed forces, they couldn't stop the US from striking any target it wished. And given that, I think you would have seen the same desertion even if they had been more numerous, better paid or equipped. They knew that they were going to lose. At least in any kind of traditional warfare. You might be right, but I'm a bit surprised people are suddenly coming up with this notion that if Saddam had allocated resources from chemical weapons to traditional military spending Iraq would suddenly have put up a much stronger fight. Is this a new meme being born? We can't argue conclusively without examining things in a lot more detail though, so I don't object to being told I'm wrong about it.
I do disagree about it being harder for the US government to bring the country to war if Iraq had spent more money on its military. The war has cost many lives and an ever growing debt and that was enough for us. Millions of us marched in our capitals to oppose the war and were ignored. We knew what would happen and we said what would happen. I doubt anything Saddam had done would have made any difference to our governments actions.
Aide-toi, le Ciel t'aidera - Jeanne D'Arc.
Was it really that big of a joke? (considering the area!) It survived a decade long war with Iran, it was able to take on almost any other regional power. Only external forces humiliated it militarily.
As for governing...I'm not saying in the least that it was roses (me being from a place with its own history of repression and corruption - BTW, don't think even for a second those things ended in Iraq). But it's telling that it would be hard to present a strong argument why it was really worse in Iraq back then, in comparison to how it is now (or vice versa).
One that hath name thou can not otter
I don't think it would have made much difference. The USA had air support.
This isn't about who could beat who in a conventional fight. There isn't anybody left who could beat the U.S. on those terms. (Notice that all armed opposition to the U.S. now consists of non-sovereign entities using guerrilla warfare and terrorism.) But that doesn't mean nobody can thumb their nose at the U.S. If you have a strong military you can dominate your region, enlist allies, and make it very expensive for anybody to attack. That doesn't mean that nobody can beat you, just that the cost of beating you is too high.
Wow, it's almost as if you read the sentence immediately after the one that you quoted.
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Yes, they survived the Iran-Iraq war — just barely. Recall that Iran was in something of a mess at the time. That's why Saddam invaded — he was sure they were a pushover. But despite grossly mismatched forces, massive international support (including the U.S.!), and social disorder in Iran (which prevented them from even having a unified command structure!), it took him 5 years just to achieve a 3-year stalemate. Not exactly a testament to his military leadership.
There's more to the two conventional wars between Iraq and the U.S. than the fact that they were mismatches. Even allowing for the difference in resources, the collapse of the Iraqi side managed to shock and surprise U.S. commanders and their allies.
I'd be the last to defend the current government in Iraq. But that was a result of the U.S. toppling Saddam without any plan (beyond Paul Wolfowitz's magical thinking) as to what would happen next. The result was something like a civil war combined with a return to feudalism combined with an occupying army. They're only now recovering from that. But that doesn't make Saddam's government any less ugly and inept.
Yeah, right, I can see the headline now "ISS shot down with frozen Thanksgiving turkey!!"
Sure, it wasn't able to shoot at most targets. Just ones that happened to be 800 miles west of iraq. For example, the entirety of Israel.
Unless I've missed something, Project Babylon (at the time of the apparent assassination) had so far only constructed a single, horizontal (i.e. no elevation) test barrel and the two that were planned were (disguised as?) satellite launchers - which means they were pointed EAST.
(Not to say that there weren't plans to ACTUALLY build them pointed another direction. And of course if you have enough delta-v on the projectile for full orbital capability it's trivial to re-tweak it to drop the projectile where you want it in a wide area around your own location after going around the long way.)
The POINT, however, had nothing to do with whether Saddam really was planning to use it to attack Israel.
The POINT is that ANY orbital gun has such potential. (And THIS ONE could hit pretty much anything with trivial aiming). Or at least it has enough such potential that governments may roadblock its construction or take out the project or its personnel in a preemptive strike to avoid upsetting the balance of power that currently benefits them.
Same applies to private space launchers of any type, of course. But doing it with big "guns" immediately gets civilian officials thinking in terms of "being shot at".
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
The problems involved in boosting the cable to orbit, dropping it back down, etc. are part of what make the "space fountain" design interesting.
Of course, it has its own set of problems to deal with...