Gigantic Air Gun To Blast Cargo Into Orbit 384
Hugh Pickens writes: "The New Scientist reports that with a hat tip to Jules Verne's From the Earth to the Moon , physicist John Hunter has outlined the design of a gigantic gun that could slash the cost of putting cargo into orbit. At the Space Investment Summit in Boston last week, Hunter described the design for a 1.1-kilometer-long gun that he says could launch 450-kilogram payloads at 6 kilometers per second. A small rocket engine would then boost the projectile into low-Earth orbit. The gun would cost $500 million to build, says Hunter, but individual launch costs would be lower than current methods. 'We think it's at least a factor of 10 cheaper than anything else,' Hunter says. The gun is based on the SHARP (Super High Altitude Research Project) light gas gun Hunter helped to build in the 1990s while at the Lawrence Livermore National Laboratory (LLNL) in California. With a barrel 47 meters long, it used compressed hydrogen gas to fire projectiles weighing a few kilograms at speeds of up to 3 kilometers per second."
Pumpkins (Score:5, Funny)
Re:Pumpkins (Score:5, Funny)
Into orbit. RTFH before posting. ;)
Put one on the ISS (Score:3, Interesting)
The cost would be higher, of course, but I'm sure obtaining funding would be even easier. The ground-based version would be a necessary stage
Re:Put one on the ISS (Score:4, Funny)
You using that euphemism for shit or corpses? Because if it's corpses sign me up.
Re:Put one on the ISS (Score:5, Funny)
Since it would be used only for eco-friendly recycling, it could not possibly be considered a weapon of any sort.
I'm sure this is what medieval siege engineers shouted at the unhappy garrisons of besieged castles they were bombarding with decaying horse corpses: "That's no weapon, we're just recycling!"
Re:Pumpkins (Score:5, Funny)
Re:Pumpkins (Score:5, Informative)
Re:Pumpkins (Score:5, Funny)
http://digg.com/odd_stuff/Huge_Cannon_Fires_Pumpkins_at_600_MPH_VIDEO [digg.com]
It hit the top of digg yesterday
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A catapult uses a spring of some sort.
A trebuchet uses a falling weight.
The idea of the long barreled cannon is that it can spread out the acceleration of the object over its travel down the length of the barrel, rather than relying on a short rapid acceleration that would be likely to cause damage.
G-forces ???? (Score:5, Interesting)
Just wondering how they plan to address the problem of controlling the G-forces and prevent damages to the cargo.
The cannon idea was tried before ...... not a test single cargo survived the trip (or made it to orbit).
Re:G-forces ???? (Score:5, Informative)
If you RTA (yes I know, not likely), you'll see that they acknowledge this issue, their intent is to use this for robust cargo only (rocket fuel is given as an example, not e.g. satellites or humans). They also state that ablative heatshields would be necessary to survive atmospheric transit, so wouldn't be a fully reusable vehicle either. Sounds like one for the back burner, as it isn't solving the current launch capability issues.
Re:G-forces ???? (Score:5, Insightful)
If you RTA (yes I know, not likely), you'll see that they acknowledge this issue, their intent is to use this for robust cargo only (rocket fuel is given as an example, not e.g. satellites or humans)
Send up consumables, for sure. Fuel, water, compressed air, freeze-dried food, etc. Even if just used for that, this is not a bad plan. There's no rule that says you have to use only ONE method to get stuff off-planet.
Short-term Project (Score:4, Interesting)
Send up consumables, for sure. Fuel, water, compressed air, freeze-dried food, etc. Even if just used for that, this is not a bad plan. There's no rule that says you have to use only ONE method to get stuff off-planet.
One good criticism would be that this is a short-term project. You'll need conventional lift to get the tools up into space to build an orbital mining facility. This air-gun can be used to lift all the materials that those tools will use to build the mining facility and fuel for the crafts that will go get the asteroids and coax them back. But once that's done, we ought not need the air gun nearly as much or at all.
Still, compared to the costs of things like shuttles or ISS, this is pocket change.
Re:Short-term Project (Score:5, Insightful)
You'll need conventional lift to get the tools up into space to build an orbital mining facility. This air-gun can be used to lift all the materials that those tools will use to build the mining facility and fuel for the crafts that will go get the asteroids and coax them back. But once that's done, we ought not need the air gun nearly as much or at all.
Depends on what you're planning, really. If your goal is to actually spread the human race out from Earth, this could be used long-term. Just keep sending up loads of water and compressed air, etc., for however long you can afford to do so. Keep the stuff in a stable orbit and just leave it there for however long you need (years, no problem, really). Once you're ready to use it (in LEO, at a Lagrange point, on the Moon, Mars, etc), move it to where you need it, as the most costly part of getting it into orbit has already been done.
That's one of the biggest problems with the U.S. space programs, the lack of long-term thinking and planning (and funding for a long-term strategy).
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Just keep sending up loads of water and compressed air, etc., for however long you can afford to do so
I've heard it argued by folks who sounded like they knew their stuff that it's much cheaper to do it by dragging in asteroids (maybe one with a cubic mile of ice in it) than to shoot it up from earth. I admit, I haven't seen the numbers.
And, yes, it seems unlikely that governments will get this done.
Re:Short-term Project (Score:5, Insightful)
I've heard it argued by folks who sounded like they knew their stuff that it's much cheaper to do it by dragging in asteroids (maybe one with a cubic mile of ice in it) than to shoot it up from earth. I admit, I haven't seen the numbers.
Considering we just hit the Moon to try to figure out how much water ice is there, it seems unlikely that we have any good ideas on which asteroids have water ice in them, much less the ability to bring them to where we need them (yet). That's more the type of project I'd expect a few decades _after_ we do what this project is talking about. All in good time, my friend...
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Considering we just hit the Moon to try to figure out how much water ice is there, it seems unlikely that we have any good ideas on which asteroids have water ice in them
Some progress on that front:
http://www.usnews.com/science/articles/2009/10/08/ice-confirmed-on-an-asteroid.html [usnews.com]
much less the ability to bring them to where we need them (yet)
Yeah, I think smart folks feel it's a pretty straight-forward, if slow, proposition, but we'd have to still design and build the actual devices. Heck, convincing the p
Re:G-forces ???? (Score:5, Interesting)
Actually, the ability to cheaply fill fuel depots in orbit does a significant amount to reduce the problems associated with current launch technology. Consider Apollo. The massive Saturn V rocket was required because in addition to taking the CM, SM, and LM to orbit, it also had to take the fuel to get it from LEO to the moon -- fuel was the most significant fraction of the mass (2:1 or 3:1 if I remember correctly). Instead, if this had been available to move fuel to orbit on the cheap, you could have used a couple of Saturn IB rockets and rendezvoused in LEO with a freshly filled Earth departure stage. I wouldn't be surprised if it would have been able to cut the cost of Apollo in half. This could also allow a new moon mission architecture without the massive Ares V.
Remember, space missions are like exponential Russian nesting dolls. If you remove a layer (in my example, the EDS), you can reduce the initial launch mass drastically. This is why things like ISRU and various electric propulsion schemes are such hot topics, even though they don't help you get off the ground either.
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It had to be said.
Re:We Don't Need Fuel in Orbit (Score:4, Insightful)
You work with what you have.
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Why don't you just say what you really mean: "Waaahhh! Our laws of physics SUCK! I don't believe in them."
Actually, I'm probably confusing you with another poster who spams about his free-energy fantasies. If you're just talking about beanstalks and solar sails, well, maybe, but I think "fuel" and "reaction mass" are going to be the central part of our intra-system arsenal for quite a long time.
OK, apparently I'm NOT confused, spammer. (Score:2)
Whoops, missed your post downthread. Please ignore my second paragraph.
Re:G-forces ???? (Score:5, Interesting)
Actually, it solves a LOT of current issues. Maneuvering fuel, food, water, and medicines for example are quite durable under G-force. Those are a large part of what the ISS resupply missions are carrying. The Progress mission hardware isn't reusable either but is likely considerably more expensive than a solid booster with a dumb cargo capsule.
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I've got one question. How much air are we moving to launch something?
My suspicion is something in the range or Cubic Kilometers per Second instead of CFM and if we're talking that much, what impact on our weather is there going to be with such a large fan running all the time?
What I'd suggest instead is use the tube and combine it with maglev. Allows much better control of the thrust (more accurate) and might remove the solid rocket booster stage for orbit. You also get income from the reactors excess powe
Re:G-forces ???? (Score:5, Informative)
It's not even 1 Km^2 total, even if the final pressure in the tube was 3000 atm. Certainly not enough to change the weather.
The beauty of the system is it's very simple which translates to inexpensive (for something of that scale anyway). The engine for orbit is based mostly on the need to take the most direct practical path out of the atmosphere rather than start out on an orbital trajectory.
I'm thinking it'll be a solid fuel engine to withstand the launch stresses and to be inexpensive and reliable.
The idea is to avoid costly precision. Just shoot it up there, track it's orbit and go get it. (yeah, not quite THAT simple...)
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once again, you come here claiming to know things that make us all look stupid, and yet all you can actually say of it is ridiculous predictions with no evidence whatsoever (other than the aforementioned 'you are all stupid and i'm not' type nonsense)... perhaps you have been spending too much time with 'dr' gene ray, the 'worlds wisest human' (self proclaimed of course - www.timecube.com ). your arguments are very similar to his. show us one bit of evidence that this 'lattice' is real, and, more importantl
Re:I See. Yet Another Cockamamie Scheme... (Score:4, Funny)
"It's an energy field created by all living things. It surrounds us, penetrates us, and binds the galaxy together."
Yes that sounds similar!
We need to master the lattice and soon we will be able to jump really high, move shit with our minds, and battle each other with laser swords.
Re:I See. Yet Another Cockamamie Scheme... (Score:4, Informative)
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Re:G-forces ???? (Score:4, Interesting)
They probably hope to discover "inertia canceling."
I could not find it in the article, so:
What are the power requirements for such a mechanism?
Where will it be located?
What about ITAR issues?
Why not make it longer for smaller accelerations?
The concerns about the hypersonic regime of fluid flow should not be an issue if they fire from a mountain, there are a hand full of craft that can handle the plasma, although none accelerate like that at such a low altitude.
Aside, what happens to fuel (liquid and solid) under such high g-load? I can find no studies on it.
P.S. I am an Aerospace Engineer.
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The importance this stuff will be lighten the load on a conventional launch vehicle elsewhere. Saving substantial ammount of money.
Re:G-forces ???? (Score:5, Informative)
You won't ride to orbit on this, but there's lots of stuff that doesn't have to worry about being pulped on launch.
Go up thread and read about artillery shells. (Score:2)
n/t
Starting to get afordable (Score:3, Funny)
At 450 kilos you can launch three people with breathing gear and parachutes. Think of it as the "Econo" version of space tourism.
Re: (Score:2, Informative)
Only if you want them to arrive on orbit as people paste. The G-forces in a cannon launch would be very high.
Re:Starting to get afordable (Score:5, Funny)
Only if you want them to arrive on orbit as people paste. The G-forces in a cannon launch would be very high.
I'll make a list...
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Only if you want them to arrive on orbit as people paste. The G-forces in a cannon launch would be very high.
I'll make a list...
screw the breathing gear! make it 4 people, my list is too big!
Re:Starting to get afordable (Score:4, Funny)
he's making a list
and checking it twice
he's gonna find out
who's been naughty or nice
Gerald Bull is coming to town...
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Well pack them up in bubblewrap. Lots and lots of bubblewrap.
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Only if you want them to arrive on orbit as people paste.
Scotty wouldn't have minded this technique. At least he would not have been spread across Puget Sound by a rocket failure. http://en.wikipedia.org/wiki/James_Doohan [wikipedia.org]
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Don't forget the big floppy shoes, polka dot cover-alls, and big red rubber noses.
Is that a gigantic air gun ... (Score:5, Funny)
Is that a gigantic air gun with a 1km barrel in your classified launch facility, or are you just happy to see me?
This will also be used at sporting events (Score:2, Funny)
To shoot t-shirts into the crowd. Casualties are expected.
Gerald Bull (Score:5, Interesting)
Gerald Bull was Canadian engineer who died (bullet in the head) trying to build such a cannon.
See http://en.wikipedia.org/wiki/Project_HARP [wikipedia.org]
Re:Gerald Bull (Score:5, Informative)
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http://www.globalsecurity.org/wmd/world/iraq/other.htm
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Supposedly a "supergun". But like the rest of Iraqs' WMDs, it may may have been mythical. It's really not that absurd that Saddam would actually want a facility to launch peaceful satellites. I mean, the guy was a dictator, but he liked money; having a facility to hire out would have given him the cash to build even more palaces for himself.
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Re:Gerald Bull (Score:5, Interesting)
Bull was killed by Mossad because he was helping Iraq build a "supergun". You make it sound like he was killed because of Project HARP.
Gerald Bull designed his "super gun" to put payloads into orbit. He approached the US government with the idea and they rejected it as a launch method but wanted a weapon. Disgusted and disillusioned (he was apparently treated very poorly) his response was to create a truly powerful weapon. Iraq hired him to build one for them. The Mossad killed him in Belgium, a country that exports arms all over the world. It's important to remember that the US military has done this with a number of inventions. The guy who invented the x-ray laser had wanted to use it for medical purposes; excising tumours etc. The US military classified it and now it's a weapon. Another Canadian invented polymorphic encryption for secure banking and corporate communications...US military classified his work and as far as I know he can't even talk about it with his peers.
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"Gerald Bull designed his "super gun" to put payloads into orbit. He approached the US government with the idea and they rejected it as a launch method but wanted a weapon. Disgusted and disillusioned (he was apparently treated very poorly) his response was to create a truly powerful weapon. Iraq hired him to build one for them. The Mossad killed him in Belgium, a country that exports arms all over the world."
100% unadulterated bullshit. The US Government sponsored his work in HARP, and it set altitude rec
Re:Gerald Bull (Score:4)
But that's way too obvious a reason... it was a conspiracy by the very groups who stood to benefit from reduced launch costs that killed him. Mm-hmm.
If this was useless, it would already be funded (Score:4, Interesting)
$500 million is what BART wants to spend to build a 3.2 mile stretch of elevated rail to connect the Oakland Coliseum to the Oakland Airport, and this boondoggle of a project is already funded. Imagine the progress we would make towards space travel if we spent the same amount of money on technology that will move cargo into space as opposed to moving people too lazy to take the already existing BART Shuttle to the airport?
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Imagine the progress we would make towards space travel if we spent the same amount of money on technology that will move cargo into space as opposed to moving people too lazy to take the already existing BART Shuttle to the airport?
"Cargo" is a very broad term.
You're pretty much limited to solids, liquids, or solids immersed in liquid. Anything with air inside it will crumple in an instant and even solid state electronics probably won't be able to take the insane acceleration.
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$500 million is what BART wants to spend to build a 3.2 mile stretch of elevated rail to connect the Oakland Coliseum to the Oakland Airport, and this boondoggle of a project is already funded.
Cool! You mean, when I fly my private plane into Oakland to see a game or concert at the Coliseum, I won't have to wait 10 minutes for the free shuttle to come and get me? That will make my life so much different for the better... worth every penny of that 500 million dollars!
G force. (Score:4, Interesting)
I may be wrong in this calculation but running the numbers I get a weird result.
The gun is 1.1K long with a final velocity of 3km/s.
So the payload would be in the gun for 1.1/(3/2) = 0.73 seconds.
In that 0.73 seconds the payload would accelerate to 3 kms/sec The continuous acceleration would be 3000/9.8/0.73= 417 Gs. That is sure a lot of Gs. Much more than the 3.2 the shuttle produces.
Re:G force. (Score:5, Informative)
The acceleration is an artillery piece runs to the thousands of Gs. Artillery shells are full of explosives, electronics, and machinery. This gun should be able to handle pretty much all of the consumables and many of the parts and materials needed by the space station.
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Then there is this idea that you could build a kind of linear accelerator by firing a stream of pellets in the direction of (say) Saturn. Your vehicle can be a toroid which rides the pellet stream, pushing them backwards.
this has real potential...for certain things (Score:2)
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Delicate electronics aboard satellites would obviously not fare too well with such high acceleration
How delicate - are we talking about vacuum tubes, with their little feathery grids and filaments? I think the term "delicate" doesn't really apply to electronics any more, or rather doesn't have to. You couldn't use modular circuit boards, of course - you'd snap the connectors off. Or any sort of what we'd consider normal PC electronics, such as pluggable cables or rotating components such as disks or fans. They're built to be easy to build, and to modify.
But custom electronics, single-board stuff and
Re:this has real potential...for certain things (Score:5, Informative)
With discrete component electronics you just pot the whole thing in epoxy. I don't know how well that works with integrated circuits -- the point of failure is likely to be the fine wires that connect the chip to the package leads, although those may be light enough that the real concern is vibration rather than steady G force. Even vacuum tubes can be built tough, if they're built small.
But ~400 Gs (per calculations by a poster above) is nothing. The radio proximity fuzes in WW II antiaircraft projectiles didn't use transistors, and had to withstand ~20,000 Gs when fired and ~5,000 Gs of shell spin.
1670 g (Score:4, Interesting)
All you need is a booster rocket (and a cargo) which can stand 1670 g of acceleration (possibly higher, if the gun does not provide uniform acceleration.)
v^2 = u^2 + 2*a*S
u=0, v=6000, S=1100 => a=16,364 m/s^2 = 1670g
Re:1670 g (Score:5, Informative)
Which, given that artillery shells exceed 2000g and are full of explosives, electronics, and machinery, should be easy.
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What machinery exists inside an artillery shell?
All kinds of gadgets, for example a timing mechanism so that the shell's explosive charge doesn't go off inside the gun.
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Fusing to ignite the main explosive charge, whatever linkages were needed to make the various settings. Early naval shells had some time delay, so that the explosion happened after the shell had had time to penetrate the armour of the other ship. WWII anti air craft shells had some combination of mechanical and electric/electronic control to detect the proximity of an aircraft, and explode near the aircraft, rather than the older time delay fusing ( which itself would have required some mechanical method
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> What I always wondered was if the aircraft carrier had not come along, would
> we have seen some terminal guidance systems for naval and land artillery?
We did. The US Army had artillery shells with terminal guidance in the 1970s.
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"We did. The US Army had artillery shells with terminal guidance in the 1970s."
I never heard of it. What did it home on? ( or can you say? )
Re:1670 g (Score:4, Insightful)
The one I read about in the seventies had optics in it but there were no specifics about what it homed in on. Later I heard about one that homed on a laser target designator but I don't know if it was the same device. I would expect them to be using GPS now.
What is interesting is that the electronics were not potted. They simply used thick boards supported all the way around the edge and made sure all the parts were installed in contact with the board (i.e., not standing up on their leads). This was the seventies so the parts were DIPs, discrete transistors, quarter watt resistors, etc. Modern surface mount parts should be more robust yet.
I see no major problem shipping most stuff that the station needs via this gun. Some equipment might need to be more robust than usual, but so what? The reason for making such things as light as possible is to save on launch costs. If this thing is 1/10 the cost of conventional rockets you can double the weight of your experiment to make it tough enough to survive the gun and still come out way ahead.
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I believe that there are laser and GPS guided artillery shells which have terminal guidance.
Launch loop (Score:2, Interesting)
A helping hand? (Score:2)
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Operation Paperclip got the Nazis, and it helped get Americans to the moon.
The Mossad, uhh, "got" the guy who built the Iraqi super gun.
Re:A helping hand? (Score:4, Funny)
I like my eggs over easy.... (Score:2)
Why gas? (Score:2)
Wouldn't a rail acceleration ramp (railgun) be better suited for this purpose? At least I can imagine that it would distribute the starting acceleration a lot better. With this thing you'll have difficulties keeping the stuff together you want to catapult up.
Re:Why gas? (Score:4, Informative)
That's booking it (Score:2)
fire projectiles weighing a few kilograms at speeds of up to 3 kilometers per second.
That's in the neighborhood of 9,480 feet per second. About twice the speed of a high velocity bullet. A projectile weighing kilograms going twice the speed of a bullet.
Who besides me wants to forget the space thing and launch those projectiles against ground targets?
All that matters (Score:5, Funny)
As a tax-payer, I refuse to fund it unless it makes a cool "FffffummmppPPP" sound.
Not nearly enough (Score:4, Insightful)
1. In round numbers:
. ~9.5 km/sec to LEO (given, approximate)
. ~6.0 km/sec from gas gun (FTA)
. ~0.5 km/sec atmospheric drag (FTA)
= ~4.0 km/sec needed from projectile rocket
. 350s ISP for projectile rocket (assumed, optimistic)
= 0.69 propellant fraction
. 450Kg projectile (FTA)
= 310Kg projectile rocket propellant
= 140Kg projectile non-propellant
. ???Kg projectile structure, motor, etc.
= ???Kg net cargo to LEO (in any case, 140Kg)
2. Assuming you want to rondezvous with something in an established orbit (e.g., the ISS), any significant orbital maneuvering is out of the question; in paticular an orbital plane change--whether by the projectile or the target--as it's too expensive.
That limits the number of launch windows. You can't simply launch projectiles into orbit as fast as the gun can fire, otherwise you'll end up with them scattered in various orbits that you have to chase down (again, very expensive).
E.g., there are nominally 2 launch windows/day for Shuttle flights from KSC to the ISS. (Due to various rules, in practice it's limited to 1/day, but we'll ignore that.)
3. Even with optimal launch parameters, orbital rondezvous is still non-trivial, and one reason why even unmanned ISS resuplly vehicles are much more than simply a dumb ballistic container, and have, e.g., OMS and RCS motors, propellant and the weight/complexity/cost penalties that come with them.
Which is why larger, more infrequent and expensive missions will remain the norm for the foreseeable future--with or without a space gun or its ilk.
4. In short, we need an orbital infrastructure that can handle smaller/dumber vehicles. That doesn't exist, and few if any of these proposals account for it. With, e.g., a group of ion/electric tugs it may make more sense. That is, something that can cost-effectively collect those smaller/dumber vehicles and bring them to where they're needed.
I've met Hunter, and visited the SHARP gun (Score:4, Interesting)
Back when I was doing giant space gun work at Boeing :-). Feel free to ask questions. I'm not about to type in several volumes of technical data, but it's nice to see he's converged on the same muzzle velocity we came up with (5.7km/s).
Our desigh: particle-bed heater with Aluminum-oxide heat storage (it's actually #20 sandpaper grit). It's much easier to store hydrogen at room temperature, then heat it just before it hits the barrel. Using small particles, you get lots of area for heat transfer. The particle bed gets warmed up with heaters of your choice over a period of hours, then you fire the gun and in a second or so transfer a good chunk of that heat to the hydrogen.
Why heat the hydrogen? The speed of sound of a gas depends on the molecular weight and temperature, and hot hydrogen works best. The efficiency of a gun drops dramatically as you reach the speed of sound of the working gas. Think of it this way, speed of sound is how fast pressure waves travel.
If the projectile outruns that speed, there is no way for the gas at the back end to send push to the projectile further up the barrel. It's a bit more complicated than that since you are constantly feeding gas from the back end, and the gas right near the projectile is moving almost as fast, so pressure waves can catch up, but on the whole as you get near Mach 1 of the gas, your ability to push drops way down.
Depending on size of the gun, and where you are launching to, the west slope of Hawaii and the Andes are good locations. The first has *long* even slopes, courtesy of lava flows. The second are shorter, steeper slopes, but somewhat higher altitude (less air to fly through), and closer to the equator.
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Part 2:
Our projectile was re-useable liquid fueled. And the mission was to feed a fuel depot for geosynchronus satellites. 3/4 of the mass of comsats in low orbit is fuel to get them to GEO, and stationkeeping for 15 years. The projectile was very simple, pressure fed liquid engine. It used part of the fuel to get itself into orbit, the remainder is transferred to a fuel depot.
The projectile uses GPS nav borrowed from artillery shells to get to the close vicinity of the depot, then the depot has the sma
Old ideas are new again (Score:3, Interesting)
When I first read this, I was thinking of HARP, the (rather obvious) precursor to the SHARP program [wikipedia.org]. His goal of making HARP a space launch platform was a failure, but the lead engineer (Gerald Bull) was so disgusted with the politics, he went on to created Project Babylon for Iraq [wikipedia.org]. I suppose the moral of the story is: keep the big gun makers employed, or they will go work for someone else :)
Back to the original topic: from the press release, they've doubled the velocity achieved by HARP. If that is true, then it's only a small hop with a booster rocket to LEO. This could really work!
Re:nothing new here (Score:5, Informative)
Bullshit. Several weapon systems do just that, including the rocket assisted howitzer shells [wikipedia.org] used in the M109 Paladin [wikipedia.org].
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If we try hard enough we should be able to think up a form of rocket fuel that survives the transit. Oh, there it is: water ice. Just freeze a slug and toss it up to the satellite with solar power to be remanufactured into oxygen and hydrogen for use as a fuel or breathable air or potable water while in orbit.
The idea works better shooting from Mars, but whatever...
TFA, my good sir: (Score:3, Informative)
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or explosive materials (fuel)
Fuel isn't explosive. Fuel-oxidizer mixes, or some monopropellants, may be explosive, but are not necessarily shock-sensitive. This would be fine for launching suitably-built canisters of fuel or water, or other insensitive cargoes.
And don't overestimate the sensitivity of some electronics packages -- gun-fired projectiles with electronic fuses are a decades-old technology.
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And don't overestimate the sensitivity of some electronics packages -- gun-fired projectiles with electronic fuses are a decades-old technology.
And the newer ones are laser guided, I believe. So it has en entire guidance system in the projectile.
Re:nothing new here (Score:5, Interesting)
Matterafact, the proximity-fuzed antiaircraft shells of WW2 had a vacuum tube in them.
rj
Re:nothing new here (Score:5, Informative)
> Cargo it seems would have a better chance but any sensitive equipment (like
> 99% of anything used in space) or explosive materials (fuel) wouldn't be able
> to be shot up in a gun.
Nonsense. Guns have been firing projectiles filled with explosives for centuries. The US Army has had shells filled not only with explosives but optics, electronics, and actuators for terminal guidance for dacades. In WWII they had anti-aircraft guns that fired shells with vacuum tube proximity detonators in them. In WWI they used shells with self-winding mechanical timers. Fuel would be easy.
Re:NOT a Railgun (Score:4, Funny)
With enough duct tape over any likely orifices, I don't see why not. I still don't think they would survive launch though.
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Of course, you just need to remember that your duct tape doesn't need to be able to withstand the full forces, it just needs to be stronger than the parts of you which are not orifices.
Re: (Score:2)
With launch speed on 6km/s that is an average speed of 3km/s over a 1.1 km tube giving a time of 1.1/3s. With the change in speed being 6km/s or 6000m/s this gives acceleration of 44200 m/s^2. g is about 10m/s^2 so that makes it about 4420g. Given that most people pass out at about 10g I think this answers your question.
Re: (Score:3, Interesting)
Rail guns have other issues right now, such as the rai
Re: (Score:2)
Assuming initial cost + interest at 5% as you posit, you have a total of $625 million after 5 years.
Carrying costs are therefore $31.5 million annually thereafter.
Even allotting for only 225 kg/shot, that's 2.25 million a shot available.
1 firing a day, 5 day work week, at $10k/kg is more than half a billion of revenue in the first year.
If they did like airplane owners, and ran it 7 days a week, 1 firing a day yields $821 million the first year.
30,000 firings @10,000/kg would be $67.5 BILLION. Yo
Re: (Score:2)
Re: (Score:2)
225 kg * $10,000 per kilo = $2,250,000, not $225,000. You're off by an order of magnitude.
Here, lets make it simple:
225 kg x $1 per kg = $225.00
225 kg x $10 per kg = $2,250.00
225 kg x $100 per kg = $22,500.00
225 kg x $1,000 per kg = $225,000.00
225 kg x $1,0000 per kg = $2,250,000.00
Like I said, you dropped a decimal place.
Re:Saddam already tried just that (Score:5, Informative)
Search for Gerald Bull [wikipedia.org] and read abut his super-gun project.
Re:Gravity (Score:4, Informative)
It saves a great deal of fuel by getting the rocket needed to achieve the remaining velocity going 3km/sec and above the atmosphere.
Re:Your official guide to the Jigaboo presidency (Score:4, Funny)
Ah I love the smell of terrified redneck racist in the morning it smells like victory!
Still I pity your need to overcompensate for your inadequacies.