Space supergun
Discussion
Not going to work for a launch from the surface of the earth - or any body that has a reasonable atmosphere. An object leaving the barrel of a gun would have to be travelling at orbital velocity as it exits the barrel. For earth, that means 17,500 mph. In fact, to overcome atmospheric drag near the surface of the earth, it would need to be travelling even faster than that so that by the time it reached the top of the atmopshere it still retained at least a speed of 17,500 mph parallel to the earth's surface.
The vast bulk of man made objects would simply melt due to atmosphetric friction long before they'd managed to get above the atmosphere.
It might work on an airless body, such as the moon or an asteroid.
The vast bulk of man made objects would simply melt due to atmosphetric friction long before they'd managed to get above the atmosphere.
It might work on an airless body, such as the moon or an asteroid.
There are studies that investigate the idea of using an electro-magnetic "rail gun" to launch sturdy payloads (fuel, water, powefully built company directors, etc.) into orbit, but that uses something more akin to a track than a traditional gun barrel and one big bang.
It was mooted that if a "space tugs" were in use in low earth orbit, refuelling and repositioning satellites, then the rail gun could present a cost effective solution to re-supplying the space tugs; if you lost a few payloads of fuel then it wouldn't be too much of an economic loss.
For the reasons given by Eric, I am not convinced it really is a runner for a planet like Earth, which has such a deep gravity well. If we want to lift payloads from the Moon (if we were mining Helium 3 for example) then it might work well.
It was mooted that if a "space tugs" were in use in low earth orbit, refuelling and repositioning satellites, then the rail gun could present a cost effective solution to re-supplying the space tugs; if you lost a few payloads of fuel then it wouldn't be too much of an economic loss.
For the reasons given by Eric, I am not convinced it really is a runner for a planet like Earth, which has such a deep gravity well. If we want to lift payloads from the Moon (if we were mining Helium 3 for example) then it might work well.
LittleSwill said:
I recently saw a program saying that you could develop a supergun to cheaply fire non-fragile objects (water, oxygen, chicken and leak soup) into space. Is it doable or a load of rubbish?
Got one in the garden now you mention it. Quicker than dropping my boy to school by bus
Buff Mchugelarge said:
LittleSwill said:
I recently saw a program saying that you could develop a supergun to cheaply fire non-fragile objects (water, oxygen, chicken and leak soup) into space. Is it doable or a load of rubbish?
Got one in the garden now you mention it. Quicker than dropping my boy to school by bus
Wasn't there something called the HARP or SHARP gun or similar? Something like that. Basically a large scale conventional gun.
Km/s projectile speeds. Acceleration would also be brutal!!!
Rail guns have their own problems. Like the power/energy storage and avoiding melting of the rails due to the incredibly high currents. Maybe you could tone it down from a weapon style to something larger and longer with more gradual power input and gentler acceleration.
I can't imagine you'd have much control over where or even if it gets to orbit.
Space elevator seems a better bet. If that would work.
Km/s projectile speeds. Acceleration would also be brutal!!!
Rail guns have their own problems. Like the power/energy storage and avoiding melting of the rails due to the incredibly high currents. Maybe you could tone it down from a weapon style to something larger and longer with more gradual power input and gentler acceleration.
I can't imagine you'd have much control over where or even if it gets to orbit.
Space elevator seems a better bet. If that would work.
you need a thunderwell.
http://atomicrockets.posterous.com/thunder-well
http://atomicrockets.posterous.com/thunder-well
Edited by dudleybloke on Saturday 21st January 17:57
Eric Mc said:
Buff Mchugelarge said:
LittleSwill said:
I recently saw a program saying that you could develop a supergun to cheaply fire non-fragile objects (water, oxygen, chicken and leak soup) into space. Is it doable or a load of rubbish?
Got one in the garden now you mention it. Quicker than dropping my boy to school by bus
Anything you can do to reduce the weight of fuel you need to carry must potentially make sense, a rail gun has the advantage that you can accelerate slowly - adding speed along the launch track rather than a big bang in the breeches.
Although NASA have issuesd a press release, which is usually a good sign that it's rubbish.
maffski said:
That's not nice, lots of children suffer from acne!
Anything you can do to reduce the weight of fuel you need to carry must potentially make sense, a rail gun has the advantage that you can accelerate slowly - adding speed along the launch track rather than a big bang in the breeches.
Although NASA have issuesd a press release, which is usually a good sign that it's rubbish.
Rail launch is one of those ideas that is great on paper, but financially and technically flawed.Anything you can do to reduce the weight of fuel you need to carry must potentially make sense, a rail gun has the advantage that you can accelerate slowly - adding speed along the launch track rather than a big bang in the breeches.
Although NASA have issuesd a press release, which is usually a good sign that it's rubbish.
The maximum deltaV you could probably run is about 500-600mph. Supersonic is not impossible, but impractical due to the sonic boom. So you still need to find your other 17,000mph of deltaV.
As a result the rocket/spaceplane would still have to be huge!
Skylon is the best of the current active development programs imo.
It's intended to be SSTO and fully reusable, not to mention British.
annodomini2 said:
Rail launch is one of those ideas that is great on paper, but financially and technically flawed.
The maximum deltaV you could probably run is about 500-600mph. Supersonic is not impossible, but impractical due to the sonic boom. So you still need to find your other 17,000mph of deltaV.
As a result the rocket/spaceplane would still have to be huge!
That NASA article says that the rail gets you the first 600mph, which is enough to launch a vehicle that uses SCRAM jets. My understanding of a SCRAM jet is that it's similar to a normal gas turbine engine on a plane, except that it doesn't actually use a spinning compressor and turbine. Instead it just has a tapering combustion chamber so incoming air is compressed by the shape of the engine. This allows it to operate at very very high speeds and high altitudes, but the SCRAM jet doesn't work at low speed, hence the requirement for the rail launch. The article goes on to say that the actual payload would be rocket launched from the SCRAM jet vehicle once it reaches the edge of space.The maximum deltaV you could probably run is about 500-600mph. Supersonic is not impossible, but impractical due to the sonic boom. So you still need to find your other 17,000mph of deltaV.
As a result the rocket/spaceplane would still have to be huge!
I didn't see any fundamental flaws. (Not saying I can knock one up in the garden like, but doesn't sound implausible.)
jingars said:
I read a rant by an American about the Navy buying their railguns from foreign companies. Most of them were British 
mrmr96 said:
annodomini2 said:
Rail launch is one of those ideas that is great on paper, but financially and technically flawed.
The maximum deltaV you could probably run is about 500-600mph. Supersonic is not impossible, but impractical due to the sonic boom. So you still need to find your other 17,000mph of deltaV.
As a result the rocket/spaceplane would still have to be huge!
That NASA article says that the rail gets you the first 600mph, which is enough to launch a vehicle that uses SCRAM jets. My understanding of a SCRAM jet is that it's similar to a normal gas turbine engine on a plane, except that it doesn't actually use a spinning compressor and turbine. Instead it just has a tapering combustion chamber so incoming air is compressed by the shape of the engine. This allows it to operate at very very high speeds and high altitudes, but the SCRAM jet doesn't work at low speed, hence the requirement for the rail launch. The article goes on to say that the actual payload would be rocket launched from the SCRAM jet vehicle once it reaches the edge of space.The maximum deltaV you could probably run is about 500-600mph. Supersonic is not impossible, but impractical due to the sonic boom. So you still need to find your other 17,000mph of deltaV.
As a result the rocket/spaceplane would still have to be huge!
I didn't see any fundamental flaws. (Not saying I can knock one up in the garden like, but doesn't sound implausible.)
A RAM jet would would, but would struggle to go supersonic, a SRAM may work at these speeds, but you would need a SRAM and then a SCRAM jet to see major benefits.
Then you need a conventional rocket to get you into orbit.
The issue is the launcher gets more and more complex. You're back to the same issues that blighted the shuttle.
The more systems you add, the more complex the total system becomes and the increased likelyhood of failure goes up exponentially.
Additionally if these systems are not off the shelf tech then these need to be developed, adding to the cost. More systems and that cost gets muliplied.
EDLT said:
I read a rant by an American about the Navy buying their railguns from foreign companies. Most of them were British
I was talking with an ex-Army tank driver around eight years ago, and he mentioned whilst drunk, that he had spent a couple of years on a tank trialing team testing lots of stuff on how to improve the tanks. Most of it was mundane things like adding extra hooks on the deck so screens can be put up to shield crew on top of it from the sun, what extra bits could make the crew's lives easier, stuff like that, but he did mention that he had been involved with trialing rail guns on the tanks, that sounded pretty interesting!Gassing Station | Science! | Top of Page | What's New | My Stuff