Rail gun or space cannon to launch to Orbit

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bdewoody

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I have seen these methods briefly mentioned and then dismissed as a means to get people into orbit. Regarding a cannon I guess it would have to be designed to not exceed 6-8 Gs of acceleration and yet develope enough velocity to achieve orbit. With the rail gun using magnetism to accelerate again at a rate less than 10G I wonder how long a track would be necessary.
Is either of these methods plausible as a means of getting humans into orbit or will they only be practical to deliver cargo?
 
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sftommy

Guest
Most maglev ideas are posited on helping in the initial stage of launch
although I've often wondered how long a maglev track would have to be to achieve escape velocity (25,000 mph)?

back in 2002 CNN carried an article on NASA's maglev efforts which were about to run out of funding:
http://archives.cnn.com/2002/TECH/space ... index.html
 
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MeteorWayne

Guest
One problem you didn't mention is that if you travel from the surface at orbital velocity, you will instantly be incinerated.
 
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SteveCNC

Guest
can you imagine the sonic boom that would cause ? Some of you may never have experienced a sonic boom since for the most part aircraft aren't allowed to go mach1+ over populated areas anymore . Back in the 60s they did it all the time , sometimes it would startle the crap out of you lol but I can only imagine what 25000mph in lower atmosphere would do , at least till it disintegrated .

Still need an engine no matter how you look at it , a rail gun might be able to do an assist , like an aircraft carrier launch only vertical but an engine would have to fire on time for it to work . Probably ok for cargo but I doubt it would be good for humans .
 
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bdewoody

Guest
Oh yes I failed to mention that the launch site would have to be on top of a very tall mountain and that the craft would have to have some boost capability of it's own.
 
V

Valcan

Guest
bdewoody":165qmznf said:
Oh yes I failed to mention that the launch site would have to be on top of a very tall mountain and that the craft would have to have some boost capability of it's own.
Theres that team with the space cannon idea. Though there is alot of hurtles to overcome it sounds interesting.

I dont know about the railgun idea. I think atleast for large or anything that is fragile-US-your stuck to fire sticks.
 
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HopDavid

Guest
bdewoody":cniblc69 said:
Oh yes I failed to mention that the launch site would have to be on top of a very tall mountain and that the craft would have to have some boost capability of it's own.
Atmospheric abuse scales with V^3 p, where p is density.

Density at the top of Mt. Chimborazo is about .5 that of sea level.

Let Vs be maximum speed sea level. Let Vc be maximum speed at top of Chimborazo

(Vc)^3 * .5 p = (Vs)^3 * p
(Vc)^3 = (Vs)^3 * p/(.5 p)
(Vc)^3 = 2 * (Vs)^3
Vc = 2^(1/3) * Vs
Vc = 1.26 Vs

So you can go 26% percent faster at the top of Mt. Chimborazo.

The Japanese mag lev trains don't go over 600 km/hour because of friction and drag. That's about .167 km/sec.

1.26 * .167 km/sec = .21 km/sec. Let's round up to .25 km/sec since I'm lazy.

Let's say the payload was shot straight up and there's not atmosphere resistance. .25 km/sec would take you about 3.1 kilometers higher than the top of Chimborazo.

You need to reach an altitude 70 kilometers or higher before you can make your orbital burn.

If your aim is to circumvent the gravity/drag penalty imposed by the atmosphere, a maglev up Chimborazo doesn't cut the mustard.
 
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SteveCNC

Guest
for a good example of a workable railgun type system check out Superman ride

I've been on that ride a few times and the acceleration is really smooth all magnetically driven .
 
H

HopDavid

Guest
SteveCNC":3cyxu0r9 said:
for a good example of a workable railgun type system check out Superman ride

I've been on that ride a few times and the acceleration is really smooth all magnetically driven .
I think railguns could be a great way to launch stuff.

On an airless world.
 
A

a_lost_packet_

Guest
HopDavid":uuu2vyzb said:
I think railguns could be a great way to launch stuff.

On an airless world.
I agree. In fact, if and when we develop the ability to extract resources in space, I think it would be the preferred means for shuttling them around. It may not be the quickest method but, it would be very economical. So, a load of ore that needs processing would be rail launched to intersect with a processing platform. Minimal fuel would be necessary for course correction firings and retrieval and capture. A continuing stream of rail-launched packages may take months/years to reach the central platform but, once they arrived they'd be arriving like clockwork, on a known schedule... hopefully. Manufacturing the casings for the EM system to interact with would be the first major bit of business for primary miners/robots. So, that might hold things up for a bit. A Lunar colony might be able to support initial efforts on Mars using such a system, depending upon the availability of suitable raw materials to construct the launch casings.
 
O

orionrider

Guest
You don't need to accelerate all the way to orbital velocity to gain from a rail gun or similar system. :idea:

Imagine you build a railway track on the 30° slope of Mount Kilimanjaro (near the Equator). Put a 'normal' rocket on a high-speed train; accelerate horizontally before climbing the mountain. Ignite the rocket and launch it where the track curves down, so that the load is greatly reduced. If the rocket is released at 960kph and 5,900m altitude (AMSL), that is nearly 60 seconds into a 'normal' launch sequence, just before Max-Q.

In the theoretical case of launching the Space Shuttle, you would spare about half of the SRB's burn (more than 500 tons of propellant) and more than 100 ton on the external tank. Needless to say, the gain in payload would be enormous!

In 2007 a French TGV was tested at 575km/h (357MPH) on a normal passenger track. Improving the design in order to reach the desired speed and payload for a small to medium rocket must certainly be possible. The development costs would be high, but after that the system would be fully reusable, with several launches per day.

In the long term, more ambitious maglev or air-cushion systems could be built, bringing larger rockets to (supersonic?) velocity.
 
J

Jazman1985

Guest
Imagine you build a railway track on the 30° slope of Mount Kilimanjaro (near the Equator). Put a 'normal' rocket on a high-speed train; accelerate horizontally before climbing the mountain. Ignite the rocket and launch it where the track curves down, so that the load is greatly reduced. If the rocket is released at 960kph and 5,900m altitude (AMSL), that is nearly 60 seconds into a 'normal' launch sequence, just before Max-Q.
People are always looking for ways to build a SSTO vehicle, this is one of several ways to make it (more) feasible.
 
Z

ZiraldoAerospace

Guest
I think the best way to do this would be to use the maglev launcher to get the ship past the thickest part of the atmosphere, and just decrease the amount of fuel that the ship needs to carry, not do the whole job on its own. If the railgun could accelerate the ship to, say, Mach 10, that would help to reduce the fuel needs quite a lot.
 
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scottb50

Guest
sftommy":18tsztgy said:
Most maglev ideas are posited on helping in the initial stage of launch
although I've often wondered how long a maglev track would have to be to achieve escape velocity (25,000 mph)?

back in 2002 CNN carried an article on NASA's maglev efforts which were about to run out of funding:
http://archives.cnn.com/2002/TECH/space ... index.html
I doubt they can float and 25,000 mph would get pretty toasty. It might work in orbit though, a race track to build up speed then launch pretty much anywhere, would cut propellant enough to make deorbit engines feasible. A conventional launcher and assent/landing vehicle to LEO maglev Stations, at the moon brake into a big orbit and descend to the surface for landing, power up with engines to the maglev, refuel for Earth orbital capture and descent to a LEO Station. Returning to Earth on an assent/landing vehicle.
 
F

Floridian

Guest
bdewoody":135xmuhn said:
I have seen these methods briefly mentioned and then dismissed as a means to get people into orbit. Regarding a cannon I guess it would have to be designed to not exceed 6-8 Gs of acceleration and yet develope enough velocity to achieve orbit. With the rail gun using magnetism to accelerate again at a rate less than 10G I wonder how long a track would be necessary.
Is either of these methods plausible as a means of getting humans into orbit or will they only be practical to deliver cargo?
I believe that cargo-loads that don't have humans on board can survive in excess of 6-8 Gs.

Sadly, nothing that out of the box will ever be tried by NASA. They refuse to step out of the box and try new things.
 
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EarthlingX

Guest
This seams related :

http://www.defenseindustrydaily.com : US Navy Producing Scaled-Down Rail Gun Naval Weapon


Back in March 2006, BAE Systems received a contract for “design and production of the 32 MJ Laboratory Launcher for the U.S. Navy.” Some hint of what they are talking about can be gleaned from the name. The project is an electro-magnetic rail gun that accelerates a projectile to incredibly high speeds without using explosives.
...


and posted in various other threads :
www.nasa.gov : Emerging Technologies May Fuel Revolutionary Launcher
 
A

annodomini2

Guest
orionrider":2ltc5e53 said:
You don't need to accelerate all the way to orbital velocity to gain from a rail gun or similar system. :idea:

Imagine you build a railway track on the 30° slope of Mount Kilimanjaro (near the Equator). Put a 'normal' rocket on a high-speed train; accelerate horizontally before climbing the mountain. Ignite the rocket and launch it where the track curves down, so that the load is greatly reduced. If the rocket is released at 960kph and 5,900m altitude (AMSL), that is nearly 60 seconds into a 'normal' launch sequence, just before Max-Q.

In the theoretical case of launching the Space Shuttle, you would spare about half of the SRB's burn (more than 500 tons of propellant) and more than 100 ton on the external tank. Needless to say, the gain in payload would be enormous!

In 2007 a French TGV was tested at 575km/h (357MPH) on a normal passenger track. Improving the design in order to reach the desired speed and payload for a small to medium rocket must certainly be possible. The development costs would be high, but after that the system would be fully reusable, with several launches per day.

In the long term, more ambitious maglev or air-cushion systems could be built, bringing larger rockets to (supersonic?) velocity.
There are commercial maglev trains that will do 600mph.

I believe there are prototype systems that have achieved much higher
 
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orionrider

Guest
There are commercial maglev trains that will do 600mph.
I believe there are prototype systems that have achieved much higher
No, there are not. China has plans for a 600MPH maglev in low pressure tubes, but no prototype, not even a planning.

From Wikipedia: http://en.wikipedia.org/wiki/High-speed_rail
High-speed rail (HSR) is a type of passenger rail transport that operates significantly faster than the normal speed of rail traffic. Specific definitions by the European Union include 200 km/h (120 mph) for upgraded track and 250 km/h (160 mph) or faster for new track.[1] In Japan, Shinkansen lines run at speeds in excess of 260 km/h (160 mph) and are built using standard gauge track with no at-grade crossings.[2] In China, high-speed conventional rail lines operate at top speeds of 350 km/h (220 mph),[3] and one maglev line reaches speeds of 431 km/h (268 mph). The world record for conventional high-speed rail is held by SNCF's TGV which clocked 574.8 km/h (357.2 mph) on a test run.
Not only the speed is important, but also the payload. High speed trains are designed to transport 50 tons or so, not 300...
 
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EarthlingX

Guest
You may also want to check this :
Wiki : Land speed record for rail vehicles
Determination of the fastest rail vehicle in the world varies depending on the definition of "rail".

The Japanese JR-Maglev is the fastest non-conventional train in the world, having achieved 581 km/h (361 mph) on a magnetic-levitation track. Unmanned rocket sleds that ride on rails have reached over 10,400 km/h (6,462 mph), equivalent to Mach 8.5. The fastest manned rail vehicle was a manned rocket sled, that travelled at 1,017 km/h (635 mph).
The French TGV (Train à Grande Vitesse) is the fastest conventional train in the world, using powered metal wheels riding on metal rails. In April 2007, the TGV broke its own 1990 record with a speed of 574.8 km/h (357.18 mph) under test conditions with a shortened train (two power cars and three passenger cars) and larger wheels to reduce angular speed in the motors.[1]

The fastest scheduled trains in daily service is the Chinese CRH service Harmony express on the Wuhan–Guangzhou High-Speed Railway[2]
 
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flyer456654

Guest
A vertical track could eliminate the problem with going high speed at a low atmosphere...by vertical I mean a freaking huge tower probably 30km would do it...which is totally impractical....
 
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Astro_Robert

Guest
Earlier Earthling referenced a possible railgun system used as a Navy artillery weapon. There are actually other applications that have been in development, which does tend to lend credence to the idea that some sort of rail launch assist could be feasible.

Specifically, some years ago a small company developed this technology for small arms fire. Metal Storm, stacks projectiles in a barrel and can fire them at increadibly high rate not achievable with chemical systems. They have been trying to sell it to the US-Navy for a number of years.

http://www.metalstorm.com/component/option,com_frontpage/Itemid,79/

It not directly related to launch, but does indicate the general basis of the technology.
 
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neilsox

Guest
There is little doubt that a "space" cannon or rail gun can serve as the first (or 2nd) stage to orbit, but the economics are doubtful. Even 10 kilometers above sea level at 7200 kilometers per hour = 2 kilometers per second, air friction losses are huge and the skin gets white hot. Cost rises rapidly at more than 10 kilometers altitude, even if a jumbo jet is used as the launch platform. Neil
 
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