NationStates Jolt Archive

OOC:

I have to warn you the following is a lot of loose scribbling on my part. I was hoping any of you rail gun enthusiasts out there who have a penchant for physics might tell me what you think. If I don’t get to much flak out of character then I’ll RP the development and eventual launch of my fully automatic mini-rail gun.

The purpose of this weapon is more physiological then anything but don’t kid yourself with enough ammunition this thing will kick your ass. It’s a next step against missile shields, but as it stands its vulnerability to anti satellite warfare makes it a first strike weapon only. But again if you can put a missile shield up over your country I can put on my satellite. Thoughts? Comments?
(7) v(muz)=(2DF/m)^.5=(2DILB/m)^.5=I(2DLu/m)^.5

v(muz)=Muzzle velocity (Meters/Second)

D=Length of rails (Meters)

F=Force applied (Newtons)

m=Mass of projectile (Kilograms)

I=Current through projectile (Amperes)

L=Width between rails (Meters)

B=Magnetic field strength (Teslas)

u=1.26x10^-6 (The magnetic permeability of free space, Henries/Meter)

Mine:

v(muz)= I(2DLu/m)^.5
v(muz)= I(2D(.5m)(1.26*10^-6)/(455kg)^.5
My variable length of the rails D
Current through projectile I
set D to 200m
set I to 100000000 amps
v(muz)=(100,000,000 amps)(2(200m)(.5m)(1.26*10^-6)/(455))^.5
v(muz)=74,420.84m/s
v(muz)=74.42084km/s

Bullet .5m diametre
.065m^3 Volume
455 kg mass

Electrical Systems:
P= 1,000,000 watts
R= 1e-10 ohms
I= 100000000 amps
E= 0.01 V


Your Inputs:
Distance from Impact: 3000.00 km = 1863.00 miles
Projectile Diameter: 0.10 m = 0.33 ft = 0.00 miles
Projectile Density: 8000 kg/m3
Impact Velocity: 74.42 km/s = 46.22 miles/s
Impact Angle: 90 degrees
Target Density: 1500 kg/m3
Target Type: Crystalline Rock
Energy:
Energy before atmospheric entry: 1.16 x 1010 Joules = 0.28 x 10-5 MegaTons TNT
The average interval between impacts of this size somewhere on Earth is less than 1 month.
Atmospheric Entry:
The projectile lands intact, with a velocity 0.05 km/s = 0.03 miles/s.
The energy lost in the atmosphere is 1.16 x 1010 Joules = 0.28 x 10-5 MegaTons.
Major Global Changes:
The Earth is not strongly disturbed by the impact and loses negligible mass.
The impact does not make a noticeable change in the Earth's rotation period or the tilt of its axis.
The impact does not shift the Earth's orbit noticeably.
Crater Dimensions:
What does this mean?

Transient Crater Diameter: 1 m = 4 ft
Transient Crater Depth: 0 m = 1 ft

Final Crater Diameter: 1 m = 5 ft
Final Crater Depth: 0 m = 1 ft
The crater formed is a simple crater

The floor of the crater is underlain by a lens of broken rock debris (breccia) with a maximum thickness of 0 m = 0 ft.
At this impact velocity ( < 12 km/s), little shock melting of the target occurs.
Thermal Radiation:
What does this mean?

At this impact velocity ( < 15 km/s), little vaporization occurs; no fireball is created, therefore, there is no thermal radiation damage.
Seismic Effects:
What does this mean?

The Richter Scale Magnitude for this impact is less than zero; no seismic shaking will be felt.
Ejecta:
What does this mean?

Most ejecta is blocked by Earth's atmosphere

note the resistance (ohms) used is an approximation of what the resistance of carbon nano tubes in space would conduct at. Does it need to be lower?

Free-form roleplaying game != physics lesson...

Free-form roleplaying game != physics lesson...

Note: Free-form

This is very technical and I can barely begin to understand it, but if you go to this length, you can certainly have a rail-gun in my book :D

Note: Free-form

This is very technical and I can barely begin to understand it, but if you go to this length, you can certainly have a rail-gun in my book :D

Feh, hardly. Most of it is a copy / paste from an online asteroid impact effects calculator. Which calculates him an almighty 5ft x 5ft x <1ft crater in rock. Against something stronger, damage may be almost nothing.

Hardly seems worth the effort of putting it up there.

Just found some neat stuff via Google:

http://www.dstl.gov.uk/pr/science_spot/off_the_rails.htm

http://www.powerlabs.org/railgun.htm

Soooo, you want to put a Rail-gun satillite up to shoot other satillites? It gets a little vague on my scale. Then again I have a massive rail gun inside one of my mountains and no one complained about that, so I can't see any problems.

I used the impact crater calculator because I’d be insane to do them all out by hand, if you’d like I can post the link of the calculator used. As for the formulas for the rail gun I found them at what appears to be a very reliable source and did the calculations myself, I couldn’t find a calculator to do it for me.

As for the target I used 1,500 kg/m^3 because while yes concrete is stronger no one has solid concrete structures, hollow buildings, roads with the undersides removed for piping and cabling yes but only hardened military installations would have that much solid concrete.

As for what this weapon is intended to do…

The hope of this weapon is the next step up in long range devastation. In real life ICBMs are an unstoppable technology, here missile shields seem to be an unfaultable device, so this is a missile shield surpassing technology. The people who use missile shields of unfaultable design usually have fielded very large armies into, reasonably, compact spaces. This would pretty much rain artillery fire down on them from a 90 angle (meaning entrenching yourself would have a minimal effect.) While not by design this could also be used to level a city fairly quickly, though such a grievous act wouldn’t be permissible by my elected officials.

For a little more detail;

There’d be a large central column of non-metal, so as to not interfere with the magnetic fields, with 8 of the rails around it. There’d be a large ‘ammo bin’ above the contraption and each satellite would be able to fire a sizeable amount of iron balls before depletion. With an ammo bin’s dimensions being approximately 100m(l)*100m(w)*400m(h) you could fit 61,538,460 projectiles into it. This mini rail gun isn’t designed to make one large crater but many very quickly because as soon as it fired it’d be designated as hostile and be brought down by the missile shield I seek to circumvent.

Is that a little better? I apologize for anything I might have missed. One thing I’m looking for is how much do you think this little death bringer costs?

I still need to work out a rate of fire, something you guys can help me with.