# Could a coil gun's projectile escape earth's gravity?

If there were a Coil Gun, that was built to go across the United States and Canada border, for 2000km in a horizontal line, that would end at the end of a 'tunnel,' the projectile should hit escape velocity 11.2km/s and be out of the earth's gravity's field?

Coil gun launch cost
964 MEGA watts
10 cents per kwh (wholesale) from a power station
\$9,640,000.00 per launch

NASA Space Shuttle launch cost
Q. How much does it cost to launch a Space Shuttle?
A. The average cost to launch a Space Shuttle is about \$450 million per mission

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Octataral3 years ago
I don't understand why the coilgun has to be in a straight line, why not run in a loop similar to the LHC until reaching escape velocity?
LiquidLightning7 years ago
In theory it should work, however there are a few problems with this design:
-acceleration in coilguns is super fast, so you would probably die from that.
-Electromagnetic fields intense enough to propel a space shuttle to escape velocity would WRECK your nervous system.
-All of the iron in you body would shoot towards a single point, rupturing arteries, veins, capilarys, and muscles.
Also, when you calculated the cost for the launch, i believe that you forgot to count in the cost of the space shuttle itself, the production costs for the "tunnel", and all of the legal work involved.
All in all however, i think that this is a great idea. Nice work.
7 years ago
No, Coil guns, or EM guns can be designed to accelerate relatively gently. The EM fields are not proportional to velocity. The iron in your blood would stay tightly bound in your body. The forces acting on it are a fraction of those caused by the acceleration you're under.
7 years ago
That is true, however, if you wanted to accelerate at safe speeds, you would need the tunnel to be much longer.
7 years ago
From another comment I made on railguns

Not necessarily. If you accept an acceleration of say 3g, which is bearable, you could be at escape velocity in 6.2 minutes, after travelling 2000 km! The practical sustainable human g limit reference is about 4.5g, so then the ramp is only 1300 km long...... I've just seen references to John Stapp's work in High-g experiments - and he discovered that humans can sustain 17g (!!!) "eyeballs in" - or pushed into your seat.....for at least several minutes... 17g : 65 seconds to escape velocity :368km of track. 1 tonne: 964 MEGA watts....ignoring air friction. Or more than half the entire output of a conventional powerstation of a minute Sheesh, what are we waiting for ?

nfarrow (author)  LiquidLightning7 years ago

Design Problem Fixes:

-Super speeds can be controlled with any kind of electronic setup. Example: rollercoaster’s are controlled to start and stop and travail at desirable speeds. So if the projectile is slowly (less than 5g) accelerated at a constant rate but not a lethal rate therefore I would think the only problem would be the space (runway) needed not how fast you can accelerate to your destination.

- Electromagnetic radiation can been fixed by using Electromagnetic Shielding and also heat problems can be cooled by using some kind of Thermoelectric Effect since in something of the size of this project you would almost have unlimited amounts of electrical energy.

- I excluded the cost for the projectile since I was assuming just getting something to space without the need of a rocket fuel would be tremendously helpful in pricing.

-Also I did not add the cost of NASA creation of the space shuttle from the 1960 since it’s reusable and that I would have to add inflation to the total price since \$1 in the 1960s was worth way more then it is now. And I would take a lot of research tying to find information on NASA’s creation.

(Extra Info)

Starting from lets say “Ross International Airport” and ending at “Piney Pinecreek Border Airportdistance of 726 mi

My guess would be that a normal human can take no more then 50m/s² (5 g). So the acceleration can only be less than that.

Max speed for human passengers in 726mi runway

Formula: v2 = u2 + 2as

726 mi = 1,168,383.74 meters

Distance=1,168,383.74 meters

Acceleration 50 m/s2

Final Velocity being 10809.180 m/s

Initial Velocity = 0 m/s

Traditional Space Shuttle top speed

Speed: 7,743 m/s (27,870 km/h; 17,320 mph)

7 years ago
Actually yea, I completely forgot about electromagnetic shielding. However, wouldn't the shuttle be pressed against the bottom of the tunnel? I guess that means that you would need a means of holding it upright, and I am pretty sure that electromagnets are the only option. This will drastically add to the energy costs.
Furthermore, the launch vehicle would need to be made from mostly ferrous materials, which are significantly heavier than the alloys currently in use on shuttles, this would mean that the coilgun and the electromagnets holding up the shuttle would require much more power, FURTHER adding to energy consumption.
I think that's it, but feel free to tell me if there's anything that i missed. =)
7 years ago
Oh, and i do not believe that the coilgun will keep accelerating the projectile for the entire trip, as the shuttle will become magnetically saturated, and will remain at a constant speed once it has reached that point.
steveastrouk7 years ago
Your speed of light is wrong, its 300 MILLION metres/sec
and you're completely ignoring relativistic effects.