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The US Navy's Railgun Program
RougeFive writes "Imagine a warship weapon that can launch projectiles at Mach 10 without explosives (more than three times the muzzle speed of an M16 rifle), that has a range of 220 miles and that uses the enormous speed to destroy the target by causing as much damage as a Tomahawk missile. Meet the U.S. Navy's electromagnetic railgun program."
Why is the summary written like we haven't heard about this before.
http://tech.slashdot.org/story/10/12/11/046205/navy-tests-mach-8-electromagnetic-railgun
http://tech.slashdot.org/story/12/02/08/152224/us-navy-receives-first-industry-built-railgun-prototype
In and of itself.. this article is very lacking and at face value is old news. We have been developing railguns for a long time. We have the principles down, but the problem comes with the energy needed to really run a weapons effective version.
Even the linked article just referrences an overview of the technology and it's goals. Why not an update... did they make a breakthrough? SOMETHING...
vs. Railroad Gun
Really?
Everything is better with chainsaws.
You can't put anything in orbit with any gun, acting by itself. You must apply some thrust after the projectile reaches the desired height. If you don't do that, no matter how powerful the gun is, no matter how high the muzzle velocity is, no matter where you point it, one of two things will happen: it will hit the earth before completing one orbit, or it will fly away and never come back.
If you want to launch to orbit from a gun, you have to provide a rocket motor on the projectile that starts up at the appropriate point in the trajectory.
Here's another way to express it: you cannot achieve a repeating orbit whose low point (perigee) is higher than the last point at which thrust was applied. For a simple gun, that point is the muzzle.
Technically that is not accurate.
You could (theoretically) fire a ballistic projectile at an escape velocity and at such an angle that the atmosphere will slow it down to be an orbital velocity. You could also fire and use a gravitational slingshot to put an object in orbit.
Thrust is not the only means of changing a ballistic trajectory into an orbit, both drag and gravity work as well.
The first point here also means you cannot really have a perfect ballistic trajectory inside an atmosphere.
Doing it from a ship or land based gun will give you problems because the Earth has this curvature, and your hypersonic dart is pretty much going to travel in a straight line. So things that are over the horizon are pretty much out of reach since drilling straight through the Earth is not really practical.
These projectiles will certainly be guided (http://www.popsci.com/technology/article/2012-08/its-experimental-rail-gun-navy-wants-gps-guided-hypersonic-projectiles) with accuracies at least as good as current ICBM systems, and probably as good as existing precision bombing systems like JDAM (http://en.wikipedia.org/wiki/Joint_Direct_Attack_Munition) and others. There are plenty of ways to guide a very fast munition that do not require sticking control surfaces out in a hypersonic air stream.