But then, if the railgun was shot at close range, this would be true for the firing ship as well...
Yes, I have wondered when throwing around nukes and high energy shells if a 'minimum safe distance' isn't something you would want to look at. And having your own nuke chase down a ship closing on you could also turn out embarassingly.
(I am so looking forward to dealing with this. I do hope it works out.)
I have said more than enough on what I feel will happen if you shoot a ship. On the heat of the slug, when you compress mass it heats also, and it occured to me some time back (shortly after composing the thought that slugs probably look like cannonballs) that it is probably going to be molten when it leaves the railgun, or shortly there after. If not molten, at least fairly close (depending on the material). As I said, I would want a material that best deposited all of the energy into the target.
On the speed of expansion, this is one that I have argued with colleuges before. The current formulas for shockwave propagation are less than ideal. The don't always confirm experimental observation, so it truly is open to debate in some areas. The rate that a wave can propagate through material can actually exceed the speed of light in certain mediums (which is why reactors glow, the electrons are exceeding the speed of light in water). With the levels of energy and velocities we are talking about, we could get a large number of people arguing, but all should agree it would be fairly energetic.
Whatever is easiest for Steve, is fine with me.
I'm a tiny bit skeptical about this. No offense, but anyone can say anything on the internet, and I find it hard to believe that a couple kilograms of copper is some sort of wonder penetrator.
As for penetration, there's a professor at my school who studies armor penetration and space debris. I'm meeting him on the 26th, and will try to get some answers.
I tend to be skeptical by nature also, so this is not a problem for me. Do all the research you want. I can only talk from what I have seen and worked on. I don't know how much data is available on some of the EFPs from the IEDs in Iraq, as the military was pretty good on confiscating any cameras or notes that were on the soldiers around if it involved penetration of the armor on an M1. But data on the APDS penetrators the M1 (ok, most any NATO 120mm smoothbore) fires is fairly easy to get ahold of. It would do just as well as an example of what happens to a chunk of material striking armor at a few km/s. Turns molten as it punches through and then 'detonates'. Easier to find and just as much a proof of concept.
EDIT
The example with copper was just to show that even a material that common can make a good kinetic kill penetrator. (Actually, it is looking to become the material of choice in some EFPs).
You will likely be able to set a dispersion rate for the latter (I am assuming a small explosive charge to provide 'sideways' momentum), so while the forward motion of the projectiles will be the same as the original missile, the rate at which the 'width' of the projectile cloud increases over time will be preset during missile design. Obviously the speed at which the 'width' increases will be far less than the forward momentum.
Steve
You really don't need an explosive charge, and could control the dispertion rate fairly accurately with modern tech. Just have the 'shrapnel' be 'sleeves' of cylinder like slugs. Then have the missile begin to 'spin' as it releases the slugs. It would be able to control the dispertion and density without the random accelerations of an explosive. When done you could have a small explosive charge (a bit of left over propellent) shatter the remaining hull of the missile to add extra fragments to the center of the pattern.
If you had a ship nearby that could communicate with the missile, controlling the rate of dispertion might not be difficult 'on the fly'. (Ok, sorry about the pun...)
If the missile was still accel/decel ' ing while releasing the slugs it could even create a 'cloud' with considerable length as well as width, in case you are intercepting a crossing target and having 'ordinance' in the target's flight path for a duration of time was important.
But this isn't a big issue for me. You do this for free. Whatever suits your fancy will work.
As long as I get to try and blow up the 'bad guy' !!