Navy Railgun Tests Leading to Ship Superweapon by 2020

Dannyalcatraz · Mar 4, 2012

A rail-gun should be able to minimize it.

It does, but even so, you can see a good 6" of recoil (on something anchored to the Earth) in the demo video. That may not sound like much, but for a space-based weapons platform- the context in which we were discussing recoil- that is quite significant, both from a targeting and maintaining orbit standpoint.

Yes, such a weapon would doubtlessly be smaller than that thing, but even so, it's a factor that needs to be taken into consideration.

El Mahdi · Mar 4, 2012

TanisFrey said:
Earlier, several of you were talking about recoil. A rail-gun should be able to minimize it. In a traditional gun/cannon/rocket launcher the ammo rests upon the barrel. When it is fired it must over static and dynamic friction of the barrel/rocket tube and the air in the way. The first thing a rail gun does in preparing to fire is to generating magnetic field. This will suspend the round in the middle of the chamber and not touch the "barrel wall" at all. This will eliminate the need for extra force needed to over come it. This is why they are talking much longer ranges then a gun powered system.

You're forgetting that the projectile also has a magnetic field. It's the opposing magnetic fields between the projectile and the rails that propel the projectile. The magnetic field generated by the rails is essentially "fixed" to the barrel. The force generated by the two fields both push the projectile out (at an extreme velocity) and also push the weapon back (recoil).

Recoil is very much a consideration. The larger the projectile (such as a larger guided projectile vs. a simple slug) the more recoil there is.

B-)

jonesy · Mar 4, 2012

What would happen if you placed two of those railguns in space fixed together so that they were firing opposite of each other? Would they just break apart, or could one build a space bazooka (with a "backblast" that was exactly as lethal as the other direction)?

Dannyalcatraz · Mar 4, 2012

You could, but that just makes targeting more complex- imagine having a target in your forward gunsights just as one of NOAA's satellites goes into range on the second one!

Umbran · Mar 5, 2012

TanisFrey said:
In a traditional gun/cannon/rocket launcher the ammo rests upon the barrel. When it is fired it must over static and dynamic friction of the barrel/rocket tube and the air in the way. The first thing a rail gun does in preparing to fire is to generating magnetic field. This will suspend the round in the middle of the chamber and not touch the "barrel wall" at all. This will eliminate the need for extra force needed to over come it. This is why they are talking much longer ranges then a gun powered system.

No, on several counts.

The railgun round has longer range because (as I noted upthread) it leaves the barrel moving faster than the conventional round (up to three times faster, by the article). The range is directly proportional to muzzle velocity.

The force required to overcome friction in the barrel should be small compared to the force required to get the round up to that speed in such a short distance.

If we have one rail gun that tosses out a missile so that the rocket engine fires in midair. We can eliminate the occasional dangerous misfire and extend the range of the missile in question.

That's a boazooka as a flyswatter. You can toss the missile overboard with far more conventional means.

jonesy · Mar 5, 2012

Umbran said:
That's a boazooka as a flyswatter.

Boazooka. Indiana Jones's nemesis.

Umbran · Mar 5, 2012

Dannyalcatraz said:
You could, but that just makes targeting more complex- imagine having a target in your forward gunsights just as one of NOAA's satellites goes into range on the second one!

""Space is big. Really big. You just won't believe how vastly, hugely, mindbogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space, listen..." --The Hitchhiker's Guide to the Galaxy.

This isn't like a firefight on the ground, you know, and despite what Hollywood shows us in Star Wars dogfights, targets in orbital combat are few and far between. The likelihood that there's another target in that tiny volume of space behind you is very small.

Firing backwards would solve much of the recoil issue. However, it will take twice the energy and power, ammo, and cooling capacity to do it.

Really, the recoil issue would be that, out in space, you're taking your shots not from a mile, or tens of miles, but hundreds or thousands of miles away - over those ranges, your targeting needs to be perfect, and to do it you need to know the relative positions, speeds (and possibly spin) of both the gun and the target. Recoil means those positions, speeds, and spin may change with every shot you take.

Kzach · Mar 5, 2012

Could you propel a form of energy using a rail-gun?

jonesy · Mar 5, 2012

Kzach said:
Could you propel a form of energy using a rail-gun?

That's what it already does. It transforms other types of energy (depending on the power source electric, electromagnetic, nuclear, chemical etc.) to launch projectiles with massive amounts of kinetic energy.

Dannyalcatraz · Mar 5, 2012

Umbran said:
""Space is big. Really big. You just won't believe how vastly, hugely, mindbogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space, listen..." --The Hitchhiker's Guide to the Galaxy.

This isn't like a firefight on the ground, you know, and despite what Hollywood shows us in Star Wars dogfights, targets in orbital combat are few and far between. The likelihood that there's another target in that tiny volume of space behind you is very small.

I agree, but more and more scientists and governments are discussing how crowded- "crowded" being a relative term, of course- with satellites AND debris some orbits are becoming.

Besides, even if the odds are vanishingly small, how'd you like to be the lucky officer who won the "I just shot an expensive satellite with my backblast" lottery? ESPECIALLY if the unintended target belonged to a hostile nation? I wouldn't even want to be the signatory on the document that greenlighted such a design.

(Your other points about wasting ammo, energy and so forth are 100% valid, though.)