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Comment by vl | Hacker News Reader

Lets get bunch of rails into the low polar orbit. Once a 1000 or so is deployed, there will be an almost-instant (20 minutes) strike capability for any location on the earth. The good part is that kinetic energy of re-entering rail will be unmatched by any railgun.

On the serious note, they didn't specify the weight of the projectile, and this is quite important factor. Comparison of the energy delivered at the target range to the energy delivered by the conventional winged missile would be useful as well.

Blog of the guy who build portable supersonic railgun at home (in Russian): http://railgun.org.ua/ Check out his video page: http://railgun.org.ua/video/

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You already have 20-30 minute strike capability for any location in world. You've had it for decades.

What you want is 20 minute strike with less warning than existing ICBMs. And also banned. The nuclear weapons reduction and restriction of weaponization of space treaties are some of the successful treaties with regard to controlling weapons that anyone, let alone the United States has been involved with. Violating said treaty will bring ridicule and anger to whoever breaks it, and a non-miniscule chance of the other major nuclear powers launching all their nukes.

As much as I would prefer otherwise, it seems pretty clear that space has already been weaponized. Between the Shuttle the X-37, and whatever else exists, for all we know there are already satellites in orbit armed with kinetic kill vehicles.

All satellites in orbit are already kinetic kill vehicles, just with varying degrees of sophistication. Everything in space is a kinetic kill vehicle. The idea that space can somehow not be weaponized is sheer physics ignorance. In some ways this is the largest challenge to space exploitation, which is rapidly becoming relevant as commercial spaceflight recently passed a milestone. A corporation that can retrieve an asteroid for mining purposes is a corporation that can drop that asteroid on your capital. There aren't very many realistic treatments of this scenario in "the literature". ("The Moon is a Harsh Mistress", at least the base scenario if not the details of the superintelligent computer, is one of the few.)

Maybe I shouldn't have used that term. I am aware of the basic physics of the situation, but that's not what I was talking about. I think it's likely there are already devices in orbit with the capability of launching "dumb" (i.e., non-explosive ) munitions to either take out other satellites or small targets on earth.

When people discuss the weaponization of space in terms of the treaties, implying ignorance because it isn't about basic physics doesn't provide any constructive input, and is frankly just needlessly hostile. These treaties are about weapons in a military sense, with the ultimate issue being the presence of nuclear weapons in orbit. I don't think it would be news to anyone that the whole business is inherently dangerous and that anything in orbit can come down anywhere on earth with little warning.

But that's the point. Anything nontrivial in space already is a military weapon. (Though most satellites are trivial by this measure, I'm really talking about the mid-term future.) It doesn't even have to be nuclear. It is not possible to really seriously use space without it being intrinsically weaponized. There's no such thing as non-weaponized space.

And no, I seriously doubt our political leadership really understands this at a gut level. You might even find some people in such positions that could pay lip service to the idea, but still don't really get it. You don't even need "nukes", which, frankly, are redundant pretty quickly and would only add a psychological scare factor.

I am absolutely with you in thinking that politicians don't get this at all. My main point is that there is a context in which those terms are used that doesn't immediately mean that anyone who uses them doesn't realize that mass in space == potential big boom somewhere.

>...for all we know there are already satellites in orbit armed with kinetic kill vehicles.

That seems more like pure conjecture than anything clear.

I do remember a PopSci article talking about doing it, but no one would dare admit it if they did.

By "strike capability" here I mean "small payload pin-point strike capability", not "nuclear warhead". But you are correct in that it's possible to use ICBM to deliver rail to the target.

How would you use ICBM to deliver rail?

By "rail" here I mean long prolonged heavy metallic object. Replace warhead with the rail and launch ICBM.

No, we need something cheaper.

ICBMs are too expensive to use to deliver conventional explosives or kinetic kill projectiles. Forget bioweapons and toxins, they're not any deadlier than cluster bombs.

The power of an explosion follows an inverse square law, so you can destroy something with 1/4 the explosive if you can get twice as close to it.

If you could drop thousands of 25 lb bomb equivalent devices an hour with GPS accuracy at a city, you could wreck it's infrastructure in a few weeks.

And wish nuclear death on yourself. You also already are developing that ability with Prompt Global Strike (essentially non-nuclear ICBMs).

I believe prompt global strike (and similar schemes) to be highly unstabalizing and to be avoided at all costs. The global suspicion (with a country with 2000k+ nukes none the less) would be suffocating. If the USA employed such a system, the moment you acted as anything less than a white knight, the world be up in arms. And justly. Your friends (the UK and Canada and Australia) would start edging away. And then you're truly fucked. (Canadian).

Reality check:

According to that logic, Canada should already have that attitude to the US, since most of their population is inside aircraft range...

Huh, why the minus votes? Is there anything wrong with the argument or is this political believers' reactions?

Airplanes [edit: and rocket artilleri, for that matter] in range is functionally the same thing as such a strike capacity, but cheaper.

There is no reaction from Canada and won't be; see the democratic peace theory.

If you take the numbers from the article as accurate, 33 megejoules at Mach 7 means the weight is ~15kg (assuming I got all my conversions and orders of magnitude right, feel free to do your own e=1/2mv^2 calculation...)

I got ~10kg from the 2500m/s number, and under 12kg from the Mach 7 number. Google agrees:

http://www.google.com/search?q=2*33megajoules/(2500+m/s)^2+i...

http://www.google.com/search?q=2*33megajoules/(7+*+speed+of+...

Projectile speed will be much less after it has travelled 100km.

Yea except that inconvenient treaty that states you can't put weapons in space. Oh and also if you try to do this China would just try to shoot it down anyways. http://en.wikipedia.org/wiki/Outer_Space_Treaty

I don't think other world powers would be totally cool with us putting superweapons into low polar orbit right over their heads... you should totally expect those satellites to be shot down as soon as you put them up there.

Why would they shoot down relatively harmless rails from the orbit and not other already existing spy satellites?

because of offensive vs. defensive purpose?

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