Star Wars

i know that a program such as SDI (space defense initiative) has been a controversial issue over for over 20 years from whence it was first conceived.

SDI is concidered to expensive to even conceive imagiable, but my idea is what if you place say a fleet of lets say seven satellites in geostationary orbit over the country concidered hostile, the first 2 satellites cosist of ground targeting anit-missile destroyers whos primary aim is to shoot down, from space, atomic missiles that travel at near ground levels. The second 2 satellites could target ICBMs that enter space, destroying the whilst in space. Finally the last three satellites could be used to track and locate hostile targets, co ordinating the rest of the satellite fleet.

what role would the commercialization of space play in protecting countries from nuclear threatsand the militariztion of space?

Sounds rather like using a scatter gun in hostage situation. A missed shot at an ICBM from Geo would be a major hazard to the ground below, which might not be on hostile territory. Also, the killer satellite would be a hazard to the nearby comm satellites as the geo orbit is very crowded these days. Any nation capable of producing high-energy lasers and quality optics could take the satellite out too, geosynch satellites tend to be easily tracked.

Although it certainly would be a hazard to any satellites it was pointed at (although that is one of the primary reasons for placing it in orbit), a high-power LASER is actually little threat to targets on the ground, for a simple reason: they don't miss. You test, retest, and rererererererereretest the controlling software. Diffraction and refraction (although there's little enough of that) have to be taken into account, of course, but that's what the software's for. Then all you do is point it at a missile, hit the little red button, and laugh. Because you don't have to lead the target by any measureable amount, you don't have to deal with anything more than the most basic atmospheric conditions (if it's raining and the wind's from X degrees at Y miles per hour, adjust aiming accordingly), and you don't have any real difference between the time of firing and the time that the beam hits the target, it is surprisingly hard to miss with a LASER.

Also, remember that destroying ground targets with impunity and taking out enemy communications and weather satellites is one of the biggest things in favor of an SDI system.

Oh, by the way, you pretty much need a full power plant to yourself to power a reliable surface-to-orbit LASER.

Oh yeah. Just point and shoot, simple as that. Never mind the distance is over 35.000 kilometers, the target travels at several kilometers per second and is smaller than an average sedan; putting the odds in favor of photographing a bullet across a soccer field. And by the way, there's never anything 100% safe no matter how much you test and re-test it.

Military aspects of space are the origins of space exploration of the past. The future will be more concerned with commercialisation. Commerce has greater power today than ever before in the past. I'm still a little uncomfortable deploying weoponry in orbit. There is so much junk and debris up there, that a small mishap with a nuke power plant or missle system could cause untold damage. Nope, I'd rather leave that for Sci-Fi for now. Let's colonise, then we can let the fanatics blow the *** out of themselves.

Noble sentaments, but the history of our planet does not encourage me to hope for a weapons free space. I suspect we will need to make sure we have the best and the first, just as we do in conventional forces.

But that very attitude accelerates the problem. If nobody takes weoponry up there, then nobody else would need to follow suit. You just watch, imagine China or Europe put a weopons platform up there. Doesn't matter who first does it, everyone else with a similar capability will feel the pressure to do the same, just to keep the balance. But what destabalised the balance in the first place was the deployment of the first system.

Space based defence assumes that you're fighting a similarly technological advanced enemy. I'm not sure that a space based defence system could defend against a chemical or biological attacks. Yet these happen to be todays greatest threat (and shooting one of them down, just drops it's payload a little earlier than intended). Nukes while powerfully dangerous, continue to be simply too dangerous to actually use against a target that might retaliate in kind. So they're not what we're defending against. Nope, it's the fanatics with a grudge that are the deadly ones, and something in orbit is unlikely to stop them. Unless we're talking about spy sats.

My dear friend, that is what is called an idealist's solution. Space-based weaponry is assured. It will likely be started as strictly defensive, then accelerate into offensive weaponry. Think: if you're going out of the Earth-Moon subsystem, you might want a small laser system to take care of any meteorites that get too close for comfort. It's only sensible. However, the development of these systems and mining systems will eventually be applied to offensive and defensive weaponry.

Vendigo: You're a bit off in your calculations. Suborbital altitude is 68mi; say a nice HEO is 750mi. Light travels at 186,273 miles/second. This means that, from the instant that the fire command is sent, it will take precisely 0.0080526968 seconds for the beam to hit the target. That's 8 thousandths of a second. As I said, there is practically no target movement. So yes, it is as simple as point and shoot. Also keep in mind that a laser beam -- even from orbit -- can be kept to as small an effective diameter as you like, although a 1-foot diameter is about the limit (might be a bit more than that; I'm not quite sure). No argument that there is never anything 100% safe. But the chances of it missing a target can quite easily be reduced by sufficient testing to less than the odds of you winning the lottery -- twice.

yea, with lightspeed weapons at *relatively* close ranges speed is no factor, only when you get out to .1 light second or so that it starts even being a minor issue.

The said orbit was not HEO; it was GEO. Don't try to impress me with the numbers, I _do_ happen to own a calculator. Even in HEO it's not going to be just "point and shoot". It's one thing to detect a warhead in space, intercepting it is entirely different matter. It's still like catching bullets in flight. You need to be PIN-POINT accurate with laser. Detecting, pinpointing, aligning and firing is a lot of work for any unscheduled orbital encounter. A warhead does not have a large RCS; the radar would need to be immensely powerful to detect it in time. It looked nice and pretty in those SDI videos, but don't get fooled, it's NOT going to work out that easily. As for the satellite laser weapon, the only source of energy powerful enough is a NUKE.

I never said it'd be easy, just possible. Of course fire-control's a bitch: but then again it's not easy for a Phoenix missile or a Phalanx cannon either. And as for energy sources, where better to place a fission reactor than in orbit where it can't harm anything -- and it also provides a nice last-ditch weapon: if all else fails, crash the satellite into a predetermined target. Crude, but effective.

How many ICBM's can you shoot down at once?

The counter to SDI is to stealth ones missiles and make a lot more of them.

In fact, sponsor an X Prize team to make cheap sub orbital missles with a radar profile the same as an ICBM... then launch them all at once. No SDI system imagined could take down that many missiles, and if your ratios are ten dumies to one real nuke then its likely that you won't even shoot down a single real nuke.

completely false. a good geosynchronos laser could shoot gods know how many times per minute (machine gun speed at least) and each one with nigh perfect accuracy, it could probably stop oh, say, 500-1000 missiles if they were detected as soon as they launched, maybe more. after all, at that range you don't exactly have to move your aim much.

EDIT: oh yea i forgot to mention that since we have no military lasers and no software to aim a laser, i'd put the minimum time envelope of making a *good* GEO laser at 20 years at least, and good does not mean perfect: your laser is only as good as your software.

Is this thread supposed to be a joke? 500 to 1000 is so ridiculously absurd figure I can't reallly comment on it. I suggest considering how HOT the laser would get in action.

Another thing; let's assume the target is is ten feet in diameter (to the benefit of the pro side). At geo, the allowable circular error would be about 0.43 microradians, or same as hitting a this mark here --> * <-- a mile away. Sure, you don't need to move your aim QUICKLY, but you do need to move it ACCURATELY. By the way, it takes over 0,1 seconds for a laser pulse to reach LEO from GEO, at which time the target can move, say, quarter of a mile. "point and shoot"? No way.


Furthermore, this thread is very off-topic for the forum. For one, it suggests unilateral control of space. Second, it portrays the very antithesis of X-prize ideals. Third, it's miserably bad science.

Yeah, next we'll be intercepting targets, and teleporting them out of danger.
Which curiously is exactly what some of our big thinkers are working on. But that's a long way off.

If we have to have space based weapons, then I'd assume that they might take the form of small bullets accelerated using a rail gun to enormous velocities, aimed to intercept a target.

This is a bit depressing though isn't it? I'd rather be thinking of exploration and exciting times, rather than war and aggression.