> During the Vietnam War, there was limited use of the Lazy Dog bomb, a steel projectile shaped like a conventional bomb but only about 1" long and 3/8" diameter. A piece of sheet metal was folded to make the fins and welded to the rear of the projectile. These were dumped from aircraft onto enemy troops and had the same effect as a machine gun fired vertically.[3][4] Observers visiting a battlefield after an attack said it looked like the ground had been 'tenderized' using a gigantic fork. Bodies had been penetrated longitudinally from shoulder to lower abdomen

That is utterly terrifying.

Adding to this: all war is utterly terrifying. People like to pretend it's not but it is. It's not "only" soldiers being killed in all crazy ways but other people being killed, raped, tortured, etc. Babies included like when the Japanese would throw them in the air and let them fall on their katanas. That's reason enough to avoid war.

Flechettes have been horrifying since WWI.

Orbital kinetic bombardment is a silly concept suitable only for cheap sci-fi novels. There's no benefit in having kinetic weapons permanently positioned in orbit. The satellites would be easily tracked and vulnerable to ASAT weapons. They can't strike a target much faster than a ballistic missile launched from land or sea. And they would be much more expensive. Anything in orbit is out of reach of maintenance. It takes a lot of energy to get a satellite into a stable orbit, and then yet more energy to de-orbit a missile.

I think you're forgetting a number of advantages.

1. Surprise. All land-based launch sites are actively monitored all the time, giving countries advance warning when a missile is launched. Submarine launches cut down this warning time, but still light up radar and thermal all over the place. A kinetic impactor falling from LEO can hit its target before the enemy even reports up the chain of command (we're talking single digit minutes).

2. Lack of radioactive fallout while still having larger destructive force than conventional munitions. If you need to destroy an entire air base far behind enemy lines, but don't want nearby population centers to be irradiated, you're looking at pretty bad options today, compared to a kinetic bombardment.

3. You can't really intercept a kinetic impactor. We have the technology right now to shoot small rockets right out of the sky, and at least a chance of intercepting ICBM payloads. With a kinetic rod, though, intercepting it wouldn't really do very much - it's just a big chunk of mass moving really fast. The best you could do is break it into smaller pieces that are still moving really fast.

No that's all wrong. Firing a missile from orbit has less surprise value than firing from a submarine because satellites can't hide. There's no difference in kinetic effects; a non-nuclear ballistic missile can hit just as hard at a lower cost (do the math). A kinetic projectile launched from a satellite is no harder to intercept than a ballistic missile in the terminal phase, and satellites themselves are highly vulnerable. A big chunk of mass landing near a target won't have much effect. And the projectiles couldn't be just rods. Due to the variability in rockets used for de-orbit burns as well as atmospheric conditions they would need fragile and sensitive guidance packages.

Kinetic impactors are not missiles. Repeat: Kinetic impactors are not missiles.

https://en.wikipedia.org/wiki/Kinetic_bombardment

These are not things that get fired. You don't launch them.

They don't follow a trajectory. They might just travel straight down from a geostationary orbit, depending on implementation. Yes, a guidance package might be necessary (depending on target discrimination, and precision, which in warfare isn't always required). They aren't gliding like smart bombs though.

At the speed of re-entry, and with possibly just 100 short miles to close, a defensive interceptor would be unwarned, have to acquire possibly many targets (one need not drop only one). Intercepting vehicles would have to close on a target in an arc representing a distance longer than the hypotenuse of the right triangle between the kinetic slug, the interceptor's launch site, and the defended target.

The slug is simply released with no indication of ingress. From a geostationary orbit, it just starts getting closer very fast. Cover it with EM absorbant, non-reflective material, and there's even less hint of activity, until the re-entry burn at approximately 60 miles altitude. Unless the target itself is equipped with interceptors, and lots of them, it will be difficult to notice and recognize in time, and even harder to catch and defeat.

> They don't follow a trajectory. They might just travel straight down from a geostationary orbit

That's not how orbiting works. If you want your projectile to travel straight down, you need to cancel all it's orbital velocity. For geostationary orbit, that's 3km/s of delta V needed.

Obviously, you can de-orbit with less delta-V, but then guidance starts becoming necessary.

> The slug is simply released with no indication of ingress. From a geostationary orbit, it just starts getting closer very fast. Cover it with EM absorbant, non-reflective material, and there's even less hint of activity, until the re-entry burn at approximately 60 miles altitude.

There is going to be some kind of burn to start de-orbit, you could simply monitor for that.

I am wondering, what kind of impact would the wind have on these projectiles? Or even on ballistic missiles?

I would imagine a nuke having such a large explosion that missing the target by a kilometre won't matter too much. But with a kinetic projectile that kind of deviation would not be acceptable (unless we are talking about seriously big projectiles, like in Tunguska etc).

Wind and other transient atmospheric conditions have a major effect. That's why individual unguided projectiles can't reliably hit a target more than about 4 miles away, and even at that range you have to be really lucky. The range from LEO to surface is a lot longer.

If you were going to use this as a first or second strike kinetic weapon platform (and prepared to tap dance around the "no militarization of space" treaties by claiming it's an aircraft), then your biggest asset is orbital velocity. It's sitting up there doing 7-8 km/s.

Obviously you don't want to do a powered de-orbit for reasons mentioned (you burn fuel & lose kinetic energy). However, if you're flying low enough, couldn't you aerobrake your projectiles after release and have them de-orbit themselves?

For comparison, the X-41/51 scramjet programs appear to be aiming at the mach 5-9 region. So less than 1/2 as fast.

As complicated as the materials science and guidance has to be for any X-71-based projectiles, slowing down and terminal guidance (ablative coatings and sacrificial control surfaces) seem like easier problems than boosting up to ridiculous velocities.

As for tracking, you get the heat bloom as it aerobrakes, but if you manage to keep it coherent through re-entry then the ridiculous speed largely moots that.

At 5 km/s, with a prograde orbit, you're from Istanbul to Beijing about 24 minutes (by my sleepy calculations?). The exercise seems more of a question of "How steep can you dive (aka how much heat can you handle)?" than anything else.

PS: Well, and "How the hell do you communicate-with / sense-from a platform surrounded by air that hot?"

Orbital velocity is no asset. In fact rather the opposite. You can't just start aerobraking. There isn't enough air in orbit for parachutes or wings to have any noticable effect. The only practical way to get out of orbit using current technology is to conduct a de-orbit burn with chemical rockets.

Of course that's all pointless because a ballistic missile launched from Earth could accomplish the same mission at a far lower cost with greater reliability and survivability.

You absolutely can just start aerobraking if you have maneuverability on the launch vehicle (because it's small, packed with fuel, and limited duration).

Regardless of what orbit you start from, you dip into the atmosphere, deploy your payload from there, voila.

Now anything you dropped has to deal with a furnace of superheated air, and the question of whether it's possible to have control in those conditions, but it's definitely going to de-orbit.

And the atmosphere is going to supply most of the energy, rather than direct retro burns from the delivery vehicle.

This is 100% wrong. You don't understand orbital mechanics. Everything follows a trajectory until force is applied. When you release something in orbit it doesn't fall down. It continues orbiting until an attached rocket motor does a de-orbit burn. Rocket motors are subject to manufacturing variations plus there are a lot of atmospheric effects on the way down to the surface so any missile would require a sophisticated guidance system to have any chance of striking a target.

Prove to me that a rocket simply MUST be burnt, to set an orbiting mass in motion.

Propellant is a conventional means, but certainly not the sole means. Magnetic induction could eject a slug from an orbiting platform, or inert gases could jettison to induce motion. Burnt fuel isn't a requirement.

You insist on a rocket motor. But you just resist the idea of this form of orbital weaponry.

A large enough asteroid could enter into earth's gravity well and chart a straight line to impact.

You presume preconceived concept of a weapons platform already in orbit, controlled from the ground, or by a terrestrial entity. But a weapon of lunar origin might insert into the atmosphere differently. As with any weapon, an approach to target should be the least defensible path. After atmospheric re-entry, when position is given away, you'd want the penetrator to travel as perpendicularly to the target as possible, but prior to that moment, any stealthy approach is game.

I'm not 100% wrong. You're 100% obstinate.

You are still 100% wrong. Magnetic induction wouldn't be be practical because it would disrupt the satellite's orbit. Inert gasses are too heavy to be practical for the amount of delta V needed. You're just making things up and missing basic physics concepts.

You're imposing constraints where there are none, and declaring physical law as an insurmountable barrier, because you are sourcing all materials involved as terrestrial in origin, and insisting on reusability.

Magnetic induction would also apply opposing forces to the launch satellite, but that doesn't matter if the launch satellite is just as disposable as the slugs that destroy the target.

Inert gases are too heavy, only if the weapons program tries to collect them on the ground and launch them into orbit.

I'm obviously making things up, because this is a system open to invention, given that it doesn't actually exist yet. This concept is less practical, if you operate within existing constraints, using only rocket propellant to boost objects into orbit, and then subsequently de-orbit them.

Game changers emerge, when new ways of operating in space appear. Even if this is "less practical" right now, after the introduction of adjacent technologies, as an existing concept it could suddenly become practical. For example, with the introduction of a space elevator, boosting such a weapons system into orbit is less costly. Then, more of its components become readily disposal at practical values.

I'm not required to operate within existing economic constraints, to consider ideas that are not actually limited by physical laws.

>They don't follow a trajectory. They might just travel straight down from a geostationary orbit

So you're just going to target the equator then?

It's gotten a pass for too long.

Assuming everyone lives, builds stuff, and maintains stuff at the bottom of the gravity well is an assumption well suited to the present day, but not to the setting of most cheap sci-fi novels.

The main problem is that even 500kg at sub-7 km/s doesn't deliver that much energy. Conventional weapon of the same mass is way more effective (and this is why ICBMs now can deliver conventional warheads).

Look at the payload capacity of the X37 it would do about as much damage as a bunker buster.

If the X37 is public they probably have something bigger and better tucked away in a hanger somewhere remote. Think about how long the F-117, SR-71, U-2, B-2, or RQ-170 were kept secret. There is no way they haven't thought about how to use this in a military capacity.

If they do, it's almost certainly never been put into orbit. The guys who track satellites as a hobby are good.

For sure. I've read that the RQ-170 was seen quite quickly by plane spotters - likewise with the planes used for extraordinary rendition.

Never underestimate passionate nerds and their ability to notice unusual things!

"Rods from God" - spent way too much time on Friday on Wikipedia reading about these, and other Kinetic concepts.

People always talk about kinetic strikes in the context of big flashy things like rockets and spaceplanes. I'd be a lot more worried about them being dropped from stratospheric balloons - maybe not so useful for full scale bunker busting but extremely cheap to make and almost indefensible against as a strategic strike system.

This reminds me of a novel weapon from the Daemon novels. Basically, small semi-guided darts dropped from weather balloons that were used as antipersonnel weapons rather than as a replacement for conventional explosives.

https://en.m.wikipedia.org/wiki/Flechette and https://en.m.wikipedia.org/wiki/Lazy_Dog_(bomb)

Something similar has already been used here since​ WW1.

Err, shoot the balloons?

The ressources required to shoot stuff that's in the stratosphere are on a whole other ballpark than what your average revolutionaries can do.

Industrial-strength laser is all you'd need...

Intercepting stratospheric balloons is child's play, possibly literally, compared to intercepting chunks of metal flying at 10km/s, which are the alternatives under discussion.

> I'd be a lot more worried about them being dropped from stratospheric balloons - maybe not so useful for full scale bunker busting but extremely cheap to make and almost indefensible against as a strategic strike system.

If you meant to speak from the point of view of a revolutionary (why?) and note that stratospheric balloons would be a cheaper way of killing revolutionaries than ICBMs or Rods from God, sure, I agree. There are a million ways to shoot fish in a barrel. Forgive me for assuming your point-of-view party was militarily capable.

The Soviet Union spent 40+ years, and many pilots' lives, trying to devise a means of destroying CIA balloons operating at 30km altitude. SAMs, AAMs, artillery and even ramming all mostly failed.

Eventually by the late 1980s they developed the Myasishchev M-17 balloon interceptor aircraft, with a dorsal cannon-turret and able to loiter for hours at 22km. Still not quite sufficient.

Now increase the balloon altitude to 50km and they should be safe against any opposing force with early-2000s levels of military capability.

60+ km straight up is a long way to shoot.

Even satellites can be shot down:

https://en.m.wikipedia.org/wiki/Anti-satellite_weapon

cool idea but I'm gonna assume its a lot more expensive to send up an X-37 and have it crash back down then it is too just send a few nukes at your target.

If you look at it purely from a costs perspective, maybe.

Don't discount the PR disaster that would ensue from the US using nukes in any scenario other than retaliation for a nuclear attack. Nukes used in anger would likely mean worldwide condemnation, sanctions, and pissed allies complaining about fallout.

Preface: I don't think this is a likely explanation.

But if you think it is, there's a big advantage of kinetic weapons over ICBMs, namely that they are a lot more credible as a first strike weapon. ICBMs launches are quite detectable, allowing counter strikes (hi there nuclear deterrence).