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Planetary Invasion/Defense 
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Post Re: Planetary Invasion/Defense
Yeah... that hiding only works if you are NOT using total WAR tactics. If you are concerned about indigenous inhabitants! The U.S. military could have killed every damn thing in the area if they would have been allowed to use every nasty and insidious weapon in our arsenal to kill anything living crawling or otherwise in those mountains.. but public opinion would not have supported such excessive - but damned effective force!

Things get even more "pear-shaped" if you add nuclear bombardment, chemical carpet bombing or even biological weapons... not even including hunter killer robotic autonomous inorganic weapons.

EDIT: LOL... H.A.I.K.U. [Hunter Autonomous Inorganic Kill Units]

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Last edited by sunphoenix on Thu Mar 24, 2011 11:18 am, edited 1 time in total.



Thu Mar 24, 2011 10:44 am
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Post Re: Planetary Invasion/Defense
Alright. Let's clear something up. Orbital bombardment is not an option for the Logieri. For them, the planet represents many decades and trillions spent on infrastructure development. The Logieri are not (at least at first) willing to destroy decades of effort development over what they believe is a minor border skirmish.

Second, food and ammo are not an immediate problem for the humans. The humans were originally invading and they expected a months-long ground siege for the major cities on the surface. They have sufficient stockpiles of food and ammo, even if their vehicle stockpile is better-suited for an offensive siege. When faced with such a massive ground force, the Logieri surrendered almost immediately, which was an unexpected, but smart move on their part. On the human side, public support for the war would evaporate immediately if the humans just started attacking a civilian population that has already declared a surrender.

And now a note on communications. For most species in the setting (including Humans and Logieri), the fastest form of interstellar communication is starships carrying messages. Essentially, this means that it's somewhat difficult to stay ahead of fleet movements.


Thu Mar 24, 2011 11:00 am
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Post Re: Planetary Invasion/Defense
I read again the first message.

Humans have selected few high valued targets, like capital city, religious leaders, nuclear reactors, traffik control centers, etc and take them for hostages.
Then they hide in cities and use population on their shields.

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Thu Mar 24, 2011 11:15 am
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Post Re: Planetary Invasion/Defense
Martenzo wrote:
Alright. Let's clear something up. Orbital bombardment is not an option for the Logieri. For them, the planet represents many decades and trillions spent on infrastructure development. The Logieri are not (at least at first) willing to destroy decades of effort development over what they believe is a minor border skirmish.


That only prevents them from using large scale strikes against humans in locations with valuable infrastructure. Unless they've developed the entire surface of the planet or concentrated everything of importance in a single point, humans moving from place to place will be exposed and can be taken out with minimal collateral damage. And orbital bombardment doesn't necessarily mean dropping asteroids to obliterate continents, they could very well involve precision strikes to take out individual tanks in urban environments.

Concentrations of force almost anywhere could be taken out with little overall collateral damage. A dispersed force is safe from orbital bombardment but far more vulnerable to ground forces. An attempt to respond to a threat from that involves concentrating force...

They could pick a city and abandon most of their vehicles, using infantry forces concentrated in a variety of high-value locations to hold the city. They'd have to pick their locations and spread their forces carefully...taking out a few buildings the humans are using as headquarters and living quarters could still break the human occupation without much loss. Large dams, manufacturing facilities, power plants, etc. Threatening to destroy infrastructure might make them less willing to provoke the humans, but would just make the situation with the locals even worse...and those in orbit have similar threats they can make: blow up a power plant, and we take out your headquarters, even if it takes out another power plant.


Thu Mar 24, 2011 3:21 pm
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Post Re: Planetary Invasion/Defense
For precise strikes, guided missiles are needed. Matter dropping will scatter on radius of miles and interference will eat power from any energy weapons.
The fleet is easy to detect from planet surface and when missiles are launched, the need good amount of time to travel & find the targets, so alarm is given.
Humans have couple of minutes to go inside of buildings or under bridges and shoot some anti-missile-missiles.

If Logieri wants to hit humans from orbit with minimal collateral damage, they need drop stealth missiles under horizon and have a some smaller reconno... scouting vehicles/soldiers to mark acceptable targets.

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Thu Mar 24, 2011 4:17 pm
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Post Re: Planetary Invasion/Defense
Nah. Not really. Laser guided, unpowered, fin-stabilized, 1ton steel I-Beams with perhaps a sub-munition kinetic-kill triggered warhead {if your just feeling mean} would work just fine and not leave much warning of its incoming threat... especially if you drop like a couple hundred of them! :)

Also remember... heh... rocks are even cheaper! :)

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Thu Mar 24, 2011 5:42 pm
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Post Re: Planetary Invasion/Defense
I think the Humans are just screwed.

Unless you give the Humans Huge jump in Stealth tech where the Logieri can't find them All the Logieri have to do is load up a Virus that kills humans and bam end game for the humans little loss for the Logieri.

Maybe the Planet is Sacred to more than just the Logieri?
That would keep the humans and the Logieri from trashing the planet and the cities.

Maybe another idea that the Logieri on the planet are a sect that is devoted to peace or something?


Thu Mar 24, 2011 6:08 pm
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Post Re: Planetary Invasion/Defense
bunnyboy wrote:
For precise strikes, guided missiles are needed. Matter dropping will scatter on radius of miles and interference will eat power from any energy weapons.


And why can't you bombard with guided projectiles from orbit?

Also, particle beams would not fare well in atmosphere, but laser weapons that are effective at space combat ranges will most likely still be somewhat effective against ground vehicles, and definitely against personnel in the open.


bunnyboy wrote:
The fleet is easy to detect from planet surface and when missiles are launched, the need good amount of time to travel & find the targets, so alarm is given.
Humans have couple of minutes to go inside of buildings or under bridges and shoot some anti-missile-missiles.

If Logieri wants to hit humans from orbit with minimal collateral damage, they need drop stealth missiles under horizon and have a some smaller reconno... scouting vehicles/soldiers to mark acceptable targets.


There's no way you're stealthing an object entering atmosphere at near-orbital velocities. However, interceptor missiles are a lot more complex (thus more expensive) than unpowered guided kinetic projectiles, and if your vehicles can't venture beyond a quick dash of non-expendible cover, the bombardment's effective without ever having to actually hit one. Plus the attacker's projectiles can be under the cover of the attacking ship's point defense systems for much of the trip.


Thu Mar 24, 2011 6:26 pm
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Post Re: Planetary Invasion/Defense
You can throw down from orbit whatever you wan't, but on atmospheric entry, friction will throw them slightly of from course, maybe couple to thousands of yards. Any guiding or transmission systems don't work because of heat, until the speed is sloved down. And the time for this is counted in minutes.

Lasers have problems in atmosphere. Energy around 1 megajoule in cubic centimeter will turn air to plasma, which cause to laser defocus and disperse energy. And any clouds or pollution makes it worse, because they absorb and scatter the light. And when the laser hit the target, evaporated material will cloud and shield the target.

You are right of about that, entry is impossible to stealth. But doing it out of horizon (visible/monitored area) gives it change to come unnoticed.

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Thu Mar 24, 2011 11:43 pm
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Post Re: Planetary Invasion/Defense
bunnyboy wrote:
Any guiding or transmission systems don't work because of heat, until the speed is sloved down.

Back in the mid-60's we had guided missiles that could accelerate at 400g and reach top speeds in excess of Mach 10, and were accurate enough to intercept aerial targets. The total flight time was measured in seconds. I don't buy that starfaring technology can't create effective guided orbital-drop missiles that are as accurate as today's JDAM's.

Very high frequency lasers shouldn't have any trouble penetrating atmosphere. These might have to be specialized for orbital strike (and perhaps not very useful in space-to-space application), but I would expect them to be very effective.

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Post Re: Planetary Invasion/Defense
Also it's not hard to acquire a chunk of matter large enough that you could sling it at a planet and cause damage over a huge area. Aiming is less important in that case, so you don't *need* to make anything fancy like a guided projectile, just calculate the trajectory and have your projectile have enough inertia and speed to get close enough. If you care about collateral damage I'd bet on lasers being your best bet.
-O


Fri Mar 25, 2011 12:40 am
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Post Re: Planetary Invasion/Defense
Not sure, but seems to be that spaceshuttles have a entry speed of Mach 24.
In that speed, the bomb can reach target in 15 seconds from 100 kilometres.
ISS is in 350 km away from earth, where it travel around world in 91 minutes, but because atmospheric conditions it is still falling 2 km per month.

The space fleet can't be stationary, unless having altitude somewhere 36 000 km! That means they aren't constantly present, which gives humans windows to operate.

And for collateral damage. Think that there are terrorists hiding in your home city. Do you have enough trust that collateral damage of effective "chirurcical" bombing is acceptable?

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Fri Mar 25, 2011 12:49 am
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Post Re: Planetary Invasion/Defense
bunny: well on the subject of hiding, hiding one man(or even a few hundred of them) with support of the local populace is one thing and quite doable, hiding something like a hundred thousand including hundreds of tanks and aircraft WITHOUT local support? forget it, not possible.....well, unless you bring magic klingon cloaking devices into the equation.
and with the kind of firepower available to military space craft, if you can see it, predict it's movements well enough for the ranges involved, you can kill it, and any ground based target may as well be stationary sitting ducks as far as the ships shooting it are concerned, it's not even target practice...might take advantage of the situation and calibrate the guns while at it though...

edit:
given the technological level that has to be involved, and how the targeting systems on any military space craft would have to be, and given arioch's laser, I'd feel pretty safe standing a few meters from the intended target, assuming a relative low power laser intended for taking out a single human, on kinetic weapons? a few houses away? sure, no problem, the only reason I'd prefer to be a bit farther away is shrapnel from the impact, the weapon WOULD hit the intended building, only thing that could change that would be surface 'defense' fire, and then only to change the trajectory slightly, enough to make it dangerous to be in the area.

i stand by my previous statement given the circumstances if the human commander does not surrender ASAP, he should be shot for treason, at least one of the circumstances must change for this to be realistically viable, take the gunships in orbit(thereby taking away most of the orbital firepower, at least ACCURATE such) out of the equation, or give the humans local support(giving them a chance at hiding), or expecting the fleet back soon....without any of these....even given optimal performance of his troops, there is not a chance in hell the unit would be combat effective after one single month(probably not even a week, or if the hostiles are willing to take serious, not total just serious collateral damage, not even a single day) of engagement.


Fri Mar 25, 2011 1:33 am
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Post Re: Planetary Invasion/Defense
bunnyboy wrote:
You can throw down from orbit whatever you wan't, but on atmospheric entry, friction will throw them slightly of from course, maybe couple to thousands of yards. Any guiding or transmission systems don't work because of heat, until the speed is sloved down. And the time for this is counted in minutes.


Guidance systems in existence now can and do work despite reentry heat.


bunnyboy wrote:
Lasers have problems in atmosphere. Energy around 1 megajoule in cubic centimeter will turn air to plasma, which cause to laser defocus and disperse energy. And any clouds or pollution makes it worse, because they absorb and scatter the light. And when the laser hit the target, evaporated material will cloud and shield the target.


High power laser weapons of the sort described here (a major part of the armament of a fleet of warships) are designed for ranges far greater than those involved in hitting ground targets, moving and accelerating at far higher speeds. They could easily ensure a direct hit on the first shot, and subject a ground target to consistent repeated and sustained fire that no target in space would ever receive. They could reduce power and defocus the beam to prevent ionization, deal with further defocusing due to atmospheric heating and turbulence, and still precisely and reliably kill ground targets.


bunnyboy wrote:
The space fleet can't be stationary, unless having altitude somewhere 36 000 km! That means they aren't constantly present, which gives humans windows to operate.


That only applies if they are in orbit. If their acceleration and delta-v capabilities are at all like those of even the Terrans in Outsider, they can hover above the target at whatever altitude they prefer for the duration of the bombardment.


Fri Mar 25, 2011 8:36 am
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Post Re: Planetary Invasion/Defense
Hello there. I had an idea that might give the humans a chance against orbital warships. If the humans were intending to occupy the planet as a forward base (land grab), they would likely have expected a retaliation by the Logieri.

Now to fortify their hold on the planet, several minelayers might have been included in the human task force and when they had to retreat, the minelayers were instructed to dump all of their mines in orbit. If there is significant orbital debris, the mines might be fairly well hidden and hard to detect and destroy. It could only take several to destroy a large warship.

They could also be under the command of the human forces on the ground and make it very difficult for the Logieri to assume a close enough orbit to give ground support or even land their own troops unless they spend a lot of time clearing everything out of orbit that might be hostile.

If the Logieri need to use planet side facilities to refuel, assuming the humans blew any orbital/moon based facilcities when they invaded and retreated, the Logieri rescue fleet might be limited in manuvering and in how long they can stay before they need their own resupply. Basically, the mines could be used to deny orbital space to the enemy for a time unless he wants to spend a lot of time just shooting space junk.

I reread the OP and saw this;
Quote:
The Logieri counterattacked with a larger fleet than expected and the human fleet chose to retreat and wait for reinforcements before commiting to a decisive engagement.


So the human fleet might still be in the system, hanging around the outer planets. If it is still in-system, that could draw off a significant portion of the Logieri's fleet in an effort to track down and destroy the human fleet or just to keep an eye on them incase the humans try a sneak attack. With a combination of the human fleet hanging around and a substantual mine field laid around the planet, that could seriously hamper any efforts by the Logieri to provide anay orbital suspport for the time being. By themselves, the mines or fleet could be dealt with. Together, they are a fairly hard nut to crack.


Fri Mar 25, 2011 9:42 am
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Post Re: Planetary Invasion/Defense
If a bombarding fleet had to conserve fuel, there's no reason they couldn't spread out along their orbit (or different orbits) to have continuous coverage of a point on a planet without having to climb to synchronous orbit if such exists. That's one benefit having more than one bombard capable ship has. Even if your whole fleet (or single bombard ship) can't keep firing at all times, observation craft should be pretty cheap to have around.

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Fri Mar 25, 2011 12:59 pm
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Post Re: Planetary Invasion/Defense
If the humans have nuclear bomb pumped X-ray lazers, those could be the mines. A lot depends if the Logirei can achieve orbit. If they are intradicted, their options are limited for awhile. If there are no mines, then they will have orbital supremecy and it's a moot point.


Fri Mar 25, 2011 2:34 pm
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Post Re: Planetary Invasion/Defense
Another thing about orbital bombardment...even if it sends the target scurrying for cover, it restricts the targets to staying near cover..."cover" in this case pretty much being something the attackers don't want to destroy. And since the target can't be determined while the projectile's still minutes out, a single projectile can force ground targets over a wide range to abandon what they're doing and try to reach safety, or remain exposed to attack. Preventing your ground forces from being destroyed doesn't do much good if they can't do anything.

It's really hard to come up with a way for large ground forces to even survive when there's a well equipped enemy in orbit. There is at least the fact that weapons for attacking planets would be relatively specialized...red-green lasers or microwave beams with large apertures and short focus and fast pulses to minimize defocusing from atmospheric refraction, and an inventory of kinetic weapons that would be rather useless against other spacecraft. Targeting systems that can see a target against a hot planetary background. Etc...

Why is this large Logieri fleet in the system? Where were they going and what were they equipped to do?


Fri Mar 25, 2011 3:53 pm
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Post Re: Planetary Invasion/Defense
as i said, one of those 'facts' must change...one possibility would be that there was a fight for the orbitals, and both fleets where seriously mauled, so the logieri troop transports are just fine but the entire escort needs a shipyard, badly....and there ain't one available right here... bingo, no orbital bombardment, at least not well aimed and specialized such, could still drop big rock, but not with precision enough to be viable in this situation.


Fri Mar 25, 2011 11:46 pm
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Post Re: Planetary Invasion/Defense
I'm not really sure you'd need very specialized sensors. You'd just need a different optic rather than special sensors. I think all you'd need is a different set of hardware/software pattern matching routines that are used to pick out targets (not convinced you'd need new sensors to deal with the background being much closer to the target in temperature). Compare the special optics to the price of a battleship and the fact that having a targeting computer for orbital bombardment would basically only need to be designed once and would effectively be free to put in your whole fleet and I'd bet they have the capability. As for weapondry, yeah they'll likely have to jury rig something, or just be okay melting a tank and a 20 ft diameter X few feet deep of earth at the same time.

-O


Mon Mar 28, 2011 10:13 am
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Post Re: Planetary Invasion/Defense
osmium: aye, sensors and such, and SEE, no problem, any fleet with a significant ground pounder presence would have surveillance satellites in abundance, the problem would be AIMED weapons, that requires specialized hardware, hitting the right city? probably doable, hitting a tank WITHOUT hitting the rest of the city? without the right gear, not so easy.


Mon Mar 28, 2011 1:35 pm
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Post Re: Planetary Invasion/Defense
osmium wrote:
I'm not really sure you'd need very specialized sensors. You'd just need a different optic rather than special sensors. I think all you'd need is a different set of hardware/software pattern matching routines that are used to pick out targets (not convinced you'd need new sensors to deal with the background being much closer to the target in temperature). Compare the special optics to the price of a battleship and the fact that having a targeting computer for orbital bombardment would basically only need to be designed once and would effectively be free to put in your whole fleet and I'd bet they have the capability. As for weapondry, yeah they'll likely have to jury rig something, or just be okay melting a tank and a 20 ft diameter X few feet deep of earth at the same time.


Detecting/targeting spacecraft and ground targets have very different requirements. A sensor that can pick up a spacecraft's thermal signature might well be entirely blind pointed at a planet...remember the failure of the WIRE telescope that preceded WISE: a lens cap prematurely ejected while it was still pointed at Earth, and it boiled all its cryogen off and spun up to 60 rpm shortly after reaching orbit. In this case, being equipment mounted on a warship, pointing such sensors at a planet will probably just engage protection mechanisms. Optics aren't the issue, dynamic range and ability to handle the high intensity background are.

The sensors would indeed be cheap compared to the cost of the spacecraft, and other sensors would still be of some use, but there's still issues like time for design, system integration, and training personnel for use. It seems plausible that ships not otherwise specialized for operations against planets would have difficulty with the task. For a large fleet to have no ships with such capabilities, though...


Mon Mar 28, 2011 2:53 pm
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Post Re: Planetary Invasion/Defense
Just so you know, your discussion has given me enough ideas for now. And besides, it's gone off-topic as far as I'm concerned. Feel free to continue your discussion, but know that I am no longer looking for an answer to my original problems.


Tue Mar 29, 2011 12:32 am
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Post Re: Planetary Invasion/Defense
Just to note it's common for threads to be derailed into technical hard sci fi sorts of areas.
-O


Wed Mar 30, 2011 10:11 pm
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