How would you invade a planet?

[jeff_wilson]

Originally Posted by trans

Are you in a hurry? If not particularly, really really try to get better intel and use diplomacy to divide and conquer. It worked for the conquistadors, together with unplanned bio-warfare.

This. Or even use the incredible trade advantage you have to buy concessions from the natives, as described in some of the flashbacks in A DEEPNESS IN THE SKY.

[Varyon]

Originally Posted by reverse_atomic_roger

Keep your space ships hidden. Drop a single inanimate tungsten rod on an American military base. Either they assume it was the Chinese and retaliate, or they do nothing. If they retaliate you wait for the worlds superpowers to wear each other down, then move in with your fully rested, well equipped troops. If they don't retaliate you launch another single tungsten rod. Repeat until there is retaliation or you run out of targets.

You'll most certainly want to do some solid intel first - not only to determine who the world powers are, but to determine how far they'd be willing to go in a retaliation. Something like this might work today, but back during the Cold War it could have resulted in a nuclear holocaust - great if you want to wipe out the inhabitants, not so good if you want to colonize any time soon.

There's also the issue of hiding - space is a big place, and without superscience cloaking devices your invasion fleet is likely to be seen from quite a ways off.

[Figleaf23]

Originally Posted by Dangerious P. Cats

Assuming you have a late TL8/early TL9 military and some super science space travel for a military modelled as much on modern earth militarise as possible given that they are from space (I don't know much about abut modern military structures so I'll leave it to the experts) how would you go about invading a planet that is essentially earth (except that there are enough cosmetic differences that the planet's inhabitants constitute aliens, but TL8ish with equivalent social structures). The reason for the invasion is that the planet has breathable atmosphere and compatible Eco-systems that your superiors want mostly in tact. Gear wise you have space carrier ships the equivalent of aircraft carriers and space battleships the rough equivalent of battleships. The only weapons of mass destruction you have are tungsten projectiles that can hit with the force of a nuclear bomb and biological weapons are not terrible workable. Otherwise you have gear equivalent to that of the modern military, maybe slightly more TL9, though all flying vehicles are assumed to be able to fly in both space and atmosphere and you don't have a terrestrial navy of any kind (really just a space army and space Air Force). The planet you're invading is much like earth, mostly tech level 8, different nations of varying size that squabble a bit, international bodies that try their darnedest to stop the squabbling, different languages and cultures about the place. While rudimentary translation of the major languages is possible you also have little intel to go off. They will probably unite in defence though.

So, what are your invasion plans?

Maybe make a covert landing in one of the more powerful states, induce them into a deal with the devil, and slowly replace their leadership with shape-shifting lizards?

[Agemegos]

Originally Posted by Dangerious P. Cats

So, what are your invasion plans?

I have essentially no tech edge, and the locals can nuke any beachhead I establish? The locals have about 20 million troops and for a successful assault I need five to one odds, and never mind the occupation afterwards?

Umm. The guys upthread are right: this is going to require an indirect approach, and adopting a local proxy is the tried-and-true.

Just for a bit of variety I'll point out that the bosses want the biosphere and breathable atmosphere intact and didn't say anything about the population and the installed industrial based. Biological warfare is ruled out by the OP, but we have OKK weapons ("tungsten rods"). A systematic attack on energy and transport infrastructure (including large-scale irrigation) could wipe out eighty percent of the net food supply; in a few years you'd have cut the population by eighty percent and in twenty years knocked at least one TL off the tech you'd be facing. And it's very cheap. The problem is that it's going to make what's left of the place very hard to govern.

Can we start sneaky? I liked the idea of faking a nuclear strike on a nuclear power. With a bit of finesse you can start the impression that this is a local squabble, and then knock out communications before it gets straightened out. That ought to set up a morass of confusion and rumour rather than uniting everyone against you.

So how about this: hammer some early-warning radars, then some missile fields and government centres. Give it a couple of hours, then take out the communications satellites, space program control centres, radio telescopes, and astronomical observatories. Then hammer broadcast comms. You will probably get some of the locals "retaliating" against others, and in any case no-one is ever going to convince everyone of what really happened. Then hammer major ports (including gas, oil, and coal terminals) and strategic canals, land transport nexuses, reservoirs, hydroelectric, oil, gas, and coal power stations. Do not attack military sites and weapons per se, but don't give them a pass if they have other value. Don't bother setting fire to the cities. You probably want to avoid setting fire to forests.

[Agemegos]

Originally Posted by Varyon

There's also the issue of hiding - space is a big place, and without superscience cloaking devices your invasion fleet is likely to be seen from quite a ways off.

Stealth in space is fundamentally very difficult when you are facing sensors that are also in space and that are designed to detect spaceships. When you are hiding from ground observation that has to look up through ninety miles of warm air, and when no-one has built a spaceship-detecting network it is a fair bit easier. Hit the astronomical observatories (including orbital ones) and the space control centres (to be on the safe side); no-one else much is in a position to detect small sky objects using IR.

[jeff_wilson]

Originally Posted by Agemegos

Can we start sneaky? I liked the idea of faking a nuclear strike on a nuclear power. With a bit of finesse you can start the impression that this is a local squabble, and then knock our communications before it gets straightened out. That ought to set up a morass of confusion and rumour rather than uniting everyone against you.

Maybe start sneaky and finish duplicitously: Intervene in the conflicts you instigated, and pull a low-budget THE DAY THE EARTH STOOD STILL by adding FX to your ortillery and spectacularly destroying their further capacity to make war in the name of interplanetary peace. Then you can govern as a benevolent occupier with the old national loyalties taking the blame and being further dissolved each generation.

[malloyd]

Originally Posted by Agemegos

I have essentially no tech edge, and the locals can nuke any beachhead I establish? The locals have about 20 million troops and for a successful assault I need five to one odds, and never mind the occupation afterwards?

Yeah, this looks to me a lot like stay home and use the world conquest capable army they are giving me to stage a coup to replace our terminally idiotic leadership has better odds.

I can *probably* sit in orbit and kill anything a TL8 civilization can launch at my ships, though losing a few wouldn't be impossible. There's no way I'm winning a conventional war against the whole planet unless my invasion "fleet" is a world ship with a billion people on it. I'd need at least roughly as many troops as their entire combined forces and the industrial production capabilities of a continent to have a chance without more of a tech edge than that.

[Gedrin]

"Greetings people of Not-Us. We have a cell phone with twice the pixels of your most advanced model that gets way more internet speed. It's for sale! We've also invented YouTube...that's free." Then you just buy a bunch of land and move in. In a few years they'll be up to speed, increasing your culture's overall idea diversity. This has the advantage of automatically filtering for dynamic native societies willing to live in a multi-sentient environment, as incompatible native societies will severely restrict your commercial access.

For a more bellicose solution...

Scout the world while the fleet is far out. Launch a massive number of small (sub kton) kinetic strikes. Grab space rocks if you need. Time the strikes to arrive within the shortest possible window. The strikes target all aircraft/large missile maintenance and staging facilities. First message to the world,"You are denied flight. We will be taking possession of Australia."

You need either cooperation or sufficient fear to prevent them from attacking. The risk/reward balance needs to work for the natives, otherwise... Well...imagine the ingenuity and destructive power of 8 billion human beings who all agree that someone needs to die.

[malloyd]

Originally Posted by Rocket Man

Of course, the stereotypical Earth invader might not understand human psychology well enough to use "divide and conquer" very effectively.

This is the most likely way to set up a disaster like this really. Many species here on Earth respond to attackers that can demonstrate they obviously can severely injure or kill them by submitting. If the aliens arrive expecting humans to give up without a fight, or at worst after a short demonstration that shows resistance will hurt a lot, they could get into serious trouble. If they aren't willing to let it turn around and become slaves of the humans themselves....

[Agemegos]

Originally Posted by Gedrin

"You are denied flight. We will be taking possession of Australia."

Hah! Right into our trap!

This is a place where the brown snakes eat the black snakes.