Today, I have decided to engage my infinite improbability drive and write about something near and dear to my heart. Science fiction is full of cool gadgets, gizmos, and tropes. This is about something that encomapsses all three - WORLD KILLING! This post if for all you sci-fi buffs playing Traveller, D20 future, or what-have-you.
So, as a galactic overlord of a conquering armada, you are crushing the upstart hoo-mans fleets as fast as they come. Unfortunately, these rabbit breeding apes have colonies ALL OVER THE @##$$%$ PLACE! In fact, one of your logistical weak points have been underscored by this turn of events - that it is incredibly impractical to have enough disposeable troops in a fleet to pacify more than a single planet with any reasonable expectation of success.
It's simple. People (or their equivalent) take up space. So does their gear. Their weapons, their food, their water. Their siege engines, their ammunition, etc, etc, etc. To "properly" pacify a single planet would likely require at the minumum hundreds of thousands of troops with all of their kit. If the environment is hostile to the invading species, even more gear is required. This makes planetary invasions incredibly cumbersome. As a result, space warfare will likely be comprised of efficient and impersonal methods.
Greetings sir, I am first technical officer M'lorik of the artificer caste. It is my honor to present our findings on the most efficient means of eradicating the Hoo-man menace. As you know sir, the Hoo-man beasts reproduce prodigiously, and have spread to no less than 100 worlds in a roughly 200 light year globe centered on their homeworld.
After several disastrous attempts, we have determined that this species make terrible slaves, and as such, only a small number will be preserved for zoological purposes.
#1 - Cobalt bombs - AKA the Neutron Bomb
Sir. for your pleasure we offer this option as the most optimal to destroy the ape menace. As you can see, they are incredibly easy to make and 100% lethal to any mammalian creature not adequately shielded from the immese amount of ionizing radiation.
As you can see from this chart, the ape's fragile bodies can withstand only small amounts of hard x-ray and gamma radiation. Within 24 of their hours we could saturate the entire planet with enough ionizing radiation to kill every creature not buried beneath or behind several tones of ultradense material. This option is optimal because it leaves their infrastructure intact, and requires no interaction with their filthy species.
#2 - Biological warfare
As the demands for the uncommon element cobalt may tax our reserves unnecessarily, another option on the same scal would be a bacteriophage. Unlike our self sanitizing carapace, the apes' bodies are cesspits of disease and filth.
Our options in this regard are limitless, their frail bodies are susceptible to so many microorganisms, a list would take days to completely read. Suffice it to say, our current plan involves using some of the captive research specimens to distill a phage that would do the trick nicely.
With a little bit of work, we can even make it persistent, so that they may never come back to this world again! Luckily, we (being Boron based) will be completely immune to this plague. This option also allows for the infrastructure to remain largely intact, and requires no actual contact with the filthy creatures - save the researchers, who will be immediately put to death to prevent the spread of the ape's effluvium.
#3 - Nanotechnology
The ape's primitive technologies cannot protect them from our superior nanotech. Using bulk matter converters, we can unleash a gray goo plague. With a few nanosmiths left behind to manage "things" it it entirely reasonable to expect that we would return in 2-3 cycles to mountains of processed materials awaiting pick-up.
The drawback here, sir, is the extreme cost of assembling and maintaining a nanocolony on a planetary scale. While theoretically possible, you of course know that once a nanocolony reaches a critical mass, it tends to experience fits of pre-sentience, and can be difficult to control.
#4 - Orbital nuclear bombardment -
With the low resource expenditure required to assemble and field a large quantity of nuclear fusion weapons, this option seems to be one of the two most optimal fits. The strategy is laughable simple, we simply assume geostationary orbit and saturation bomb a planet wide swath for a full day cycle.
While the local infrastructure will be mostly obliterated, the destruction and widespread radiation will work to passively eradicate any and all survivors. This option will be unavailable on any world identified as creche worlds or breadbaskets for obvious reasons.
#5 - KISS (Kinetic Interdiction Strike System) or (Relativistic Kill Vehicle)
Sir, lastly we have your personal favorite - The K.I.S.S. of death. By firing solid slugs massing several tones each, we can effect the equivalent of the strategic yield nuclear bombardment previously mwentioned - without the harmful radiation as a side-effect.
Much like the the battle of Proxima Centauri, where you so wisely hurled our own damaged and wrecked hulks at their orbital forts! While ultradense materials work best, we could conceivably use asteroids from the system belts as ammunition.
Yes, sir. I have it on authority from our weapon keepers that the larger vehicles will actually convert several feet of ground cover into component atoms for hundreds of miles around each impact site. Yes sir, we have perfected the device you requested, and as such will discuss it now.
#6 - The Planet Buster
As you specified, we have manufactured a conical shaped projectile using uranium as the base material, and neutronium as the outer ablative layer. IT measures 300 feet in length, and is 90 feet wide at the base.
At the core of this device is a small magnetic containment field with a reservoir that may store up to 4 pounds of antimatter. The expected yield would be in the order of 4-6 gigatons. At relativistic speeds, the spike will penetrate deeply into the inner mantle of the planet before detonating with enough force to tear the planet apart in mere minutes.
Yes, sir. Destruction is total. We currently have only one prototype, but with the final push into the Sol system coming up, we have taken the liberty of prepping it for deployment. These beast should have accepted servitude to the Donny empire when they had the chance. It will be our pleasure to teach them the error of their ways. ALL HAIL EMPEROR DONNY!