Not required, but always nice is some MacGuffinite, that is, an economic or political reason motivating a push for a large number of people living and working in space. Because in the real world there does not seem to be any compelling reason. You can leave out the MacGuffinite but be prepared for a few know-it-alls to pop up and ask awkward questions.
This particular MacGuffinte I am about to offer is rather flimsy and far-fetched, but enough to start you brain-storming a MacGuffinte solution that will fit your needs.
At the start of the RocketCat era of space exploration, happening only mumbly-mumble years in the future, the state of Texas had fallen upon hard times. The prime mover of the Texas economy was the petroleum industry, which was not bringing in as much income now that hydraulic fracturing had become more widespread. Texas needed either a new source of income or a new market for its plentiful supply of electricity. Or both.
Texas noted the steady rise in popularity of the idea of colonizing Mars. In practical terms the concept was utter nonsense. But it was an nifty blue-sky concept to whip up political support among the ill-informed voting public.
And in addition to plentiful supplies of electricity, Texas also had some nice real estate quite close to the Equator. The closer to the Equator, the lower the delta V required to launch into a standard zero-inclination equatorial orbit. True, Texas was not as near to the equator as the ESA's Guiana Space Centre, Puerto Rico, or the Kennedy Space Center. But Texas [a] was part of the USA, not Europe, [b] had a surface area much larger than 9,000 square kilometers and [c] was not rapidly turning into a swamp. Texas also has to the east a long stretch of the Atlantic ocean where spent rocket stages and exploding spacecraft debris can ditch without triggering multiple lawsuits.
Texas' solution is a combination of:
Laser Launching is a relatively inexpensive way to boost lots of payload into LEO. It would open up access to space to everybody from megacorporations down to mom & pop asteroid mining businesses. The launch business would have huge numbers of customers due to the "If you build it, they will come" effect. People would look upon the launch site as a public benefactor.
Is this a new source of income for Texas? Check!
Will all those lasers be a new market for Texas' plentiful supply of electricity? Check!
Building a laser launch facillity when there is no real destination worth launching to is really stupid. The "If you build it, they will come" mentality has its limits. This is where Politics comes in.
Consider the US transcontinental railroad which started construction in the 1860s. 1,500 or more miles between the Missouri River and California with virtually no Anglo-American customers. Just like the laser launcher, it was a road to nowhere.
The transcontinental railroad was built for political reasons, not economic ones. If Texas stirs in some "Colonize Mars!" popularism, they can get the federal government to provide some funding and loans. For a project whose true goal is to jump start the Texan economy, not a benefit for the US as a whole.
Much to Texas' surprise, the laser launcher actually did become a long-term profit center, instead of a short term scam.
It gets started because as it turns out Deimos is a moon of Mars. Texas will be pushing the "Colonize Mars!" initiative, so a Deimos base will provide more excitement to the political effort, and also another nice project to boondoggle and to drum up more business for the Texas Laser Launcher.
The history of Cape Fear starts off very modest. Phase 1 is just a waypoint for a NASA Mars expedition. Phase 2 is commercial, when Texas tries to monetize it.
Then the "Close, But No Cigar" asteroid goes whizzing between Terra and Luna, scaring the poo out of everybody on Terra in general and a few trillionaires in particular.
Cape Dread sells subscriptions to trillionaires offering a luxurious bomb shelter suite on Deimos in case an asteroid actually does target Terra. They will offer a safe place to dine on caviar while having a ring-side seat to watch all the great unwashed masses getting eradicated by the next killer asteroid. And there are other benefits, such as being a tax haven and data haven. The data transmission to and from Terra will have a 15 minute lag time, but nothing is perfect.
During the next few years Cape Dread has an economic boom, building and over-building infrastructure. Eventually the economic bubble pops. But the infrastructure remains. Texas abandons the infrastruture for pennies on the dollar. However the old die-hards of Cape Dread are in for the long haul, they stick around. They become the nucleus of the Cape Dread colony, in the orbital propellant depot business.
And orbital propellant depots are the key to accessing the solar system, since they basically cut the delta-V cost in half.
Meanwhile zillions of small Maw-and-Paw Prairie Schooners start spreading across near space.
And the unit of currency is not the dollar, euro, or bitcoin. It is the MacGuffinite, abbreviated MG. It is vaguely backed by whatever is the major MacGuffinite, but it is not on the "MacGuffinite Standard", like money based on the gold standard. The latter is just begging for a monetary collapse.
TerraGov is the de-facto ruler of Terra, sort of. It is actually a Confederation of the major superpower nations of Terra (science fiction authors reading this get to pick exactly which nations these are).
Having said that, there are plenty of second-string unincorporated nations who are quite angry about this. They are constantly trying to undermine TerraGov, constantly trying to enhance their own power, and constantly helping/hindering other non-incorporated nations according to current expediency. They are a nice rich source of spies, pirates, sabotage, covert support of TerraGov rebels, political intrigue, and other things guaranteed to liven things up. This should start the wheels turning inside the heads of science fiction authors.
Texas Laser Launch Complex
Terra's main surface-to-LEO laser launching site.
Your one-stop shopping for inexpensive prefabricated space habitat kits and furnishings.
They provides tug services for Mom and Pop habitat modules launched from Texas Laser, hauling them to Luna, Mars, and the asteroid belt. The tugs also have emergency services, for a fee of course.
They supplies special ships that fly with Wagon Trains or impromptu convoys taking advantage of Hohmann launch times. The ships contain 7-11 style convenience stores and other services designed to harvest money from travelers.
Assorted short-lived Data and Tax Havens.
An Aldrin Cycler providing Terra-Mars life-support services. You have to supply the delta V for capture and escape.
Largish space station on the main route between Terra and the rest of the solar system (not the only route). Mainly a transport Nexus and a huge orbital propellant depot.
An assortment of space colonies
An assortment of space station with different functions and space colonies. Some are noble, some are shady, some have degenerated into Mos Eisley Space Station, some are falling apart due to the Three-Generation Rule. And most of them grow bamboo. Science fiction writers take note.
Chocolate is a pain to grow on Terra due to picky climate constraints. Chocolate producing regions on Terra are prone to civil wars. Terra cannot produce enough chocolate to meet the global demand. And there are many people who are dangerous to be around when they are undergoing chocolate withdrawal (my wife, for instance).
Hershey is a Gerard O'Neill style L5 space colony optimized as a huge chocolate plantation.
Their orbital factories use precise control gravity, vacuum, radiation, temperature, and energy density to a degree impossible to achieve on Terra. They manufacture exotic substances and nanotechnology.
Sears, Robot & Co.
Sears, Robot & Co. provides the same services that the original Sears did in 1888 for rural dwellers, but to Maw and Paw asteroid habitats. Look through their InterPlaNet catalog website, fill your virtual shopping cart, pay with BitCoins, and Sears will spring into action. The Lunar fulfilment center will package your order in cargo capsules and use their mass driver to lob it at your hab. They even have kit homes, er ah, habitat modules.
And they can even make emergency deliveries of oxygen and other vital supplies. After you have signed away your soul with your signature written in blood.
A strange spacecraft manufacturer that specializes in experimental, customized, and extreme designs. It is run by an eccentric recluse, but the spacecraft are considered top-notch. The location is to take advantage of the rich metal deposits and almost unlimited solar energy available at Mercury.
Oompa Kerbal doom-pa-dee-do
I have a perfect puzzle for you
Oompa Kerbal doom-pa-dee-dee
If you are wise, you'll listen to me
What do you get when you guzzle down d-V?
Burning as much as an SUV eats
You are not getting very high Ace
You're not going in-to Space.
Oompa Kerbal doom-pa-dee-da
If you're not greedy, you will go far
You will live in happiness too
Like the Oompa Kerbal doom-pa-dee-do
Owners of cheap laser thermal rockets need somebody to supply them with laser beams. They can rent laser time from Beams-R-Us. If you have no LT rocket, Beams-R-Us will be more than happy to rent you such a rocket for use with the laser time. But pay your bills or BRU will pull the plug and you'll either find yourself stranded or desperately trying to use the thin gruel of natural sunlight to get somewhere before your oxygen runs out.
Please note that all Beams-R-Us laser arrays contain self-destruct devices controlled by the military Laser Guard. Who also have several laser-hardened warships on patrol ready to blow the snot out of Beams-R-Us' assets if they try to use their lasers to destroy military ships or civilian cities. Oh, did I mention that the self-destruct devices are booby trapped?
The beam arrays are solar powered, taking advantage of a solar flux 6.8 times as strong as that around Terra's orbit.
They have laser arrays like Beams-R-Us, but they use them with company owned cargo spacecraft to make the equivalent of railroads in space. They supply shipping services for people, cargo, and Maw-and-Paw habitat modules.
And like Beams-R-Us, the Laser Guard has them on a very short leash.
The name comes from rail-road trains in the Old American West.
Phobos has no manned presence on it. Because it is in the process of breaking up. Which is bad news for the Mars colonies.
The primary source of liquid hydrogen and liquid oxygen for the inner solar system's orbital propellant depots (OPD). These (along with the Texas laser launcher complex) are key to opening up access to the solar system, since they basically cut the delta-V cost in half.
This also lead to Cape Dread becoming the orbital High Port paired with the Mars low port spaceport on the Martian surface. Which predictably lead Cape Dread to become a Boomtown. Transport Nexus. Giant traffic control complex to keep the ships from colliding. Ship repair docks. Ship construction factories. Warehouses for merchant cargo in transit along with factors for various merchant corporations. Trans-ship point from the Terra-bound clippers to the reusable Mars shuttles. A place for independent asteroid miners to sell their hard found ore. Deimos ice miners, longshoremen, local 235 ice-miner's union.
There might also be wildcat independent Deimosians setting up shop with their own ice processing gear in smaller internal bubble-caves. Old spacecraft too broken down to make the run back to Terra might be retired to serve as surface facilities. Break off the propellant tanks to melt'em down for metal, bury the habitat modules in regolith for protection, take the reactor and use it as a power generator. Use a Mylar bubble mirror with the dilute Martian sunshine to slowly crack water into hydrogen and oxygen, subsist on a diet of algae. Thusly you'd have a habitat shack for an eccentric outer space mountain man. The Old Rocket Bar might actually be an old rocket, selling shots of space booze.
Tourist traps, luxury hotels. Not to mention the pawn shops, clip joints, bars and brothels that spring up around any spaceport or space station, in other words "Startown". Perhaps repo men ready to seize ships where the captain/owner has gotten too far behind on the ship's mortgage payment. The Cape Dread Port Authority would of course need a security squad. And there may be Lurkers.
Think of it like a combination of New York City and Hong Kong. In space. All ruled by mayor Elon Musk the Fourth.
Cape Dread want to stay independent from Mars and Terra since free ports can make more money. The situation is similar to that found in the movie Casablanca. Various national governments (both on and off Terra) want to seize control of the lucrative port. Meanwhile Cape Dread is constantly doing all sorts of shenanigans to maintain independence. Science fiction authors take note.
However, Cape Dread's power is slipping away as the ice mines of Ceres grow and expansion increases into the outer solar system.
But on one point Terra is non-negotiable. While Cape Dread is independent (due to complicated events), the Mars colonies are still controlled by Terra. Mars would like to declare independence but Terra has grabbed them by the short-and-curlies: Mars is utterly dependent upon Terra for its must-have supplies of Phosphorus.
Terra knows that Mars will rise in revolt the instant it obtains and alternate supply of phosphorus so Terra will do almost anything to prevent that. About the only good supply other than Terra is from type C asteroids. So far the Terran Spaceguard has managed to prevent any large-scale shipments of phosphorus from making the trip from the asteroid belt, thus keeping a lid on dreams of a Martian revolutionary war.
Terra's problem is that Deimos is basically a huge type C asteroid.
So Terra has told Cape Dread "Here's the deal: you don't mine any phosphorus and we don't nuke Deimos into blue glowing gravel"
This totally unstable situation will suggest to science fiction authors oh so many juicy and dramatic plot possibilites.
The Martian Colonies
These are still under control of Terra. They would revolt in a heartbeat, were it not for the unfortunatel fact that Terra has a monopoly on supplies of phosphorus. But the instant that monopoly is broken the fireworks will start.
A boom-town similar to Cape Dread. A transport nexus, source of water ice for orbital propellant depots, and other space station services. Plus a small but growing colony. Read Leviathan Wakes by "James S. A. Corey" (first novel in the Expanse series) to get ideas about Ceres colony.
A space station in the same Solar orbit as Ceres, but on the opposite side of Sol. A smaller version of Ceres colony, but without the water ice or the colonists. Contra-Ceres ensures that a belter asteroid miner is never further than about half the Asteroid Belt diameter from a Ceres, instead of sometimes being a full Belt diameter away.
A provider of services to Maw-and-Paw asteroid miners. Services ranging from renting mobile refineries to purchasing ore. Keep in mind that Maw-and-Paw operations are generally limited to mining volatiles, mining metals is for the big corporations.
The largest, roughest, toughest corporation in the asteroid mining business. They do not play hardball, they play granite-ball.
Specializing in orbital propellant depot refills. They maintain a fleet of Robot Asteroid Prospectors (called "water witches") and Kuck Mosquitos. They also market a line of low-powered LH2-LOX thrusters and regenerative fuel cells. Their corporate logo is a "Y" shaped dowsing rod.
Company uses a series of bare-bones installations to breed Helium-3 fusion fuel. They are not self-sufficient at all. On purpose.
A series of asteroid colonies that are sparking a new Renaissance. This could be the start of a new space cultural revolution. Keep in mind that their strength is the fact that each colony is kaleidoscopically different from all the others (as different as Athens was from Sparta). Many have societies that can charitably be described as "disconcerting".
- Aster-Amazons: an all female society reproducing by parthenogenesis. They are of the opinion that the only good male is a gelded male, and they are not talking about anything as minor as a bilateral orchiectomy.
- Singularians: the entire society is geared to do everything in their power to usher in a Vingian technological singularity aka "the Rapture of the Nerds". This is strictly along the lines of developing a computer artificial intelligence, since genetic tinkering with humans is forbidden under the Rigger Ban.
- Hive Society: all members of society are mere cells in the organism which is the Hive. See Hellstrom's Hive and Macro-life.
- Gestalt Intelligence: the society is attempting to forge a Group Mind, where there are many bodies but only one mentality. Current lines of research are trying to develop a brain-computer interface compatible with the local InterPlaNet and with radio-telepathy. We are Nestor.
- Thelema: also known as A∴A∴, Άστρον Αργυρόν (Astron Argon) and Good Ole 451. The society is into psionics and mysticism in a big way. Disturbingly their magick actually seems to work. Their emblem is an odd six-pointed star called a "unicursal hexagram".
- Wierden: also known as the Well of Forever. A society inspired by an old TV show called "Babylon 5" to make themselves into B5 style "Technomages" (using science to give the appearance of wizardry). They have gotten rather good at it. Their skill with flashy special effects and showmanship is only second to their aptitude at computer hacking, electronic surveillance, microelectronics, advanced technology, exotic weapons, covert operations, disguise, and martial arts. Don't mess with them.
- And Many More
Assorted Small Habitat Modules
These will range from the space equivalent of a shack, to a Maw and Paw habitat, to a small mining claim operated by a lone prospector, to a small colony where they have dome raising bees for new arrivals, to small boom-towns.
Callisto is more or less outside of Jupiter's radiation belt, unlike the other three Galliean moons. But it still has a huge supply of valuable water ice. They support the science bases studying the life-forms living in the underground oceans of Europa. They also control the incredibly lucrative power generators and ion-farms of Io
Callisto Matter & Energy Co.
Io is a nasty volanic moon with an annual radiation dosage of around 25,000 sieverts per year.
But between Io and Jupiter's surface is the potential to generate about 2.0 × 1013 watts (i.e., 20 terawatts or a bit more than the total electricity consumption of the entire planet in 2004). CM&E harvests a bit of this bounty by using electrodynamic tethers. On the drawing board is a scheme to use copper rods with microwave power emitters. These would be launched at Jupiter. As the copper cuts the magnetic lines of force it generates electricity. This is converted into microwaves and beamed back to Io. Of course the rods are destroyed when they enter Jupiter's atmosphere, but that's the price of doing business. This is the "Energy" part of "Callisto Matter & Energy Co."
The intense radiation field of Jupiter can be used for the spallation of elements into needed isotopes on an industrial scale. This is the "Matter" part of "Callisto Matter & Energy Co." Of course it is trivial to make huge amounts of weapons-grade plutonium, but other elements are more lucrative.
The isotopes are a valuable export as is. The large amounts of available power can be used to manufacture energy rich substances for export (like antimatter). CM&P is always looking for partners to establish plants on Io for power-hungry industrial processes. You supply the factory, Io supplies the power, both of you split the profits.
CM&P is owned by Callisto Colony, and they maintain a small fleet of armed spacecraft to ensure it stays that way. If you have any bright ideas about attacking that fleet, remember that Callisto can afford to arm it with antimatter weapons.
TerraCo Military Isolation Lab
This is an area where the military develops technologies with hazard ratings approaching Existential Threat level. That is, things that if they escaped control could make the human race extinct. The military's justification for meddling with such insanely dangerous toys is that they don't want to fall behind research done by The Enemy, but the true reason appears to be virtual genital amplification by packing a larger gun.
Broadcasts announce that unauthorized spacecraft breaching the security line will be fired upon with no warning, and they are not kidding.
There are two large task forces in the area. One has all their weapons aimed outward at incoming unauthorized ships, be they spy ships or be they enemy battle fleets trying to grab some goodies.
The other task force has all their weapons aimed inward. In case any of the experiments tries to ... escape.
There are a series of orbital labs. Each is separated from the control complex and all other labs by a healthy distance. There have be a few incidents over the last 75 years or so, but the details are ultra-top-secret.
- Two instances of labs being obliterated by nuclear explosions, apparently from the internal self-destruct system.
- One instance where the lab was nudged into a Sol collision trajectory by a huge remote controlled military fusion tug. During the five year long fall, the lab was escorted by a large task force. Presumably the available fleet firepower was not enough to ensure destruction of whatever-it-was. After the lab fell into Sol and was presumably consumed, the task force invested Sol in a patrol orbit for another three months. Just in case the lab suddenly reappeared and tried to claw its way out of Sol.
- One instance where the lab apparently vanished into an artificial wormhole.
- One instance where the lab started to fractally dissolve and change into a new shape. The popular theory on InterPlaNet is either gray goo nanotechnology or rogue Von Neumann machines. The entire task force frantically bombarded the lab until it exploded, which took a remarkably long time because the blown-up bits stubbornly kept repairing themselves by growing back together.
- One instance where half the guard task force abruptly started attacking the other half. The outer task force destroyed all the guard task force ships and the lab. The outer task force then had all their crews transfer into rescue ships, stark naked through vacuum. The outer task force was then self-destructed. The popular theory on InterPlaNet is that a badly programmed superintelligent AI software tried to escape by taking over guard spacecraft via network firewall penetration and uploading itself into the ship's processing cores like an intelligent computer virus.
- One instance where the guard task force behaved in a strange manner, suggesting that they were under attack by a Langford Visual Hack.
- One instance where a lab exploded with the force of a sub-nuclear explosion. High speed Paparazzi video analysis suggests that a second almost-but-not-quite identical lab materialized overlapping the first lab, causing the explosion due to the fact that two objects cannot occupy the same space at the same time. The popular theory on InterPlaNet is that the lab inadvertently dragged its sister lab sideways in time from an alternative history or parallel time-line.
- One instance where the lab moved at high velocity away from a Paparazzi satellite. Trouble is, there were about a hundred such satellites englobing the Isolation Lab area, and the lab moved away from all of them simultaneously. Which is impossible. The popular theory on InterPlaNet is that the lab fell into the fourth spacial dimension, which is about the only plausible explanation.
Titanic Polymers Inc. (a subsidiary of ReiherCo)
If you are building spacecraft, space stations, or planetary bases; you gotta have some kind of plastic.
If you need something fancier than polyethylene made from agricultural waste, you have two choices. Pay through the nose for fancy plastic imported from Terra with an outrageous shipping charge (ugly 9 km/s delta V) or come to the friendly plastic brokers of Titanic Polymers, on the shores of Titan's seas of petroleum.
They also provide lubricants of all sorts for industrial and domestic use. "If you have two things rubbing together, TitanLube can make it a frictionless action!"
It takes a long time to do Hohmann shipping from Saturn, but since these products have such universal demand there will always be stockpiles available at your local transport nexus.
These are useful locations and institutions for RocketCat's Universe that come from copyrighted works of science fiction. You can use them if you are making a roleplaying game background for personal use only. But you will be breaking the law if you used them in your novel or other commercial project without permission from the original author.
In the year mumbly-mumble some brilliant but misguided scientists were trying to decrease the cost for humans to access space by reducing human's life support costs. Perhaps inspired by Planets in Peril by Edmond Hamilton, they genetically engineer human beings who can live in the vacuum of space with no protection. The new race, called "Riggers", bear a passing resemblance to a skeletal human, abet with some body parts seemingly composed of gristle. In other words, the Dem Bones trope.
You can see where all this is heading.
The misguided scientists are predictably hoisted by their own petard as the Riggers figure there is not enough room in the Solar System for two intelligent races. The Riggers embark on a brutal campaign of human genocide but are defeated since human beings are even nastier.
A hand full of surviving Riggers lurk in obscure areas of the Solar System, occasionally pirating human cargo ships and smelting down the hapless human crews for their component H2O and phosphorus. Or at least the random bits of the crew which remained after the Riggers had feasted on their still-living bodies.
To help track down the remaining Riggers the TerraCo Military Isolation Lab (Saturn-Sol Lagrange Point 4) created the Beast Master program. This was not very successful, since it is very hard for non-sentient animals to operate effectively when wearing tiny four-legged space suits.
The following program hit pay dirt. The Combat-Critter Program genetically uplifted predator animals who had at least a vague friendship with humans. They would hunt down and terminate Riggers.
The most successful is the new species Spatia Catus, and the meanest of them all is RocketCat.
Of course the scientists engineered a kill-switch in all the uplifted animals. Just in case. But when I mention this to RocketCat, he just ... smiles.
RocketCat stands about average human height, has digitgrade legs and a tail (which is kept along the spine inside a space suit and protrudes out a silly hole in civilian pants). The hands have retractable claws which RocketCat occasionally inlays with monoedge blades capable of slicing flesh to the bone and (eventually) cutting through most armor. Since like all felines the claws are shed, RocketCat only inlays for special occasions (wearing fingerless gloves). The hands are modified to be close to human in order to allow operation of standard equipment and controls (not to mention weapons). Fangs and teeth, on the other hand, are pretty much standard cat. Catnip has little or no effect, to deny Riggers an easy weapon (but they can smell it a mile away).
His fur color is jet black, as black as the Boötes void.
Spatia Catus' metabolism has been genetically tweaked so it can produce arginine and taurine, unlike conventional cats. Like ordinary cats Spatia Catus favor a high-protein diet (obligate carnivore), which makes it a challenge to use closed ecological life support systems (they can't live on algae). This makes their feces malodorous, hence the aphorism "mean as cat-poop." I'm sure they get real tired of eating compressed bug bars, and at space stations tend to spend more than they should for restaurant meals of real meat. There is also a remarkable absence of rats around any place a Spatia Catus is bunking. The rats that are too stupid to flee at the merest whiff of cat scent will quickly become a midnight snack.
Spatia Catus is hypersensitive to spoiled and rotted food. They can detect the odor long before it becomes strong enough to be smelled by a human. This gives them a reputation for being finicky eaters.
As with standard cats, they have excellent night vision and can see at only one-sixth the light level required for humans. And poor color vision, they have difficulty distinguishing between red and green. They can hear higher-pitched sounds than either dogs or humans, detecting frequencies from 55 Hz to 79,000 Hz, a range of 10.5 octaves. This includes ultrasound. The hearing is very sensitive being most acute in the range of 500 Hz to 32 kHz. The mobile ears enhance the ability to detect a sound's location. They also have a sense of smell about twice as sensitive as human. Sense of taste is poor, fewer taste buds and they cannot taste sweet things at all.
As with standard cats, they are sensitive to environmental poisons, because their livers are less effective at some forms of detoxification than are humans. This also includes many medications. Some standard human drugs are quite poisonous to Spatia Catus. As is chocolate, poor kitty.
Standard cats raised as pets live in a kind of extended kittenhood (neoteny). They see their owners as a cat mother surrogate. Not Spatia Catus, they are strictly feral, and are not domesticated. At all.
Spatia Catus are not sexually compatible with human beings, for reasons you will discover if you research feline male genitalia. You will then understand why female cats have to be so deep in estrus that they are cross-eyed before they will let a male cat anywhere near them.
RocketCat has been highly trained to detect, track, hunt down, and sanction with extreme prejudice Riggers. He has carefully honed detective skills, is a dead shot with most firearms, and is a master of a peculiar martial art called "Cat-Fu". As most cats RocketCat has inate skills with acrobatics and parkour. He has also been trained in microgravity hand-to-hand combat.
He travels in a small torchship with a freaking nuclear salt water engine that don't need no steenking Hohman orbits. It also don't need no steenking stealth, you can track a continuously detonating atomic drive from as far away as Proxima Centauri. The spacecraft was constructed at Winchell-Chung Astronautical Industries, of course. He humorously named his ship the Polaris. It has a delta-V of 200 km/s, carries a crew of five RatBots and is armed with a Casaba Howitzer containing six nuclear rounds. The ship's armor has a foil-thin core that RocketCat is evasive about, but I suspect it is steel made with muon-iron (roughly 207 times as strong as conventional steel).
The Polaris is run by a sardonic artificially intelligent computer named GAZAK, if HAL is one letter ahead of IBM, then GZK is one ahead of HAL. GAZAK and the RatBots are quite capable of taking care of themselves. The gutters around the starport occasionally contain the mortal remains of idiot punks who thought RocketCat's empty spacescraft would be an easy burglary job. GAZAK also has a hobby of infiltrating the local node of InterPlaNet and hacking into every government, police, megacorporation, and other computer it can access.
And a word to the wise: when RocketCat is in town, do not torture or kill any domestic cats. RocketCat will find out and he takes such things very personally. The police will find your mutilated corpse with every wound and injury inflicted on the kittycat painstakingly recreated on what is left of your body. A fact the police can readily ascertain due to the convenient presence of a reference hologram of the poor kittycat victim. Convenient because it is nailed to your skull. Underneath the hologram, your final agonized facial expression has been know to give police and forensic experts nightmares.
Yes, there have been assassination attempts on RocketCat using a cat-kill as bait. Every time the end result is an unharmed RocketCat and all members of the assassin kill-team being found dead and identically mutilated as per above. As well as whoever hired the assassins in the first place.