Video Game / Kerbal Space Program

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Kerbal Space Program is a game about a green humanoid species known as the Kerbals, as they start a space program. Superficially similar to Orbiter, the difference between the two has been likened to the difference between making to-scale miniatures for architectural design and playing with LEGO bricks with rocket fuel in them, which you then hurl with glee at your sister.

The game offers three game modes to suit your style of play. The first is little more than a sandbox. You're set loose upon a space center complete with a vehicle assembly building and a launch pad, a bin full of rocket parts, ground personnel composed entirely of yes-men who build and wheel onto the launch pad anything you design no matter how crazy it is, and some astronauts to crew your creations. The second version is Science, in which you have to conduct experiments in order to unlock various piece parts, as you start off with just the very basics. The third mode is full blown Career mode, and you have to juggle a budget, job offers, your Kerbalnauts and conduct Science similar to the Science mode (which used to be the old Career mode, prior to 0.24). Essentially, you have to manage the entire Space Program. The number of parts has risen dramatically in recent releases, and the community is already cranking out fanmade addons at an impressive pace on top of that.

After four and a half years of development, version 1.0 was released on April 27th, 2015. This version, on top of taking the game out of Early Access, added the last gameplay mechanics that were left to implement: Aerodynamics, heating, fairings, resource mining and, last but not least, female kerbonauts. The game is still being developed, though, and is currently in version 1.0.5, with 1.1 promising a new Game Engine version.

Its official website and download location is here, and a trailer for the game can be found here. Starting with 0.19, it's also available on Steam. A Wii U version has been announced.


This game contains examples of the following:

  • Aborted Arc: At one point, there was a plan for a loose narrative connecting the Easter eggs. Then, Nova Silisko (the person who conceived it) left the team, and this story is most likely abandoned.
  • Ace Pilot: Pilot Kerbals can enhance the control of vessels, allowing them to point to particular vectors and enhancing their existing stability systems, getting that much more mobility out of craft. The more experienced they are, the better they get. Although, once you unlock the probe cores that can do everything a veteran pilot can, they become somewhat obsolete.
  • Aerith and Bob: Somewhat odd example - all the Kerbonauts have names that sound fairly Middle American, but anyone who is not an orange suit has a name randomly generated from a list of prefixes and suffixes. So alongside Jeb, Bill, and Bob may sit Melzer, Bardrin, or Billy-Bobfred.
    • Although there are some characters who are named after historic space personages ("Buzz", for instance) or famous Kerbal Space Program Let's Players.
  • After Action Report: Many players like to share accounts of their most recent or most memorable accomplishments. The Mission Reports section of the official forums is set up explicitly for this. People also like to assemble collections of screenshots into captioned Imgur albums and share them as brief Machinomics.
  • Alien Sea: Eve, whose oceans are purple and (according to the devs) literally Made of Explodium.
    • The Outer Planets mod has Tekto, the Titan analogue. The oceans are green, and presumably made of hydrocarbons
    • Laythe’s oceans seem pretty normal – until you realize they are liquid at a subzero temperature.
  • Alien Sky: Eve again, with a thick, heavy purple sky. Laythe also counts; from some angles it looks a lot like you could be on Kerbin until you turn around and see a massive gas giant hanging in the sky.
  • Alleged Car: Rovers are a bit... unstable at the moment, sometimes shaking themselves apart or exploding with little reason. The devs are working to correct this for version 1.1.
  • And I Must Scream: Kerbals don't need food or water, meaning if a vehicle is stuck on the moon, orbiting somewhere or flying out into space, those Kerbals won't die and suffer a Fate Worse Than Death. They don't seem to mind, though.
    • Various life support mods are used by players who do want them to die.
  • Arbitrary Headcount Limit: Until the VAB and SPH are upgraded, you are limited to a size restriction (to fit within the hangar) and a total parts number restriction. There's no weight to a parts value, meaning you may have to choose between a Mainsail rocket booster or a handheld thermometer, because putting both on would put you 1 part above the limit.
  • Artificial Atmospheric Actions: In the VAB and SPH, mostly consisting of various personnel trying to look busy and important.
  • Artistic License – Physics: The game is generally pretty good about using real physics, but that makes the few places where it goes off of it stick out more. For example, a satellite is only calculated to be in one celestial body's sphere of influence at a time, making all exo-atmospheric orbits stable without Lagrange points. Mainly, this is due to engine limitations,note  some of which the developers hope to improve in future updates.
    • Though Squad has actually written on their FAQ page to stop asking for Langrangian points to be implemented, much to the chagrin of several astronomy nerds (the L4 and L5 points are ideal places to put a long-term space-station).
  • Art-Style Dissonance: Don't let the cartoonish proportions of the kerbonauts or their rockets fool you; the game is deceptively difficult if you don't already know a little bit about how actual rocketry works.
  • Ascended Glitch: The Space Kraken. A dead one can be found on Bop, one of Jool's moons.
  • Ascended Meme: The loading screen roll references a few that are popular on the forums, such as "Adding K to Every Word", and contract descriptions occasionally use the phrase "Kraken help you if..."
  • Asteroid Thicket: Averted. While there are asteroids added in the aptly-titled Asteroid Redirect Mission update, they are few and far between, and players have to go out of their way to detect them in the first place, let alone rendezvous with one, conduct experiments, and even change its course.
  • Awesome, but Impractical: There's nothing preventing you from making a rocket far larger than one you really need to complete the mission.
    • The ion engine. The most fuel efficient engine in the game by far, but it's expensive, uses a lot of electricity, and has a very low thrust output (despite still being several times more powerful than real-life ion engines, especially due to a recent update that upped the thrust level appreciably). As a result, the burn time needed to get anywhere interesting can take hours, and you can only accelerate time up to 4x when engines are on.
    • The nuclear rocket isn’t much better, being huge in length, rather low on thrust, and merely twice as efficient as regular ones. However, 1.0 has really given it a hard hit by making it not using oxidizer, which leaves you carting around half-empty fuel tanks in any nuclear rocket configuration.
  • Badass: Jebediah and Valentina Kerman, along with many other randomly generated Kerbals if they have a hidden "BadS" trait set to true. They always smile no matter what's happening and even if something explodes, they get worried for a few seconds before resuming their smiling. If either of them looks freaked out, you have done something horribly wrong.
    • A possible coincidence: If you take the hex code #BADA55 and turn it into a color, that color is close to the shade of Kerbal skin. (The actual color is #CBDB81.)
  • Base on Wheels: At its most basic level, you could just slap some large rover wheels onto a Hitchhiker Storage Container and call that a base. Anything more elaborate depends on your imagination and engineering and piloting skills – and mods.
    • Man contracts require the bases to be mobile, because they’re easier to assemble into larger structures that way.
  • Beautiful Void: Only one planet in the whole system has (debatably) intelligent life although there is evidence for it on others, and even that planet is mostly empty aside from your Space Center and a few other locations of note (as of 1.02). Some particularly enterprising modders are working to make the place feel more lived-in, literally.
  • Beyond the Impossible: It's supposedly impossible to land on the gas giant, Jool, because it's a planet that's made of gas. Yet the player can do so anyways. The sensors recommend that you don't think too hard about it.
  • The Big Board: Both the Tracking Station and the in-flight map view allow you to see statistics on the various bodies in the Kerbol system and monitor the progress of your active flights.
  • Bilingual Bonus: The Kerbal language is Spanish, played backwards and sped up.
  • Billions of Buttons: Inverted for comedic effect. Kerbals have a joystick and a Big Red Button for commanding the modules, and... that's about it.
    • Obviously, the modders were right on it, with cockpits based around RasterPropMonitor are sufficiently instrumented for all-IVA flights.
  • Body Horror: Kerbals on EVA can suffer from somewhat disturbing physical glitches when subject to extreme g-forces.
  • Boring Return Journey: Averted. Returning to Kerbin from another planet is usually just as challenging as getting to your original destination was, and often more so if you're low on fuel and have to get creative...
    • Almost any return to Kerbin involves airbreaking, which is not Frictionless Reentry and is quite dramatic.
  • Brick Joke: Just about all the science parts warn you in their descriptions that the "warranty will be voided if X happens" (X usually being a mundane or obvious use for the part). If you somehow manage to land on Jool and run a seismic scan, you get the following message:
    The sensor has informed you that the warranty has just been voided. No refunds.
  • Camera Perspective Switch: If your rocket has a manned cockpit, you can switch to an Intra Vehicular Activity camera and experience the ride from the inside.
  • Captain Crash: Building your own vehicles is one thing, landing them is another. Mun Landings, for instance, often end in the vehicle tipping over and falling to pieces, leaving the Kerbonauts stranded until help arrives (or backup help when the help befalls the same fate).
  • Centrifugal Farce: Featured in the 0.21 release trailer.
  • Chest of Medals: A series of service ribbons with a host of devices are available for use in signature lines on the KSP forums, indicating what planets you've been to and what you've done there. There is even a mod that tracks the careers of your Kerbals in-game, updating their ribbon and medal counts using the same criteria.
  • Cloud Cuckoo Lander: Jebediah Kerman, who always smiles all the time, no matter what is happening. Unless something goes wrong.
  • Colony Drop: The introduction of the Asteroid Redirect Mission allows the player to attach ships to asteroids and redirect them to impact other celestial bodies. There is no particular reason to smash an asteroid at high velocity into a planet though, except as a Self-Imposed Challenge. However, managing to safely land an asteroid on another celestial surface can give another opportunity for additional scientific data.
  • Construction Is Awesome: The game's primary appeal is that it lets you design, build, and fly your own spacecraft, space stations, and surface bases, including the possibility of assembling them part by part in orbit or on another planet's surface. See also Design It Yourself Equipment.
  • Context-Sensitive Button : Docking Mode allows you to use the normal rotation keys for RCS translation maneuvers, although it isn't strictly necessary as you can also translate from the main keyboard configuration using different keys. You can also define custom action groups when designing a vehicle, so that you can, for instance, press one key to extend all of your solar panels at once instead of having to do it one-by-one.
  • Convection Schmonvection: Depends a bit on the circumstance. Engines dump heat into nearby parts, which can cause overheating if multiple engines or boosters are attached to the same part, but Kerbals standing directly in rocket exhaust don't seem to overheat. However, it is played straight when it comes to shedding heat: parts with lots of built-up head lose that heat my quickly in thicker atmosphere, while parts in space take quite a while to cool down due to having no contacting fluid to pass heat into. A vessel close to something like the sun that has insufficient radiating surface area can actually find itself overheating from the small but continuous sunlight because there is literally nothing for it to have convection with.
  • Conveniently Close Planet: Averted, even taking into account the Space Compression. Even getting to the Mun is a challenge for the newest of new players, and traveling to other planets requires quite a bit of planning and forethought — even more so if you plan on going home.
  • Cool Car: Rovers are essentially meant to be Cool Cars In Space. Now, whether this succeeded or not is up to some interpretation...
  • Critical Existence Failure:
    • Your Flight Log may tell you that parts take damage from engine exhaust, but this damage seems to have no effect on their performance at all until they're destroyed outright.
    • Overheating does not affect the performance of parts at all, until the overheating bar is full and the part vaporizes into a puff of smoke.
  • Death Is a Slap on the Wrist: Selectively averted with the 0.21 update, which allows you to enable permanent deaths for your pilots. You have to hire all of your astronauts, and when they're dead, they're gone for good. Previous versions of the game did play the trope straight, however, and you still can if you leave the option disabled (which is the default).
  • Design It Yourself Equipment: The full game comes with a small selection of prebuilt designs, but if you want to do anything really impressive, you'll have to design and build your own rockets, probes, satellites, etc.
  • The Dev Team Thinks of Everything: It's supposedly impossible to land on the gas giant, Jool, but they do have responses to performing science experiments on the "surface" such as the EVA report.
  • Diegetic Interface: The vanilla game has virtual cockpits on the majority of crew pods, with an artificial horizon sphere, surface/orbit speed, vertical speed, and indicators for subsystems such as SAS. The RasterPropMonitor Game Mod adds multifunction displays to the cockpits, allowing you to play almost the entire game from first person - you can even get out of the MK1 cockpit by pulling the canopy lever.
  • Difficult but Awesome:
    • The LV-N Atomic Rocket Engine is the largest and heaviest engine in its size category, has trouble with decouplers, and has one of the poorest thrust-to-weight ratios in the game. Its thrust is so poor that it is almost useless on any ascent stage, limiting it to final stages only, which because of the aforementioned weight and decoupling issues, takes a lot more effort to get into orbit than lighter engines - and good luck landing back on solid ground when the engines are twice as tall as any landing gear. However, if you can get them up there, they are the single most fuel-efficient liquid-fuel consuming engines in the game. They are one of the most popular options for interplanetary vessels for this reason.
    • The First Contract (0.24) update makes this apply to reusable spaceplane designs. Designing and piloting them are both difficult to master, but the relative cheapness of fuel compared to parts and the fact that they can be piloted back to and recovered at the Space Center for a complete refund on their parts value makes them highly cost-effective for transporting crew, experiments, and small probes into orbit.
    • Certain advanced maneuvers such as gravity assists or aerobraking can save a lot of fuel when done properly.
    • Asparagus staging is a very efficient method of storing fuel because you can drop the added weight of empty fuel tanks easily and frequently. It also takes a lot of careful placement and tweaking to get it to perform correctly, or the rocket could easily become unbalanced or wind up ejecting full tanks. The multiple external fuel tanks can make for some unwieldy rocket designs too.
    • With version 1.0 comes ore refinement equipment, giving the player the ability to mine ore then turn it into rocket fuel and monopropellant. Now you can keep rockets gassed up without having to expend any parts or performing additional launches. Except that both the critical components to this are very heavy and one of them is radially mounted which of course can lead to headaches trying to get the thing stable. The process will also usually require several specialized space ships to transfer fuel from the base then get it into orbit again. To cap this all off, in career mode (where rockets actually cost money and refuelling them is helpful) many contracts require using spaceships built after the contract was accepted, so you'll still have to launch new spaceships anyway.
  • Diminishing Returns for Balance: The amount of scientific benefit you get from performing the same experiment multiple times in the same environment slowly decreases until you end up getting nothing out of it at all. This is supposed to encourage players to send craft to many different environments, both around Kerbin and elsewhere in the system. Recent updates have made this effect even more pronounced.
    • Happens in ship construction too, though this is more of a realistic effect than anything hard coded into the engine. Basically the larger a rocket is and the more boosters added (after a point), the less efficient the rocket becomes. This is mostly because the more fuel is added to a rocket in later stages the more fuel is consumed in earlier stages getting that fuel to where it needs to be. Using additional engines makes things less fuel efficient and adds weight that must be moved around.
  • Disaster Dominoes: Any accident that doesn't involve your rocket crashing into the ground wholesale usually involves these, and even that is often only the last domino in a chain of design and piloting mistakes.
  • Disposable Vehicle Section: Any multi-stage craft will be built this way, and completely justified. After all, getting to orbit requires a lot of propulsion and fuel, and once up there the empty fuel containers and excessively large engines just become dead weight. Any craft that averts this is called a single-stage-to-orbit vehicle, and depending on engineering and mission goal can range from Awesome, but Impractical to Difficult but Awesome.
  • Dissimile: Eve's in-game description:
    [Eve] is considered by some to be an almost sister planet to Kerbin. Well, despite the purple, and the toxic atmosphere, and the extreme pressures and temperatures... Actually, it’s not very similar at all is it? Who are these people?
  • Dramatic Space Drifting: Can happen if a Kerbonaut on EVA runs out of fuel before he makes it back to the capsule.
  • Drives Like Crazy: Several of the multi-ton cargo and utility vehicles in the Spaceplane Hangar are apparently driven by speed-obsessed maniacs, including at least one who loves to drift in circles around much larger vehicles and another who nearly causes a three-car pileup by trying to thread between two moving vehicles.
  • Drop Pod: The addition of airbrakes in 1.0 allows players to slap them on Lander Cans to turn them into one-man drop pods. The airbrakes are powerful enough that only 4 are required to slow down a Mk1 Lander Can from orbital velocity to a safe landing speed.
  • Drop Ship: Possible to build - though ususally of the civilian variety, unless you take "conquering space" literally - and in many cases far more practical. Landers that detach from transition modules to go to a planet's surface and back are a common and practical example. Space Planes that deliver small probes are another kind of example. Sometimes it is even possible to build an entirely VTOL design. Cupcake makes many good examples.
  • Earn Your Fun: Figuring out how to build a rocket that will actually achieve orbit, let alone go places, can be a challenge for new players. But this is a game that rewards persistence and a willingness to endure failure, and gives experienced players a universe of possibilities.
  • Easily Detachable Robot Parts: With clever use of docking ports and probe cores, you can create completely autonomous spacecraft from modular components that can operate independently of the main craft as well.
  • Easy Logistics: Individual craft have limited fuel and electricity, but (discounting monetary costs) that fuel is effectively in infinite supply for your space program as a whole.
    • Also you never have to worry about food, water, or oxygen supply. This actually makes manned missions in some ways easier than unmanned ones (as unmanned command modules require electricity to run).
  • Easter Egg: "Anomalies" scattered across the surface of Kerbin, Mun, and other bodies.
  • Edutainment Game: While the original game is not primarily designed as one, its creators support its use in the classroom as a teaching tool and have been working on a special edition called KerbalEdu specifically meant for classroom use. At least one teacher has incorporated it into his classes.
  • Ejection Seat: It's possible to create a (very clumsy) ejection seat for rovers with the use of miniature SRBs and a decoupler. With the NASA update, a real-life equivalent from the Apollo program is available for regular cockpits - the Escape Tower, a vectored SRB mounted on the top of the cockpit, which can be activated (in unison with a decoupler) in an emergency to lift the entire cockpit to safety.
  • Emergent Gameplay: Quite a few people find ways to have fun with the game without launching rockets into space at all, or by finding unusual uses for game parts. Geofley's Cove, a fully aquatic base on Laythe, is one of the less outlandish examples.
    • Another excellent example is The Wrong Brothers, in which a player goes through career mode using only the spaceplane hangar and runway, and never launches a single conventional rocket.
    • Update 1.05 overhauled how buoyancy is treated in the game making it possible for some parts and even entire craft to sink. It is possible to build submarines and underwater bases, there are even contracts a records for them.
  • The Engineer: Engineer Kerbals, obviously. They can repack parachutes, fix broken rover wheels, and enhance the function of surface ore drilling equipment.
  • Enormous Engine: The obvious result of sticking 2-meter diameter engines on 1-meter diameter fuselages or fuel tanks. More particularly, this is true of any launch vehicle, which is simply an enormous engine to get your (relatively) tiny spacecraft or probe up into orbit. Said launch vehicle tends to discard pieces after they are spent on the way up, gradually shrinking the size of the "engine" until only smaller ones remain.
  • An Entrepreneur Is You: The 0.24 update introduces an economy system to Career Mode to provide funding and contracts for your space program.
  • Epic Fail: Half the fun of the game is watching your carefully crafted creations explode, go way off-course, or slam into Kerbin at hundreds of miles per hour.
    • A classic and popular one is releasing launching clamps before activating engines. This can easily happen due to a buggy staging sequence. As the result, your majestic rocket will slowly fall to the ground, exploding stage-by-stage on contact, until all that remains is the crew capsule sitting in the middle of the launchpad empty save for the ring of the aforementioned launching clamps.
  • Escape Pod: doable to various degrees, but can easily result in dead weight. Implemented as a mod by Umbra Space Industries: the Deployable Emergency Reentry Pod is an inflatable one-man shelter atop a miniature propulsion block. It's still less insane than the real-life General Electrics Manned Orbital Operations Safety Equipment.
  • Everything Breaks: Since the 0.25 update, the buildings of Kerbal Space Center are destructible if hit with enough force. While potentially fun, this is generally considered a bad thing as destroyed buildings cannot be used until the player coughs up the money to rebuild them (in career mode at least.)
  • Explosive Overclocking: Cramming too many engines too close to one another and firing them all at full throttle is guaranteed to make them overheat rapidly. Let them get too hot, and all those engines will explode spectacularly.
  • Explosion Propulsion: While this is arguably true of any liquid or solid fuel rocket (no Orion Drives in the unmodded game, yet) some players find creative uses for rocket exhaust:
    • One common design Fan Nicknamed the "Mass Relay" has two powerful rockets facing opposite each other, designed to go to full throttle immediately and simultaneously. Each rocket cancels the thrust of the other, but any object placed in front of one of the nozzles will be launched away at high speed. This is often used as a feature of space stations to move small masses without needing to have their own propulsion.
    • And then you have the massive abuse of decouplers known as "Plaid", named for how fast it goes (nearly 1 million meters per second - fast enough to reach the Mun in 13 seconds, or the Sun in 4 and a half minutes).
  • Expospeak Gag: A few of these have crawled into the fan vocabulary from real-world rocketry, notably "rapid unplanned disassembly"Translation  and "lithobraking."Translation  The latter is a legitimate landing technique that can be used in-game successfully, but most of the time the term's used in the ironic sense.
  • Face Palm: Gene Kerman (the guy at Mission Control) does this if you cancel a contract.
  • Fearless Fool: A common fan interpretation of Jebediah Kerman's personality. The description of him on his Steam trading card supports this.
    "Fearless? Brainless? Who can tell?"
  • Fictional Counterpart: Weird names and minor tweaks aside, KSP's set of planets is essentially the same as ours. After a small, rocky planet and one with a very thick atmosphere, Kerbin is the third planet from its star, followed by a small red planet, then a small rocky object (the counterpart to Ceres), then a huge gas planet with lots of moons, and so on. Saturn, Uranus, and Neptune equivalents are missing from the stock game, but do exist as a mod.
  • Flanderization: According to the development staff, the attitude implied by, among other things, the use of the word "kerbal" as a synonym for "ridiculous and impractical" is a result of the fandom taking one aspect of the Kerbals' approach to rocket science and blowing it totally out of proportion. To quote this development blog post:
    Bac9: Overall, I'm convinced the obsession with disasters and perception of Kerbals as worthless engineers only caring about explosions is destructive for the game. KSP deserves much more than being a glorified disaster simulator where rockets falling apart and crews being killed is the prime entertainment and the only expected result.
  • Flying Car: Rover wheels + rocket parts = Hilarity Ensues. Skilled builders may elect to place wings, control surfaces and tailplanes on the car, in an attempt to make it more or less a proper flying car.
  • For Science!: Literally in career mode, where doing experiments, sending reports, and collecting samples in various environments both terrestrial and extra-terrestrial accumulate science points used to unlock the Tech Tree. Generally, the further out from Kerbin you go and/or more inaccessible the location (Eve, for instance), the higher the multiplier for doing science becomes, thus "For Science!" is a wholly rational justification for conducting missions.
  • Frictionless Reentry: Played straight during development. Fully Averted in version 1.0, which added the heat effects from re-entry that had been absent in the alpha and beta releases (unless you used the Deadly Reentry mod).
  • Fun Size: Kerbal proportions are quite odd compared to those of humans. For one, their heads are ludicrously oversized.
  • Funny Background Event:
    • One of the engineers in the rocket assembly area randomly hits the floor with his hammer.
    • Some of the engineers are carrying tire irons around.
    • The large group of Kerbals in reflective vests and carrying lighted batons, doing... Well, it's not really clear. Semaphore lessons? Yoga?
    • On the Munar loading screen, an empty helmet will sometimes roll across the Mun's surface in the distance.
    • A sandcastle on the Mun can sometimes be seen in the background.
    • The service trucks added in 0.21 to the VAB and SPH drive around, but you will occasionally see the trucks drifting.
  • Future Copter: Any air-breathing stock VTOL will necessarily be this. As the stock parts have no rotatory wings, the only way to have any upward thrust is via downward-vectored engines, typically jets.
  • Game-Breaking Bug:
    • If you attach your engines directly to the large orange fuel tank, it has a nasty habit of causing said engines to overheat much faster than normal. Fortunately this can be fixed by adding a smaller fuel tank to the bottom and taping it up with struts, or by using two normal fuel tanks that are half the size together.
    • Landing physics, especially when high impact speeds are involved, can be dicey. For example: trying to land on Jool causes the entire solar system to disappear, crashing a pole of incredibly tough struts destroys the planet you crashed into (unless it's Jool) and even trying to create an artificial ring around the planet would cause the ground to disappear.
      • Trying to make a new jetpack design with the external seats? Bye-bye, Kerbin!
    • When RCS thrusters were first added, they were programmed to have more thrust when they were closer to the ship's center of mass. Since there wasn't any cap on this, having an RCS thruster dead on the center of mass would give it infinite thrust, crashing the game.
    • The game has picked up a reputation for devouring memory, especially if mods are added, as the game must load every single asset into memory upon starting. Viewing the Space Center causes memory usage to increase, and it will increase with every successive view. Nasty memory leaks crop every once in a while, such as the part overheat gauge in version 1.0.0 causing the game to crash within minutes once a part starts to overheat.
  • Game Engine: Built with Unity3D.
  • Game Mod: The game is extremely mod-friendly, and several mods have been directly incorporated and their makers hired on as developers. One of the fanbase catchphrases is "There's a mod for that", since there are so many, from autopilots to atmosphere, from vital features the devs haven't got around to yet to fun and wacky parts like soccer balls.
  • Gameplay Automation: The "MechJeb" user-made addon adds an autopilot feature to the game. Since each autopilot program is a separate "module" (with one for docking, one for ascent, one for rendezvous, etc), it's the player's decision how much they want to automate their flight.
  • Guide Dang It: One of the game's few flaws is that (as of yet) there is little in-game documentation of how most things work. You'll have to learn either by a lot of trial and error, by reading up on and applying actual rocket science, or by watching tutorial videos on YouTube.
  • The Hard Hat: Kerbonaut helmets are apparently hard enough to survive impacts that would otherwise kill the wearer.
  • Hilarity Ensues: Common in the official promotional shorts, most of which involve some poor kerbal suffering Amusing Injuries by ignoring some basic rule of spaceflight safety.
  • Hitbox Dissonance: In older versions of the game, a few of the buildings at the Kerbal Space Center had some wonky collision meshes, such as the SPH being about 10 meters taller than it actually appeared to be.
  • House Rules: Prior to implementation of a proper campaign mode, some users had created and shared their own systems for handling funds and tracking pilot stats as a Self-Imposed Challenge.
  • Humble Beginnings: The original "Kerbal Space Program" was the background for a series of model rocket launches by the developers when they were teenagers. More than a decade later, they decided to use the idea as the basis for a video game.
  • Human Resources: The "Kethane" Game Mod comes with the KE-WAITNONOSTOP-01 Kerbal Unreconstitutionator, which can recycle Kerbal astroanuts into kethane (to refine into fuel)
  • Hurl It into the Sun: Perfectly possible, but by no means easy. Doing so from Kerbin orbit requires at least four kilometers-per-second of delta-v, and that is including a Spaceship Sling Shot Stunt, or twice the amount of delta-v without one. Just getting there is a major Self-Imposed Challenge for some players, though getting a close flyby (by astronomical standards) can be a big boon to science in career mode.
  • Improbable Piloting Skills: Often times directly proportional to the improbability of the craft.
  • Infinite Supplies: Kerbals do not require oxygen, food, or any other supplies and can run literally forever. Averted for the various rocket fuels, which will run out and forms the basis for the game's difficultly.
  • Interplanetary Voyage: No science-fiction technology for you — if you want to explore the local solar system, you have to do it the old-fashioned way, with rockets and orbital mechanics.
  • In Space Everyone Can See Your Face: Kerbonaut helmets don't have mirrored reflective visors. This is presumably so that the player can get a kick out of watching their expressions change when something goes horribly wrong.
  • In-Universe Game Clock: "Internal Game Clock" variety. Time normally passes in real time and is recorded in Earth minutes, hours, days, and years (with, since 0.23.5, an option to switch to Kerbin days and years, where each day is 6 hours and each year is 426 days). Thankfully, as some missions could take a very, very long time in real-time, there are options for time acceleration. Each planet and moon has its own day-night cycle determined by its motion within the solar system, which is important when planning landings or using solar-powered probes.
    • Hit So Hard the Calendar Felt It: Whatever the reason, the game always starts on Year 1, Day 1, 0:00:00. Which just so happens to be the middle of day in the Kerbal Space Center.
  • I Don't Know Mortal Kombat: Aside from the abovementioned Lu fiasco, there is noticeably little use in remodelling the real-life Lunar Orbital Rendezvous system in the game’s miniaturized environment. The mass of the additional engine, the Mk 2 Lander Can, the supporting electrics, the manoeuvring engines and fuel for them, and the docking port – all in all, another, albeit lighter, spaceship – does not justify the delta-V savings from not having to take the return fuel up and down the gravity well.
  • Iron Buttmonkey: As long as the Kerbals are not killed outright, they can come out of some spectacular disasters none the worse for wear, allowing for some serious Video Game Cruelty Potential (see below).
  • Jet Pack: Every Kerbonaut has an EVA pack to prevent him from floating away from his vessel. It only works as a traditional jet pack on low gravity bodies, though on the smallest objects, it is possible to achieve orbit. It has 20x the fuel of a real life jetpack.
  • Lens Flare: You can see the effect whenever your camera is pointed towards the sun.
  • Little Green Men: The Kerbals are green, and approximately 0.75 m tall.
  • Loads and Loads of Loading: This will definitely happen if you have a low end computer, or if you have a 3,000-part ship being put on the pad.
  • Made of Explodium: Rockets have a habit of blowing up on occasion, usually during stack separation or when insecurely radial-mounted pieces "wobble". Justified by most of a rocket's volume being fuel containers which in turn hold most of the rocket's mass... mass that is itself a two-part combustive compound designed to explode preferably slowly and in a controlled manner. Pretty much Every Rocket Is A Pinto.
    • Every single part, regardless of function, will explode when it hits the ground with enough force.
    • Starting with 0.25, all of the buildings at KSC explode and get destroyed in a fireball if hit with enough force. The water towers appear to be filled with Kerosene.
  • Made of Iron: In contrast to the Made of Explodium rocket parts, Kerbonauts are incredibly durable. Besides never running out or air or needing food or water on multi-year space journeys, they can somehow survive crashing into the ground at up to 45 m/s (about 100 MPH) completely unharmed. Your ship's landing gear will snap off and/or explode at one-third that speed.
    • It's been speculated that it's in fact their helmets that are Made of Iron. Landing a Kerbal on their legs will generally kill them instantly, but if you flip them over and land them on their helmets, it's possible to survive.
  • The Many Deaths of You: Blowing up in liftoff, drifting into the void of space to starve or freeze to death, spinning madly on the launch pad, hurling yourself into the sun - there's no end to the creative ways these guys can perish.
  • Meaningful Name: As mentioned under Aerith and Bob, some of the randomly generated names are Shout Outs to real-life people (like Buzz Aldrin or notable KSP lets-players). Furthermore, Valentina Kerman is named in honor of Soviet cosmonaut Valentina Tereshkova, first woman and first civilian in space.
  • Mechanical Horse: Yes, you really can build one. It's entirely made from stock parts, too.
  • Mohs Scale of Science Fiction Hardness: 5.5. While the game uses realistic Earth technology and Newtonian physics, it is also meant to be accessible to the average Joe and used as a teaching tool, which softens it up a bit. Think of it as being able to fly really cool model rockets that can land on other planets.
  • Money for Nothing: Zig-zagged. In the early game, it's difficult to make money. However, once you reach orbit, many contracts with easily fulfilled objectives (rescue missions, science data from space, etc) open up allowing for Money Grinding. Unless you build seriously over-engineered rockets, you will always turn a healthy profit on contract missions, turning out huge sums of moola to spend on silly and/or expensive endeavors.
  • Mother Ship: This is probably one of the most popular and efficient methods of inter planetary travel. Even if the mother ship in question isn't reusable, its still a lot more efficient to bring a big ship that can deploy a lot of probes than to just repeatedly send probes to almost the exact same place, or to cart interplanetary vessels to and from the planet.
  • Mundane Dogmatic: No aliens (bar the kerbals themselves), and all technology present is equivalent to modern-day or near-future / in-development rocket tech.
  • Nerves of Steel: Jebediah Kerman almost never loses his cool. If you can get him to crack, the odds are good that your spacecraft is already doomed.
  • Nintendo Hard: The game is pretty harsh and unforgiving if you don't know what you're doing; most new players take a while to achieve their first orbit, partly because of common misconceptions about how real rockets reach orbit (you don't need to go up very far, but you need a tremendous amount of horizontal velocity). Even if you've mastered the game, a single mishap can ruin that epic Jool mission you poured hours into.
    • While building finely balanced, efficient rockets and sending them to other worlds may not be particularly easy, this pales in comparison to trying to build a Single Stage to Orbit (SSTO) space plane and docking with your orbiting space station. Seriously, try it!
  • No Antagonist: The only obstacles to your progress are your own design or piloting mistakes. That and the harshness of space.
  • No One Gets Left Behind: A popular form of Self-Imposed Challenge is to always, always make a rescue attempt for any Kerbonauts stranded far away from home unless they're plainly lost to the clutches of space. See Video-Game Caring Potential below.
  • No OSHA Compliance: Parachutes, landing gear, or anything to insure the survival of your Kerbals are entirely optional. It is even possible to make rockets that face down.
  • No Plot? No Problem!: There's no real story or backstory to the game aside from player fanon. There's just you, your space program, a ton of rocket parts, a solar system filled with planets and moons, and an endless supply of eager would-be rocket jockeys.
  • No Pronunciation Guide: The pronunciationof the Mun
  • Not the Intended Use: See Emergent Gameplay above. For example, since fuel tanks are buoyant, you can build rocket-powered speedboats with the right parts.
  • Oh Crap!:
    • Bill & Bob Kerman always look worried whenever the spacecraft is doing anything other than holding still. All characters do this if something explodes. If Jebediah ever stops grinning... see above.
    • With the addition of other Kerbonauts, it has been revealed that each one has a personality based on certain modifiers, which in turn determines how brave or cowardly each one is. One of these modifiers is if the Kerbal is trained as a pilot or not (either yes or no). If he is a pilot, he will be mostly happy. If not, he will scream his pants off.
    • Bob will always look terrified. He'll only calm down if the craft is confirmably drifting back to the surface slowly via parachute or has come to a complete, safe stop.
  • Omnidisciplinary Scientist: Science Kerbals have no specialization, they are all experts in generic Science! They can clean out and refurbish otherwise expendable experiment modules, enhance the degree of science gained from experiments, and staff laboratory modules to conduct longer-term research. There is, at least, a distinction between scientists and engineers.
    • The basic science devices are also like this. One is the "Science Jr.," a big cylinder full of nondescript "samples" that react to their environment, and the other is a tank of "mystery goo." You can research more specific tools, like thermometers and barometers.
  • One-Gender Race: All Kerbals appeared to be the same gender while the game was in beta. Averted starting with 1.0.
  • Orion Drive: Via a Game Mod made by the webmaster of the hard science website Atomic Rockets. In true Kerbal fashion, the first test fire of the drive caused the command module to go flying off the top of the ship like a cork on a wine bottle.
  • Outside Ride: Kerbonauts can ride on the outside of rockets by holding onto ladders, but they don't have especially strong grip (so be careful if you try it yourself and never try it when the craft is accelerating). Version .20 added seats; see Rocket Ride.
  • Perpetual-Motion Monster: If one were to dump Valentina on the Mun with nothing more than her spacesuit, she could sit there until the heat death of the universe. They also have infinite stamina, and they can shrug off any amount of G-forces. Various mods force you to feed, water, and/or oxygenate your Kerbals, but in the stock game they can only die from high-speed impacts or incineration, much like inanimate objects.
    • Before the introduction of re-entry heat, if one had the EVA Parachutes mod, it was completely possible to perform interplanetary EVAs.
  • Quicksand Box: The game can be unforgiving sometimes, but fortunately there are a wealth of videos and forum threads out there to help, and there's plenty of fun in trying to figure out what gets out of atmo without ripping itself apart.
  • Reality Ensues: You may spend hours recreating a ship from your favorite sci-fi story only to find that it flies like a brick in the air or spins uselessly in zero-g... or tears itself apart as soon as you put the throttle up.
    • Also, sure you can build a nice Global Airship to visit all the cool easter egg landmarks around Kerbin. You also have to take the time to sit around and fly it yourself, plus land it without crashing.
    • There is a steep valley on the Mun that was added in one of the patches. Naturally when this was discovered, the first thing the fanbase did was fly there to recreate the Death Star run. This turned out to be much less exciting with real world physics (and without enemy gunfire, as well). All you need to do is create a low enough orbit to pass through the canyon, cut engines, and gently thrust away from the walls.
    • Wait, there's asteroids now? Awesome, let's go make like Han Solo - Oh, wait, they're millions of miles apart.
  • Reentry Scare: With heating introduced, this is a justified state in some cases, especially if you’re dealing with a spaceplane, which doesn’t just have an ablative heat shield.
  • Refining Resources: Version 1.0 added ore that can be mined across various planets, and scanners to detect concentrations of it. This can allow refueling as ore can be converted to fuel, however, this can be hard to do at times as both the drill and the converter are rather large.
  • Resources Management Gameplay: While the Career mode has to deal with reputation, science, and funds on the strategic level, every gameplay mode has to deal with resources on a mission level. These include number of crew, electric charge, reaction control propellant, and especially fuel (crew support like oxygen and food are thankfully infinite.) Since sending more of these things into orbit requires expending them in ever greater quantities, there are seriously diminishing returns for trying to take more with you, so efficient use of them is necessary.
  • Retro Rocket: It's not impossible to build and operate a reusable SSTO "tailsitter" rocket like the trope depicts, merely very, very difficult. Having a fueling station at the destination or in-built ISRU capabilities are highly recommended if you want to make it somewhat practical for more than just quick orbital or suborbital hops. On the other hand, many rockets will look retro on takeoff, but will most definitely shed parts on the way up.
  • Rocket Ride: 0.20 introduced official support for seats, mainly intended for rovers. Of course, sticking one to the side of a large rocket and launching it into the stratosphere was one of the first things a lot of users did.
  • Rule of Fun: Squad's response when anyone asks them if they will do anything to make the game more realistic is "Would that make the game more fun?" If they think it will, then they will try to incorporate it, and if not then they will let it slide. Some things are intentionally unrealistic for the sake of fun; the entire universe has Space Compression applied because using real-life scales would make climbing to orbit and reentry/landing rather tedious.
  • Sci-Fi Writers Have No Sense of Scale: The developers avert this but the use of this trope in media has caused some confusion among players less familiar with actual astronomical scales. Even among those familiar with space flight don't always remember exactly how big space really is. For instance, some have suggested ignoring time acceleration (i.e. being able to increase the speed of the game) and instead allow the program to run essentially in the background to allow for realistic flight during extended missions. Even acknowledging that a single mission would very well be months long, they don't seem to realize that most of that time would be spent doing... nothing.
    • The distances are less than they would actually be, but that's due to the Space Compression. The scales for Kerbin/Mun/sun are roughly the same as for Earth/Moon/Sun accounting for it.
  • Self-Imposed Challenge: Making ridiculous rockets, making manned ballistic missiles, making space shuttle equivalents, spacecraft that look like specific patterns, achieving orbit, reaching relativistic speeds, getting a huge and completely pointless concrete cube into orbit, landing on the moons of Kerbin, landing on other planets, landing on the sun, flying to the North Pole, flying to the other Space Center, etc.
  • Series Mascot: Due to his Memetic Badass status, Jebediah is the most recognizable of the Kerbonauts.
  • Shout-Out- Often found in the equipment part descriptions
  • Simple Yet Awesome: Encouraged by the Career mode introduced in the 0.24 "First Contract" update. Each rocket part now costs funds, of which the space program only has so much at any one time, making simple rockets with inexpensive and easily recovered and refurbished parts necessary for accomplishing elaborate objectives, where an unrestricted mode might favor flashier and less humble designs.
  • Simulation Game: It's not on the same realism level as Orbiter, but it's realistic enough to be a great way to learn basic orbital mechanics.
  • Single-Biome Planet: Zig-zagged during development. Kerbin up to version 0.17 was mostly grassland, with the exception of the poles, which were icy. 0.18 and above added rivers and deserts. Version 0.22 and 0.23 added a variety of "biomes" to Kerbin, the Mun, and Minmus, which will give different research data when experiments are performed within them. Finally averted in 0.90, which added biomes to every celestial body in the solar system (except the sun and Jool).
  • Slapstick Knows No Gender: Valentina Kerman and the other female Kerbanauts are no more explosion-proof than their male counterparts.
  • Snowy Screen of Death: The individual video feeds for each Kerbal will cut to static if they are killed.
    • Removed as of 0.16, but hopefully we'll see a return.
  • Soft Water: Averted. A hard splashdown can outright destroy a spacecraft and its unlucky passengers.
    • In fact, splashdowns are often actually more dangerous than landings on solid ground, since when a spacecraft hits the water, it doesn't slow down very quickly. Consequently, all or most parts on it must pass a check to see whether or not their actual splashdown velocity exceeds their rated maximum impact velocity. If it does, they're destroyed. Often, this leads to oceans swallowing up entire spaceships, leaving only a few high-impact-tolerance girders or decouplers bobbing in the water. By contrast, when a spaceship impacts land, the first parts that hit the ground absorb some of the impact velocity and it decelerates much more quickly, giving parts (and crew) far away from the point of impact a chance of survival.
    • The 1.05 update made water, while not soft, at least softer, by giving the simulation a new buoyancy model. Craft that are properly shaped and hit the water at the right angle can certainly survive at velocities that might shatter less aquadynamic designs. Even seaplanes are viable if built right!
  • Something Nauts: Kerbal space explorers are called kerbonauts.
  • Space Compression: To cut down orbit times and prevent the game from becoming astronomically boring, Kerbin is a mere 1200km in diameter. Jool, the gas giant, is roughly the size of Earth. The orbits of planets and moons are similarly scaled down. All in all, the Kerbol system is roughly 1/11th scale... except for mass. Kerbin weighs about the same as Earth, meaning it's equally difficult to get to orbit on either planet, roughly.
  • Space Does Not Work That Way: Averted en masse. Hooray science!
    • Not counting certain glitches or the Space Kraken, of course...
  • Space Friction: Averted; spacecraft obey Newtonian physics and will slow down only under power or when passing through an atmosphere. Objects that achieve escape velocity from the star will fly away into the infinite void.
  • Space Is Noisy: Even in the depths of space, you can still hear rockets and explosions.
    • Partially justified in that most of those explosions happen either in-atmosphere or when you're still attached to the thing blowing up/making noise, giving the sound a medium on which to propagate to your ears.
    • Averted when using certain mods.
  • Space Plane: Possible to build, though not easy in the slightest.
  • Space Station: A basic space station isn't too difficult to put into orbit. Making anything elaborate is dependent on your docking skills, and the ability of your PC to load large numbers of parts.
  • Space Whale: A very minor example, but one selection of music for when a ship leaves the atmosphere and enters space is unmistakably whale song. What this means is anybody's guess.
  • Spaceship Slingshot Stunt: The game lets you pull off realistic gravity assists, both to gain a lot of speed or to shed it, depending on which side of the gravity well you try to sling around.
  • Speaking Simlish: Kerbals speak Spanish that is sped up and played backwards, making it almost unrecognizable. Contract messages are in English but may as well be in Simlish because it's all incomprehensible word salad gibberish.
  • Spiritual Successor: KSP can be thought of as a very distant descendant of Lunar Lander, one of the earliest video games.
  • Stuff Blowing Up: If any part of a spacecraft hits the ground (or another part) too fast, it makes a nice explosion. The interesting thing is that parachutes and scientific equipment make the same explosion as, say, fuel tanks full of rocket fuel. These explosions seem not to harm other parts though.
  • Struts For Everything: For the moment, the best solution to any problem involving the rocket coming apart is simply "Add more struts." This may change when the atmospheric drag model is overhauled in future versions.
    • Can be significantly reduced by using a mod.
  • Subsystem Damage: Each individual rocket part has its own parameters, including heat and impact tolerances. With a little luck, you can even save your crews from crashes that will destroy the rest of the vehicle.
  • Succession Game: The International Youtube Space Station, assembled by various players who contribute one module each.
  • Suspend Save: While your game autosaves periodically to prevent blatant Save Scumming (not that it really needs to at this stage), there's also a single-use quicksave feature that allows you to save at various points during a mission so that you don't have to launch an entirely new rocket if your current one suddenly becomes a million-dollar lawn dart.
  • Suspiciously Specific Denial: Found in the descriptions of various rocket parts:
    • The X200-8 fuel tank is totally not a stolen swimming pool frame
    • The Atomic Rocket Motor is harmless. Mostly.
    • The scientific thermometer is totally not a store-bought model, and admitting that it is voids its warranty.
    • Taken to extremes with the Not-Rockomax Mini Node, which is so obviously not a miniaturized version of an already-existing part that the (in-universe) manufacturers helpfully point out the complete lack of a resemblance in the name.
  • Tech Tree: A feature of the game added in the .22 update. Kerbonauts and probes can now gather science in flight in Career mode, which you can use to research technology to unlock more parts.
  • Tertiary Sexual Characteristics: Female Kerbals have noticable eyelashes, longer hair, and a smaller more oval head compared to the males. But apart from that, they still have the same exaggerated body proportions.
  • Those Magnificent Flying Machines: The fanbase has made some strange contraptions that, against all odds, still fly. See Good Bad Bugs.
    • More particularly, any aircraft on Eve actually flies more easily than it does on Kerbin thanks to Eve's atmosphere being five times thicker, which makes even improbable designs workable. Especially since any such craft cannot functionally use jet engines due to the atmosphere lacking oxygen with which to power their internal combustion, and it must use other methods of thrust.
  • Tidally Locked Planet: Mun is tide-locked to Kerbin, Duna and Ike are locked to each other, and all five of Jool's moons (Laythe, Vall, Tylo, Bop, and Pol) are locked to their primary.
  • Tim Taylor Technology: Fan lore is that almost any problem you have with a rocket can be solved with "MOAR BOOSTERS!!"
  • Too Dumb to Live: The numerous shorts Squad has made to advertise the game are filled with this behavior. The worst offender? One kerbonaut finds that a wrench he needs has somehow gotten into his helmet. So, he decides to take his helmet off to get it. While standing on the Mun. Which has no air. And another kerbal reacts to seeing the ownerless helmet rolling around by grabbing at his own helmet as if it might spontaneously come off.
  • Too Fast to Stop: Docking accidents, flipped rovers with blown-out tires, "unplanned lithobraking"... There are many ways you can run into this trope in the game.
  • Transforming Mecha: Difficult in the base game, but the Infernal Robotics Game Mod adds many servos and pistons to make transforming vehicles. More modest designs include spaceplanes with retractable powered wheels to function as a (clumsy) rover or alter their lift surfaces mid-flight for optimizing their behavior. More fantastic designs include a replica of Starscream from Transformers
  • Truth in Television: Sure NASA and the other space programs have brilliant engineers and scientists to build their spacecrafts, but sometimes things go a little Kerbal anyway. The tragedies are, of course, tragic, but those aside, here are a few more lighthearted examples:
    • This note painted on the Shuttle Carrier Aircraft.
    • The Soviet N-1 Moon rocket with 30 engines on the first stage is quite Kerbal. It is a result of a familiar issue of not having large-diameter parts, and spamming the smaller engines.
      • N-1’s competitor UR-700, never going off the drawing board, has a nearly unbeatable kerbalness quotient. All of thousands of tons of its propellants were the toxic, carcinogenic hypergolic fuels; it used the Direct Ascent principle popular among KSP players; it had not one but nine vertical stacks, because the designers wanted all the parts to be rail-transportable (which is much like a Kerbal player dealing with lack of sufficiently large parts); it had fuel crossfeed from the first stage into the second stage, also fired at launch; and its orbital stage had its own strap-on boosters.
    • When training for the Moon landing, Neil Armstrong bailed out of the "Flying Bedstead" aircraft after losing control of it. His fellow astronauts were amazed at how unfazed he was by the incident.
    • Those who find rendezvous and docking to be difficult and counterintuitive may take comfort in the fact that early astronauts in the real world got off to a rocky start with it themselves. Gemini 4 was America's first attempt at having two different craft rendezvous in space. Unfortunately, neither the astronauts nor the ground crew fully understood the orbital mechanics involved, and so as they tried to thrust towards the target from a higher orbit, they ended up actually speeding away from it, which is completely backwards from how things are on the Earth's surface but makes perfect sense once you realize that they were thrusting into a lower orbit by firing against their own orbital velocity, which would make them orbit faster in the long run.
    • The game's fandom (at least on the official forums) rejoiced on at least two occasions due to mentions from people who work in space science. The first was when Neil deGrasse Tyson tweeted that he thought the game looked fun and would probably spend "far too much time" playing it if there was a Mac version. (This resulted in the until-then low-priority OSX port becoming the absolute #1 priority for the devteam!)
    • The second was, if anything, an even bigger reaction when, in response to a question on their blog, NASA's Curiosity Mars rover team stated that there were a number of people on the team who liked to play KSP during their free time. The unpaid endorsement by a group of REAL rocket scientists (or close enough to it for all practical purposes) set off tears of joy from the user base.
    • Former Astronaut Ed Lu played the game with Scott Manley, Ed's first flight crashed in less than 30 seconds, the second got into space, but not into orbit. Despite not making it to orbit in-game, he still described it as "fun to play", which is pretty fair praise, too.
  • Unexpectedly Realistic Gameplay: See also the entry for Art Style Dissonance. While it's fairly easy to build and launch a simple rocket, actually getting that rocket into orbit or to places other than Kerbin is fairly difficult if you're more used to less realistic space simulators.
  • Unfinished, Untested, Used Anyway: There's nothing that says you can't try to go straight for the Mun (or anywhere else) with a full crew in a rocket that you just built and aren't sure how it will perform. There are a few perfunctory checks to make sure that you haven't forgotten anything important (like parachutes for a safe return), but you're not even obligated to adhere to those. Fan lore is that the kerbal species as a whole is like this — they're so excited about exploring space that they'll gladly strap themselves into the rockets they've built without bothering to test the design for flaws first.
  • Videogame Caring Potential: Some players equip their crew capsules with not only parachutes but various other elaborate safety and/or abort systems, rescue all stranded Kerbals, and try to land returning ships as close to the Kerbal Space Center as possible...
  • Videogame Cruelty Potential: ...while others take gleeful pleasure in sending the hapless trio to die in the cold blackness of outer space. Or just blowing them up.
  • Video Game Cruelty Punishment: ... and then in career mode starting with 0.24, losing Kerbals will reduce your reputation, lowering the quality of the contracts that are offered to you because losing crew makes you look incompetent to investors.
  • Violation of Common Sense: The best way to land a falling Kerbal? On their head. Their helmets can survive practically anything!
    • With this in mind, you can usually save a Kerbonaut from a doomed aircraft by simply having him step out the hatch while low enough to the ground.
    • You'd think the more advanced antennas would be better in some way, but they're actually worse. In the stock game, the high-tech ones transmit faster than the basic Communotron 16; but a few extra seconds hardly matters when most space missions have days or even weeks of downtime, and the better antennas weigh more, cost more, and use more electricity. The devs do plan to fix this at some point, probably by limiting the range of the cheaper antennas.
  • Weaponized Exhaust: An (often) unintentional example of using this on yourself if you are not careful with spaceship construction. All engines have heat tolerances which, when exceeded, will damage the engine. Too many engines too close together can overheat each other at full thrust, and other parts of the spacecraft too near the exhaust might be damaged as well.
    • Also, if anything comes loose near a working engine, even a Kerbal, it will be launched off into the horizon at unsurvivable speeds, so standing near engines in general is not a good idea.
  • Weird Moon:
    • Apparently Minmus doesn't make a lot of scientific sense. The wiki has since been updated with a detailed and quite well-researched Hand Wave for most of its abnormalities.
    • Laythe also has liquid water and surface temperatures that would let humans -and presumably kerbals- walk around near the equator with nothing but a warm coat and a rebreathing mask, despite being much too far from the sun for this to be possible without some other mechanism. However, the developers have cunningly placed it in a Laplace orbital resonance with 2 other Joolian moons. The heating is supposed to come from the tidal interaction between these objects, in the same way that Io is kept hot enough to have volcanoes in our own solar system
  • Wide Open Sandbox: In Sandbox mode, money has no importance and there are no goals. 0.22 has added a rudimentary campaign with a limited selection of starting parts and the option to unlock more by researching your way up a Tech Tree, while 0.24 has continued to flesh out the campaign with funding and reputation systems to place additional limits on your space program. Even then there's no storyline as such, and you're free to do whatever you want within the limits of your available parts.
  • The World Is Just Awesome: With the improved facial reactions that have been introduced in 0.19, Jebediah Kerman can often be found gazing with almost childlike glee at the incredible sights around him. Many players are inclined to agree with him.
  • Yes-Man: Played with. No KSC worker bats an eye at the exploding machines of death you bring on to the launchpad, with the exception of some scientists, who will frequently stop and look at your rockets in horror before walking away in the VAB, regardless of how sound or unsound the design in question is.
  • You ALL Look Familiar: All Kerbonauts of a given gender have the exact same face and haircut, as well as the last name of "Kerman." Whether they're all clones, a family of Inexplicably Identical Individuals, or just members of a very homogenous species is a matter of some fan speculation. They aren't all perfectly identical, though, as they have individualized personalities determined by different levels of Bravery and Stupidity, as well as a hidden Pilot Training (or "BadS") flag.
  • You Can't Make A Mun Landing without blowing up a few rockets.
  • You Have Researched Breathing: Ladders and Thermometers are very high-end technology, as are support struts. It's okay however, you can get the science for it by finding out water is wet. Wheels come even later, along with command chairs, even though the basic command pod requires no research and presumably has a similar chair inside it. Lampshaded by the Flavor Text for the "Electrics" technology:
    Just for the record, we did know about electricty before rocketry. It's combining the two that's the big step forward!"