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Generally speaking, how realistic and accurate is the game compared to real life in designing vehicles for travel in space? 

I know this sounds like a dumb question and I know there are funny little characters as Kerbal people but I've just gotten started as an approach to better understanding our space programs through the years beginning in 1957

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Welcome to the forum @truckmen, the stock game is highly simplified in all aspects. There are mods that make the game way more realistic but if you are new to KSP the stock game is where you learn the basic rules of design and flight. Also, there's no such thing as a dumb question when it comes to KSP.

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To elaborate somewhat on @James Kerman's response:

The stock (un-modded) game simplifies quite a few things compared to real life. Off the top of my head:

  • The Kerbal home system is 1/10th the scale of our solar system, with planetary densities adjusted to get similar surface gravity to our solar system. This means that the delta-v (how "distance" is measured in the wonky world of orbital mechanics) required to go from anywhere to anywhere is roughly half to a third of what it would be if the Kerbal system were at a realistic scale.
  • To compensate for the above, all the parts (tanks, engines, etc.) in KSP are much heavier than their real-world counterparts. There's a running joke around here that, instead of using aluminum and carbon composites, Kerbals build their rockets out of lead and rebar. This makes Kerbal rockets less performant than real-life rockets, which partially offsets the sub-scale solar system.
  • The orbital mechanics themselves are simplified somewhat compared to real life. KSP makes use of something called patched conic approximation - basically, you assume that the ship you're plotting a course for is only affected by the gravity of one body at a time. This assumption is accurate 99% of the time, but you lose out on some fun N-body interactions (for example, Lagrange points).
  • The aerodynamics aren't so much simplified as modeled in a way that produces odd results sometimes. Aerodynamic forces are modeled on a per-part basis (instead of over the entire vessel as a cohesive unit) with some heuristics for occlusion tacked on to make lift and drag behave more or less as you'd expect.
  • There's no life support, and Kerbals are perfectly happy to spend 50 years in a space suit strapped to a chair on the side of a rocket.
  • All rocket engines in KSP can be started instantly, shut down instantly, throttled anywhere from 0% to 100%, and restarted an infinite number of times in any conditions. The same is definitely not true of real rocket engines.
  • There's no light-speed delay when controlling probes in deep space over a radio connection.
  • Structural failure due to aerodynamic heating is all-or-nothing. Or, in other words, KSP doesn't model the way the strength of a material changes with temperature - it just makes parts explode when they get above some threshold temperature.
  • Batteries are modeled as tanks that hold electricity.
  • A few parts have stats that are even more off than usual. The worst offender is the Dawn ion thruster, whose thrust is ~1,000x what it would be in real life.

It's a long list, and I definitely left some stuff off. But don't let it dissuade you from playing the game. "Easier than real life rocket science" does not imply "easy". The simplifications aren't there to make the game easy for new players - they're there to make the game playable at all for new players. And, if you're looking to learn something in the process, the stock game has plenty to teach about the broad strokes of rocket design and orbital mechanics, even if it might fudge the fine details in the name of playability.

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Welcome to the KSP forum @truckmen  Wow every one up above that left comments are so correct. Man I have learned so much about space flight due to ksp its amazing. I was into it years before this as well. I am new here myself with the forum since the end of last year, but yea so much fun with KSP. So glad you have joined us in this awesome journey. Have fun! 

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It should be noted that while compared to reality KSP suffers many faults, compared to pretty much any other video game it's very realistic.

I'm not saying anything I'm just saying, nobody dings Elite on number of engine restarts or how well electricity is modeled.

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For the record, I think that real life has its faults, too. I would love an F5/F9 option for my current IRL career mode, but the devs haven't patched that in yet.

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There's less powerpoints and safety reviews in KSP. And in KSP, it's very simple to put an engine on your rocket, when in real life every little bolt and pipe on that thing is carefully calculated based on its tradeoffs and has a specific reason for being there.

I'm on a university team that makes real rocket engines, and our current project is an engine about twice as powerful as the smallest engine in KSP. We have to deal with multiple valves and high pressures throughout the system, and we have electronics and code for sensors and automating the firing sequence. We have a justification for every part we buy, and we buy a lot of parts. We will do a lot of testing before we ever attempt to ignite it, to be absolutely sure that all the hundreds of parts are working and will be safe to use. Then we have to present to a board responsible for the test site to show them that we know what we're doing and we're ready, so that they'll let us use their facility. All of this and more goes into a single part in KSP that you just drag onto the bottom of your rocket and it just works, maybe after purchasing it for a few science points.

KSP takes all of that, and condenses it down into a basic version of the same processes of design, testing, and flying that will still teach you a great deal about what the real thing is like. 

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