The solar system of KSP is a lot smaller in scale, the home planet is just 600 km and the atmosphere is 70 km thick. Liftoff to orbit takes just a few minutes (instead of 8-10 min) and a full orbit is about 30 min (instead of 90 min for LEO).
KSP mods can add a level of realism and add more "scientific" tools to the game. "Kerbal Engineer" is a must-have addon because it adds some numeric data about the orbit that the game developers have intentionally left out (a decision I disagree with). MechJeb is a popular addon that adds all sorts of automation, similar to some Orbiter MFD modes. There are also mods to use the real solar system (in real scale) instead of the fictional universe.
But no, overall, KSP is not nearly as realistic as Orbiter is. However, making any comparisons is pretty useless - they are both really fun games with a different emphasis and I play them both regularly.
Slightly non-spherical gravitational fields don't matter too much unless you're doing a lot of orbits.
Actually the effects of non spherical gravity is one or two orders of magnitude greater than the influence of all the other bodies in the solar system combined for low earth orbit satellite operations. It has a huge effect, causing a rotation of the orbital plane several degrees per day (up to 10 or so).
The effect isn't as great for lunar or interplanetary trajectories, though.
No.
2 body dynamics can be predicted from initial conditions to an arbitrary time any time in the past or the future. N-body dynamics have to be numerically integrated timestep by timestep.
But simulating n-body dynamics is not difficult or computationally expensive. Two things to understand: n is a very small number, around 20, the number of planets and moons in the solar system. And we're only interested in the restricted n-body problem, ie. movement of one massless particle (the spacecraft) in the gravity field of the planets and moons, so it's O(n) complexity, not O(n^2).
Ultimately this was a game design decision.
> Or why wouldn't they compute based on the top N nearest-biggest objects?
For such a small number of bodies, this wouldn't save any time but would add a lot of complexity.
On the other hand, KSP's trajectory planning UI is way, way more intuitive than anything I've seen for Orbiter, albeit not quite as automated or flexible.
Patched conics techniques are mission planning methods that provide semi-analytical solution to lunar and interplanetary trajectories and help searching for launch windows and planning outbound maneuvers. It's a rather crude approximation for real world use, but it gives good initial values to be used for more sophisticated (and computationally expensive) methods.
This mission planning utility for KSP implements the patched conic algorithms: http://ksp.olex.biz/
Once you find a launch window, you can use that as a starting point for a more fancy method such as this: https://alexmoon.github.io/ksp/ (this implements "pork chop plots" or solves the two body boundary value problem, also known as the Lambert or Gauss problem)
For real life (or Orbiter) use, the next step would be to numerically integrate the entire trajectory in a restricted n-body setup.
For more information, see: Carlson, K. M. "An Analytical Solution to Patched Conic Trajectories Satisfying Initial and Final Boundary Conditions" http://ntrs.nasa.gov/search.jsp?R=19710007291&qs=Ns=Loaded-D... (NASA has made this NTRS paper available again, I tried real hard to find it a few years ago because it was temporarily but intentionally offline)
> Orbital docking dynamics are weird
This is simulated well enough.
> One amusing anecdote is for an inclination change greater than 60 degrees or so, its cheaper to land and take off again or go on a very high orbit into deep space and change your inclination there.
Yeap. KSP players are well acquainted with that.
Also, it can be cheaper to use the moon to perform inclination change maneuvers. It was even done in real life: http://www.nytimes.com/1998/04/30/us/trying-to-save-satellit...
That maneuver is, oddly enough, patented.
Said 10-year old won't be able to plot a real trajectory for a rocket/satellite, but giving a 10-year old an intuitive understanding of inclination changes, gravity slingshots, Hohmann transfers, etc. is an amazing feat by itself.
By default, yes, it's pretty comical. But that's where mods come in. The modding community for KSP is huge, and there's a large set of mods that aim for higher realism (for example: overhauling the atmospheric flight model to add realism; adding the need for life support; adding the need for a satellite network to enable communication with Kerbin). There's a pack of mods called Realism Overhaul that does those things and a lot more.
[1] https://itunes.apple.com/us/app/mission-orion/id879837704?mt...
No, it's the most realistic game about spaceflight, but it's not a simulator.
http://orbit.medphys.ucl.ac.uk/
Its interesting to look at the MFD design for mission planning as an applied version of the linked page.
I have not played much KSP, is there anything as realistic as orbiter? From what little I've seen it tended toward comical set of pants, like comparing ChopperLifter to MS flight sim.
Orbital docking dynamics are weird. If you undock from the ISS and thrust up a little bit, in half an orbit you'll come right back. Increasing or reducing your speed along the orbit (moving front or back) will eventually affect your altitude. Docking isn't as simple as "if you wanna go forward, thrust forward". All the control mix; like hovering a helicopter but slower. Flying "in formation" can be very expensive in terms of fuel depending on the formation, or it can be free if in a favorable geometry. There is a classic very hard sci fi story along the lines of extorting someone who doesn't know orbital mechanics by literally throwing them off a space station, and the victim panics not knowing he'll be back in half an orbit seeing as escape velocity is a little faster than a human shove!
One amusing anecdote is for an inclination change greater than 60 degrees or so, its cheaper to land and take off again or go on a very high orbit into deep space and change your inclination there. The ISS is at a very high inclination and at least energetically, to put the thing into a GTO around inclination 0 or so, it would be cheaper to land and re-launch the thing.