areyla

Atmospheric reentry is actually a very difficult problem. It\'s a real balance between 'reality' and a 'fun game.' At the speeds a craft enters the atmosphere you get extremely high mach number gas flows. This results in not-so-simple calculations to do. You would say, yes drag or air-friction would create so much heat that needs to be dissipated by radiation or convection behind some mach cone at some distant from the capsule. This already requires gas compressibility calculations not to mention characterizing the planetary atmosphere beyond what I believe they have implemented. But it gets worse, because the temperatures are so high, rare species of molecules start to form and reduce the amount of heating actually predicted. Give them time - it seems like they\'ll make an approximation.

You guys seem to be in the know. I\'ve been starting to play, and I had a few questions. What gravity model does Kerbin have - similar to WGS84? Newtonian? Does Kerbin orbit Kerbol elliptically (same question for Mun and Kerbin)? Does KSP take into account center of gravity / center of mass differences for orbit attitude dynamics and control? What velocity does the speed indicator measure - is there an inertial frame of reference? Does everything lie in an 'ecliptic' or are there out of plane orbits for celestial bodies too? I personally think N-body physics would be cool for KSP - although extremely difficult. You can add Lissajous and Lyapunov orbits and many other 'cool' orbital mechanical phenomena. Some of you say there is no solution to the N-body problem as if it were impossible to work with. There exists simulations for specific circumstances of the n-body problem - solutions if you will. There just isn\'t a global solution like in the 2-body case -> elliptical orbits, patched conics. Lissajous orbits I don\'t seem to see it addressed, but for a 2-body problem the solutions are planar, yes. But for n-body (3+) problems you start to get non-planar behavior. When considering the Jacobi for your body you get key-hole behaviors which become important when you have limited propellant. http://svs.gsfc.nasa.gov/vis/a010000/a010600/a010636/ The artemis program took advantage of a lot of n-body problem dynamics to reach the moon from earth orbit on low propellant. As you can see - at the right distances the n-body solution differs dramatically from 'patched conics' simply because 2 bodies cannot give you the same behavior. You even start to get solutions where the orbits are 'pseudo periodic' in that a single velocity component returns to zero but the orbit never physically passes through the same point in space, it traverses a surface. I\'m not sure but the SAS seems to take care of much of the orbital stability (attitude-wise), but for a real body decays in attitude lead to decays in orbital behavior (the two are coupled behaviors). Has anyone played with attitude behaviors in KSP? Thanks for reading -Areyla