5 ms·

I was a little sad to learn that because KSP's orbital model uses conic sections, it's not physically accurate enough to model things like Lagrange points. Th

I was a little sad to learn that because KSP's orbital model uses conic sections, it's not physically accurate enough to model things like Lagrange points. Then I remembered that it's still accurate enough to be awesome and stopped worrying about it. :)

Coincoin 12y ago
As a matter of fact, I think that its simplicity is what makes KSP so fun to play. If it was real n-body orbital mechanics with real drag the game would quickly become much too complicated and tedious for casual play (and too slow).
- TeMPOraL 12y ago
  Yup. One of the Fun things that are less known that comes from n-body orbital mechanics is the instability of orbits. You can't just leave your satellite out there and fast-forward two years because you have an Eve mission going - your satellite needs to make correction burns as other bodies perturb its orbit. http://en.wikipedia.org/wiki/Orbital_station-keeping http://en.wikipedia.org/wiki/Orbital_station-keeping But anyway, I still hope that Principia mod (the n-body simulation addon mentioned elsewhere in this thread) will get released. This will really bring KSP into Dwarf Fortress level of enjoyment. Also, you'd get to make some really weird-ass stuff: http://images.scholarpedia.org/w/images/f/f6/NbodyChoreoGamma1Var.gif http://images.scholarpedia.org/w/images/f/f6/NbodyChoreoGamm... http://tuvalu.santafe.edu/~moore/crisscross123.loop.gif http://tuvalu.santafe.edu/~moore/crisscross123.loop.gif
- gohrt 12y ago
  For broader accessibility: a system like Civ's, where the system can play itself / do computations for you, but lets you dial up the amount of player-control.
  - TeMPOraL 12y ago
    You have MechJeb mod for that.
valarauca1 12y ago
Actually Newtonian Conic Sections is how we (humans) calculated orbital, and interplanetary trajectories up until the 1980's. There weren't powerful enough computers to model full Eisenstein N-Bodies Systems until actually very recently (also its complete over kill for inner-solar system travel). Relativity is really complex math, and even modern computer clusters struggle to model very complex systems. Yes we sent astronauts to the moon using KSP math.
- TeMPOraL 12y ago
  Thankfully, we only used KSP math, and not KSP engineering.
- titanomachy 12y ago
  Aren't Lagrange points present in Newton's model? Why would they be missing from the game?
  - Rumford 12y ago
    They're missing from KSP not merely because it uses Newtonian physics, but because it only uses two-body gravitational physics at any given time. The planets and moons are on rails and you are in only one gravity well at a time. Lagrange points exist in the intersections between two gravity wells.
- theothermkn 12y ago
  > Yes we sent astronauts to the moon using KSP math. I'm almost positive that we did not. While patched conics would have been used very early on for rough mission analysis and design, we had a very good understanding of perturbation theory at the time. Wikipedia tells me that the restricted 3-body problem was also essentially solved in 1917. I've seen very detailed plots of the free return trajectories that the Apollo missions followed, too. Using patched conics for the earth moon system would have resulted in an error on the scale of lunar escape velocity upon entering the sphere of influence of the Moon.
  - valarauca1 12y ago
Lutin 12y ago
Well if you're still interested in following the ongoing work to change that check out Principia :) http://forum.kerbalspaceprogram.com/threads/68502-WIP-Principia-N-Body-Gravitation-and-Better-Integrators-for-Kerbal-Space-Program http://forum.kerbalspaceprogram.com/threads/68502-WIP-Princi... https://github.com/mockingbirdnest/Principia https://github.com/mockingbirdnest/Principia
- titanomachy 12y ago
  I thought for a second you were facetiously referring to Philosophiae Naturalis Principia Mathematica... "hey, check out this cool new work on orbital mechanics" :P

Coincoin 12y ago

As a matter of fact, I think that its simplicity is what makes KSP so fun to play. If it was real n-body orbital mechanics with real drag the game would quickly become much too complicated and tedious for casual play (and too slow).

TeMPOraL 12y ago
Yup. One of the Fun things that are less known that comes from n-body orbital mechanics is the instability of orbits. You can't just leave your satellite out there and fast-forward two years because you have an Eve mission going - your satellite needs to make correction burns as other bodies perturb its orbit. http://en.wikipedia.org/wiki/Orbital_station-keeping http://en.wikipedia.org/wiki/Orbital_station-keeping But anyway, I still hope that Principia mod (the n-body simulation addon mentioned elsewhere in this thread) will get released. This will really bring KSP into Dwarf Fortress level of enjoyment. Also, you'd get to make some really weird-ass stuff: http://images.scholarpedia.org/w/images/f/f6/NbodyChoreoGamma1Var.gif http://images.scholarpedia.org/w/images/f/f6/NbodyChoreoGamm... http://tuvalu.santafe.edu/~moore/crisscross123.loop.gif http://tuvalu.santafe.edu/~moore/crisscross123.loop.gif
gohrt 12y ago
For broader accessibility: a system like Civ's, where the system can play itself / do computations for you, but lets you dial up the amount of player-control.
- TeMPOraL 12y ago
  You have MechJeb mod for that.

valarauca1 12y ago

Actually Newtonian Conic Sections is how we (humans) calculated orbital, and interplanetary trajectories up until the 1980's. There weren't powerful enough computers to model full Eisenstein N-Bodies Systems until actually very recently (also its complete over kill for inner-solar system travel). Relativity is really complex math, and even modern computer clusters struggle to model very complex systems. Yes we sent astronauts to the moon using KSP math.

TeMPOraL 12y ago
Thankfully, we only used KSP math, and not KSP engineering.
titanomachy 12y ago
Aren't Lagrange points present in Newton's model? Why would they be missing from the game?
- Rumford 12y ago
  They're missing from KSP not merely because it uses Newtonian physics, but because it only uses two-body gravitational physics at any given time. The planets and moons are on rails and you are in only one gravity well at a time. Lagrange points exist in the intersections between two gravity wells.
theothermkn 12y ago
> Yes we sent astronauts to the moon using KSP math. I'm almost positive that we did not. While patched conics would have been used very early on for rough mission analysis and design, we had a very good understanding of perturbation theory at the time. Wikipedia tells me that the restricted 3-body problem was also essentially solved in 1917. I've seen very detailed plots of the free return trajectories that the Apollo missions followed, too. Using patched conics for the earth moon system would have resulted in an error on the scale of lunar escape velocity upon entering the sphere of influence of the Moon.
- valarauca1 12y ago

Lutin 12y ago

Well if you're still interested in following the ongoing work to change that check out Principia :) http://forum.kerbalspaceprogram.com/threads/68502-WIP-Principia-N-Body-Gravitation-and-Better-Integrators-for-Kerbal-Space-Program http://forum.kerbalspaceprogram.com/threads/68502-WIP-Princi... https://github.com/mockingbirdnest/Principia https://github.com/mockingbirdnest/Principia

titanomachy 12y ago
I thought for a second you were facetiously referring to Philosophiae Naturalis Principia Mathematica... "hey, check out this cool new work on orbital mechanics" :P