SimpleKSPOrbitalMechanics0.001

-- SimpleKSPOrbitalMechanics is a purely calculation based lua library, with some constants hardcoded for Kerbal Space Program
-- v0.001
-- to use, put
-- require "SimpleKSPOrbitalMechanics"
-- in your lua script, or run it with
-- dofile("SimpleKSPOrbitalMechanics")
-- Original Work Copyright 2012, Nadrek, insofar as any elements that aren't obvious, trivial, or mathematics are concerned (none of which are copyrightable)
-- licensed under your choice of GPLv2, GPLv3, or Creative Commons Attribution-ShareAlike 3.0 Unported (CC BY-SA 3.0)  http://www.gnu.org/licenses/gpl-2.0.html  or  http://www.gnu.org/licenses/gpl.html  or  http://creativecommons.org/licenses/by-sa/3.0/
-- KSP specific functions will have KSP in the name; other functions will not, and can be used for real life calculations as well.


-- This script requires SimpleOrbitalMechanics to do the heavy mathematical lifting.
-- This script contains KSP specific functions and calls useful to and reliant on Kerbal Space Program, MechJeb, and MechJeb's Autom8 module.

require "SimpleOrbitalMechanics"

function globalSkomKSPMainBodyResetBasedOnGuessing()
  -- prints body it guessed
  -- also sets the globalMainBody... variables to that body (or all to -1
  --   if the body is UNKNOWN)
  -- Essentially, this function, if called while in orbit around a given body (like the Mun, or Kerbin)
  --   sets some "background" variables so the rest of the functions know how to act based on what
  --   you're orbiting; you use different values for the Min and for Kerbin, because Kerbin is bigger,
  --   has more gravity, has an atmosphere, and has a much larger Hill sphere of influence.
  -- NOTE: Landed, on the launchpad, in ascent, in descent all count as being "in orbit"!
  -- no return value
  local GuessedMainBody = guessSkomKSPWhatBodyIsTheMainBodyCurrentlyBeingOrbited()
  globalSomMainBodyReset(GuessedMainBody)
  print GuessedMainBody
end


function guessSkomKSPWhatBodyIsTheMainBodyCurrentlyBeingOrbited()
  -- returns the SimpleOrbitalMechanics name of the body we think we're orbiting.
  --   suitable to pass to globalSomMainBodyReset, or returns UNKNOWN if it cannot tell
  --[[ Ex:
    print(guessSkomKSPWhatBodyIsTheMainBodyCurrentlyBeingOrbited())
    ]]
  -- NOTE: All warnings and notes for guessSomWhatBodyIsTheMainBodyFromaOvAltaslMoe apply.
  return guessSomWhatBodyIsTheMainBodyFromaOvAltaslMoe(vessel.orbitSemiMajorAxis, vessel.speedOrbital, vessel.altitudeASL, 0.01)
end


function calcSkomMolniyaApPeFromMainBodyCurrentlyBeingOrbitedFromMoe(MarginOfError)
  -- MarginOfError 0.001 means allow 0.1% for a "safety zone" above the minimum stable altitude, or below the Hill sphere of influence.
  --   Do this if you want to just barely scrape by!
  --   2 means allow a 200% "safety zone" above the minimum stable altitude, or below the Hill sphere of influence.
  --   Do this if you want to have a much less eccentric orbit - perhaps you want to keep certain orbits clear for other uses!
  --   If in doubt, try setting MarginOfError to 0.1
  -- Returns Ap and Pe of the best possible Molniya orbit for a given body
  --   Returns -1, -1 if no stable Molniya orbit is possible
  -- REQUIRES globalSomMainBodyReset to have been called properly
  --   the simple way is to run globalSkomKSPMainBodyResetBasedOnGuessing() first!
  --[[ Ex:
    do
    local localAp, localPe = calcSkomMolniyaApPeFromMainBodyCurrentlyBeingOrbitedFromMoe(0.1)
    print("Your Apoapsis should be " .. localAp .. " meters and your Periapsis should be " .. localPe .. " meters")
    print("  For a classical Molniya orbit, use an inclination of 63.4, 116.6, -63.4, or -116.6")
    print("  These values are chosen because oblate planets (like the Earth's fat equatorial bulge")
    print("  would change your orbit with other inclinations, since the planet isn't a sphere")
    end
    ]]
  -- For oblate celestial bodies, of course, the inclination of the actual orbit must be 63.4 or 116.6 degrees, so the effect of the oblate equitorial belt is nullified.

  -- Now we call our standard Molniya calculator, and pass in numbers based on the celestial body we claim we're currently in orbit of!
  return calcSomMolniyaApPeFromHsoiMsaMbrGmSrpMoe(globalSomMainBodyHillSphereOfInfluence, globalSomMainBodyMinStableAltitude, globalSomMainBodyEquatorialRadius, globalSomMainBodyGM, globalSomMainBodySiderealRotationalPeriod, MarginOfError)

end



function printSkomKSPCurrentOrbitalElements()
  print("orbitApA " .. vessel.orbitApA)
  print("orbitPeA " .. vessel.orbitPeA)
  print("orbitPeriod " .. vessel.orbitPeriod)
  print("orbitTimeToAp " .. vessel.orbitTimeToAp)
  print("orbitTimeToPe " .. vessel.orbitTimeToPe)
  print("orbitLAN (RA/Long of Ascending Node) " .. vessel.orbitLAN)
  print("orbitArgumentOfPeriapsis " .. vessel.orbitArgumentOfPeriapsis)
  print("orbitInclination " .. vessel.orbitInclination)
  print("orbitEccentricity " .. vessel.orbitEccentricity)
  print("orbitSemiMajorAxis (a) " .. vessel.orbitSemiMajorAxis)
  print("speedOrbital " .. vessel.speedOrbital)
  print("speedSurface " .. vessel.speedSurface)
  print("speedVertical " .. vessel.speedVertical)
  print("speedHorizontal " .. vessel.speedHorizontal)
  print("altitudeASL " .. vessel.altitudeASL)
  print("altitudeTrue " .. vessel.altitudeTrue)
  print("altitudeBottom " .. vessel.altitudeBottom)
  print("latitude " .. vessel.latitude)
  print("longitude " .. vessel.longitude)
  print("time " .. vessel.time)
end


function helpSkomSimpleKSPOrbitalMechanics()
  print "Usage: globalSkomKSPMainBodyResetBasedOnGuessing()"
  print "   prints body it guessed"
  print "   also sets the globalMainBody... variables to that body (or all to -1"
  print "     if the body is UNKNOWN)"
  print "   Essentially, this function, if called while in orbit around a given body (like the Mun, or Kerbin)"
  print "     sets some \"background\" variables so the rest of the functions know how to act based on what"
  print "     you're orbiting; you use different values for the Min and for Kerbin, because Kerbin is bigger,"
  print "     has more gravity, has an atmosphere, and has a much larger Hill sphere of influence."
  print "   NOTE: Landed, on the launchpad, in ascent, in descent, and crashing all count as being \"in orbit\"!"
  print "   no return value"
  print "Usage: guessSkomKSPWhatBodyIsTheMainBodyCurrentlyBeingOrbited()"
  print "   returns the SimpleOrbitalMechanics name of the body we think we're orbiting."
  print "   suitable to pass to globalSomMainBodyReset, or returns UNKNOWN if it cannot tell."
  print "   Ex:"
  print "     print(guessSkomKSPWhatBodyIsTheMainBodyCurrentlyBeingOrbited())"
  print "Usage: calcSkomMolniyaApPeFromMainBodyCurrentlyBeingOrbitedFromMoe(MarginOfError)"
  print "   MarginOfError 0.001 means allow 0.1% for a \"safety zone\" above the minimum stable altitude, or below the Hill sphere of influence."
  print "     Do this if you want to just barely scrape by!"
  print "     2 means allow a 200% \"safety zone\" above the minimum stable altitude, or below the Hill sphere of influence."
  print "     Do this if you want to have a much less eccentric orbit - perhaps you want to keep certain orbits clear for other uses!"
  print "     If in doubt, try setting MarginOfError to 0.1"
  print "   Returns Ap and Pe of the best possible Molniya orbit for a given body"
  print "     Returns -1, -1 if no stable Molniya orbit is possible"
  print "   REQUIRES globalSomMainBodyReset to have been called properly"
  print "     the simple way is to run globalSkomKSPMainBodyResetBasedOnGuessing() first!"
  print "   Ex:"
  print "     do"
  print "     local localAp, localPe = calcSkomMolniyaApPeFromMainBodyCurrentlyBeingOrbitedFromMoe(0.1)"
  print "     print(\"Your Apoapsis should be \" .. localAp .. \" meters and your Periapsis should be \" .. localPe .. \" meters\")"
  print "     print(\"  For a classical Molniya orbit, use an inclination of 63.4, 116.6, -63.4, or -116.6\")"
  print "     print(\"  These values are chosen because oblate planets (like the Earth's fat equatorial bulge\")"
  print "     print(\"  would change your orbit with other inclinations, since the planet isn't a sphere\")"
  print "     end"
  print "   For oblate celestial bodies, of course, the inclination of the actual orbit must be 63.4 or 116.6 degrees, so the effect of the oblate equitorial belt is nullified."
  print "Usage: printSkomKSPCurrentOrbitalElements()"
  print "   Prints important KSP elements for human use or records"

end

globalSkomKSPMainBodyResetBasedOnGuessing() -- initalize main body dependent variables based on guessing what body we're orbiting.

print "Usage: helpSkomSimpleKSPOrbitalMechanics() gives detailed help on all Skom functions."
print "   Skom functions relate to Kerbal Space Program (KSP) specific functionality."
print("If it helps, I'm guessing you are currently orbiting " .. globalSomMainBodyName)