EquidistantOrbitPlanner.r

# EquidistantOrbitPlanner.r

# Input parameters
numberOfSatsInOrbit         = 4
targetedSurfaceAltitudeKM   = 1000          # Input in kilometers, since that's how you'll see it in KSP.
celestialBodyName           = "Kerbin"
insertionOrbitLongOrShort   = "short"       # long inserts you behind the previous position in the orbit, and short inserts you ahead of it.

# Start
kspConstsDataFrame  = read.table("~/Documents/Code/R/KSP Calculations/KSPConstants.txt")
kspConstsMatrix     = as.matrix(kspConstsDataFrame)
celestialBodyIndex  = which(colnames(kspConstsMatrix)==celestialBodyName)
objectRadiusIndex   = which(rownames(kspConstsMatrix)=="radius")
objectRadius        = as.real(kspConstsMatrix[objectRadiusIndex,celestialBodyIndex])
gravParamIndex      = which(rownames(kspConstsMatrix)=="gravitationalParameter")
gravParam           = as.real(kspConstsMatrix[gravParamIndex,celestialBodyIndex])
if(insertionOrbitLongOrShort == "short"){
    insertionOrbitSign = -1
}else{
    insertionOrbitSign = 1
}

# Calaculate insertion orbit's apoapsis-altitude for desired the targeted circular orbit.
targetedSurfaceAltitude                 = targetedSurfaceAltitudeKM * 1000
targetCoreAltitude                      = targetedSurfaceAltitude + objectRadius
targetOrbitalPeriod                     = 2*pi*sqrt((targetCoreAltitude^3)/gravParam)   # aka, period of the circular orbit
insertionOrbitPeriod                    = (((numberOfSatsInOrbit + insertionOrbitSign) / numberOfSatsInOrbit)) * targetOrbitalPeriod
insertionOrbitSemimajorAxis             = (gravParam*(insertionOrbitPeriod/(2*pi))^2)^(1/3)
insertionOrbitApoapsisCoreAltitude      = (2*insertionOrbitSemimajorAxis-targetCoreAltitude)    # circular altitude ideally is equal to periapsis
insertionOrbitApoapsisSurfaceAltitude   = insertionOrbitApoapsisCoreAltitude - objectRadius
insertionOrbitApoapsisSurfaceAltitudeKM = insertionOrbitApoapsisSurfaceAltitude/1000

# Output
sprintf("Insertion orbit's apoapsis altitude:  %f (km)",    insertionOrbitApoapsisSurfaceAltitudeKM)
sprintf("Insertion orbit's period:  %f (s)  or %f (hr)",    insertionOrbitPeriod, insertionOrbitPeriod/3600)
sprintf("Target orbit's period:  %f (s)  or %f (hr)",       targetOrbitalPeriod, targetOrbitalPeriod/3600)