public static double HeadingForLaunchInclination(CelestialBody body, double inclinationDegrees, double latitudeDegrees, double orbVel)
{
double cosDesiredSurfaceAngle = Math.Cos(inclinationDegrees * MathExtensions.Deg2Rad) / Math.Cos(latitudeDegrees * MathExtensions.Deg2Rad);
if (Math.Abs(cosDesiredSurfaceAngle) > 1.0)
{
//If inclination < latitude, we get this case: the desired inclination is impossible
if (Math.Abs(MuUtils.ClampDegrees180(inclinationDegrees)) < 90)
{
return(90);
}
else
{
return(270);
}
}
else
{
double betaFixed = Math.Asin(cosDesiredSurfaceAngle);
double velLaunchSite = body.Radius * body.angularVelocity.magnitude * Math.Cos(latitudeDegrees * MathExtensions.Deg2Rad);
double vx = orbVel * Math.Sin(betaFixed) - velLaunchSite;
double vy = orbVel * Math.Cos(betaFixed);
double angle = MathExtensions.Rad2Deg * Math.Atan(vx / vy);
if (inclinationDegrees < 0)
{
angle = 180 - angle;
}
return(MuUtils.ClampDegrees360(angle));
}
}
//Returns whether o has a descending node with the equator. This can be false
//if o is hyperbolic and the would-be descending node is within the opening
//angle of the hyperbola.
public static bool DescendingNodeEquatorialExists(this Orbit o)
{
return(Math.Abs(MuUtils.ClampDegrees180(o.DescendingNodeEquatorialTrueAnomaly())) <= o.MaximumTrueAnomaly());
}
//Returns whether a has a descending node with b. This can be false
//if a is hyperbolic and the would-be descending node is within the opening
//angle of the hyperbola.
public static bool DescendingNodeExists(this Orbit a, Orbit b)
{
return(Math.Abs(MuUtils.ClampDegrees180(a.DescendingNodeTrueAnomaly(b))) <= a.MaximumTrueAnomaly());
}