/// <summary>
/// Computes the transfer with the moon on the +X axis without accounting for the moon motion during
/// transit. (That is accounted for in the ExecuteTransfer routine).
///
/// This allows a co-rotating visualization of the orbit.
/// </summary>
/// <returns></returns>
private Vector3 ComputeTransfer()
{
OrbitData shipOrbit = new OrbitData();
shipOrbit.SetOrbitForVelocity(spaceship, planet);
// compute the min energy path (this will be in the short path direction)
lambertU = new LambertUniversal(shipOrbit, startPoint, targetPoint, shortPath);
// apply any time of flight change
double t_flight = tflightFactor * lambertU.GetTMin();
bool reverse = !shortPath;
const bool df = false;
const int nrev = 0;
int error = lambertU.ComputeXfer(reverse, df, nrev, t_flight);
if (error != 0)
{
Debug.LogWarning("Lambert failed to find solution.");
aroundMoonSegment.gameObject.SetActive(false);
return(Vector3.zero);
}
// Check Lambert is going in the correct direction
Vector3 shipOrbitAxis = Vector3.Cross(ge.GetVelocity(spaceship), ge.GetPhysicsPosition(spaceship)).normalized;
Vector3 tliOrbitAxis = Vector3.Cross(lambertU.GetTransferVelocity(), startPoint.ToVector3());
if (Vector3.Dot(shipOrbitAxis, tliOrbitAxis) < 0)
{
error = lambertU.ComputeXfer(!reverse, df, nrev, t_flight);
if (error != 0)
{
Debug.LogWarning("Lambert failed to find solution for reverse path. error=" + error);
return(Vector3.zero);
}
}
Vector3 tliVelocity = lambertU.GetTransferVelocity();
toMoonOrbit.SetVelocity(tliVelocity);
toMoonSegment.SetVelocity(tliVelocity);
aroundMoonSegment.gameObject.SetActive(true);
// Set velocity for orbit around moon
Vector3 soiEnterVel = lambertU.GetFinalVelocity();
aroundMoonSegment.SetVelocity(soiEnterVel);
// update shipEnterSOI object
ge.UpdatePositionAndVelocity(shipEnterSOI, targetPoint.ToVector3(), soiEnterVel);
// Find the orbit around the moon. By using the mirror position we're assuming it's
// a hyperbola (since there is no course correction at SOI this is true).
// (Moon is in correct position for these calcs so can use world positions, relativePos=false)
Vector3d soiEnterV = new Vector3d(lambertU.GetFinalVelocity());
OrbitUtils.OrbitElements oe = OrbitUtils.RVtoCOE(targetPoint, soiEnterV, moonBody, false);
Vector3d soiExitR = new Vector3d();
Vector3d soiExitV = new Vector3d();
OrbitUtils.COEtoRVMirror(oe, moonBody, ref soiExitR, ref soiExitV, false);
// Set position and vel for exit ship, so exit orbit predictor can run. Moon offset/vel already added.
ge.SetPositionDoubleV3(shipExitSOI, soiExitR);
ge.SetVelocityDoubleV3(shipExitSOI, soiExitV);
aroundMoonSegment.UpdateOrbit();
return(tliVelocity);
}