public List <ManeuverParameters> OptimizeEjection(double UT_transfer, Orbit initial_orbit, Orbit target, CelestialBody target_body, double UT_arrival, double earliest_UT, double target_PeR, bool includeCaptureBurn)
{
int N = 0;
List <ManeuverParameters> NodeList = new List <ManeuverParameters>();
while (true)
{
const double DIFFSTEP = 1e-6;
const double EPSX = 1e-9;
const int MAXITS = 100;
alglib.minlmstate state;
alglib.minlmreport rep;
double[] x = new double[3];
double[] scale = new double[3];
Vector3d exitDV, captureDV;
CalcLambertDVs(UT_transfer, UT_arrival - UT_transfer, out exitDV, out captureDV);
Orbit source = initial_orbit.referenceBody.orbit; // helicentric orbit of the source planet
// helicentric transfer orbit
Orbit transfer_orbit = new Orbit();
transfer_orbit.UpdateFromStateVectors(source.getRelativePositionAtUT(UT_transfer), source.getOrbitalVelocityAtUT(UT_transfer) + exitDV, source.referenceBody, UT_transfer);
double UT_SOI_exit;
OrbitalManeuverCalculator.SOI_intercept(transfer_orbit, initial_orbit.referenceBody, UT_transfer, UT_arrival, out UT_SOI_exit);
// convert from heliocentric to body centered velocity
Vector3d Vsoi = transfer_orbit.getOrbitalVelocityAtUT(UT_SOI_exit) - initial_orbit.referenceBody.orbit.getOrbitalVelocityAtUT(UT_SOI_exit);
// find the magnitude of Vinf from energy
double Vsoi_mag = Vsoi.magnitude;
double E_h = Vsoi_mag * Vsoi_mag / 2 - initial_orbit.referenceBody.gravParameter / initial_orbit.referenceBody.sphereOfInfluence;
double Vinf_mag = Math.Sqrt(2 * E_h);
// scale Vsoi by the Vinf magnitude (this is now the Vinf target that will yield Vsoi at the SOI interface, but in the Vsoi direction)
Vector3d Vinf = Vsoi / Vsoi.magnitude * Vinf_mag;
// using Vsoi seems to work slightly better here than the Vinf from the heliocentric computation at UT_Transfer
//ManeuverParameters maneuver = ComputeEjectionManeuver(Vsoi, initial_orbit, UT_transfer, true);
ManeuverParameters maneuver = ComputeEjectionManeuver(Vinf, initial_orbit, UT_transfer, true);
//
// common setup for the optimization problems
//
x[0] = maneuver.dV.x;
x[1] = maneuver.dV.y;
x[2] = maneuver.dV.z;
UT_transfer = maneuver.UT;
scale[0] = scale[1] = scale[2] = 1000.0f;
//
// initial patched conic shooting to precisely hit the target
//
const int ZEROMISSCONS = 3;
double[] fi = new double[ZEROMISSCONS];
zeroMissObjectiveFunction(x, fi, null, initial_orbit, target_body, UT_transfer, UT_arrival);
Debug.Log("zero miss phase before optimization = " + new Vector3d(fi[0], fi[1], fi[2]).magnitude + " m (" + new Vector3d(x[0], x[1], x[2]).magnitude + " m/s)");
alglib.minlmcreatev(3, ZEROMISSCONS, x, DIFFSTEP, out state);
alglib.minlmsetcond(state, EPSX, MAXITS);
alglib.minlmsetscale(state, scale);
alglib.minlmoptimize(state, (x, fi, obj) => zeroMissObjectiveFunction(x, fi, obj, initial_orbit, target_body, UT_transfer, UT_arrival), null, null);
alglib.minlmresults(state, out x, out rep);
zeroMissObjectiveFunction(x, fi, null, initial_orbit, target_body, UT_transfer, UT_arrival);
Debug.Log("zero miss phase after optimization = " + new Vector3d(fi[0], fi[1], fi[2]).magnitude + " m (" + new Vector3d(x[0], x[1], x[2]).magnitude + " m/s)");
Debug.Log("Transfer calculator: termination type=" + rep.terminationtype);
Debug.Log("Transfer calculator: iteration count=" + rep.iterationscount);
//
// Fine tuning of the periapsis
//
bool failed = false;
if (target_PeR > 0)
{
const int PERIAPSISCONS = 1;
double[] fi2 = new double[PERIAPSISCONS];
periapsisObjectiveFunction(x, fi2, null, initial_orbit, target_body, UT_transfer, UT_arrival, target_PeR, ref failed);
Debug.Log("periapsis phase before optimization = " + fi2[0] + " m (" + new Vector3d(x[0], x[1], x[2]).magnitude + " m/s)");
alglib.minlmcreatev(3, PERIAPSISCONS, x, DIFFSTEP, out state);
alglib.minlmsetcond(state, EPSX, MAXITS);
alglib.minlmsetscale(state, scale);
alglib.minlmoptimize(state, (x, fi, obj) => periapsisObjectiveFunction(x, fi, obj, initial_orbit, target_body, UT_transfer, UT_arrival, target_PeR, ref failed), null, null);
alglib.minlmresults(state, out x, out rep);
periapsisObjectiveFunction(x, fi2, null, initial_orbit, target_body, UT_transfer, UT_arrival, target_PeR, ref failed);
Debug.Log("periapsis phase after optimization = " + fi2[0] + " m (" + new Vector3d(x[0], x[1], x[2]).magnitude + " m/s)");
Debug.Log("Transfer calculator: termination type=" + rep.terminationtype);
Debug.Log("Transfer calculator: iteration count=" + rep.iterationscount);
}
maneuver.dV.x = x[0];
maneuver.dV.y = x[1];
maneuver.dV.z = x[2];
//
// exit conditions and error handling
//
// try again if we failed to intersect the target orbit
if (failed)
{
Debug.Log("Failed to intersect target orbit");
}
// try again in one orbit if the maneuver node is in the past
else if (maneuver.UT < earliest_UT || failed)
{
Debug.Log("Transfer calculator: maneuver is " + (earliest_UT - maneuver.UT) + " s too early, trying again in " + initial_orbit.period + " s");
UT_transfer += initial_orbit.period;
}
else
{
Debug.Log("from optimizer DV = " + maneuver.dV + " t = " + maneuver.UT + " original arrival = " + UT_arrival);
NodeList.Add(maneuver);
break;
}
if (N++ > 10)
{
throw new OperationException("Ejection Optimization failed; try manual selection");
}
}
if (NodeList.Count > 0 && target_PeR > 0 && includeCaptureBurn)
{
// calculate the incoming orbit
Orbit incoming_orbit;
OrbitalManeuverCalculator.PatchedConicInterceptBody(initial_orbit, target_body, NodeList[0].dV, NodeList[0].UT, UT_arrival, out incoming_orbit);
double burnUT = incoming_orbit.NextPeriapsisTime(incoming_orbit.StartUT);
NodeList.Add(new ManeuverParameters(OrbitalManeuverCalculator.DeltaVToCircularize(incoming_orbit, burnUT), burnUT));
}
return(NodeList);
}
