/// <summary>
/// The spaceship has a fixed orbit that is on rails (must be an OrbitUniversal).
///
/// To allow for setting of specific times and forward/backward motion implement the transfer as a
/// KeplerSequence of three OrbitUniversals:
/// - initial orbit when t less then now
/// - transfer ellipse when t between now and (now + transfer_time)
/// - destination orbit when t greater than (now + transfer_time)
///
/// </summary>
private void TransferOnRails()
{
// initial orbit - needs to be OrbitUniversal (could morph an OrbitEllipse, but keep things simple)
OrbitUniversal initialOrbit = spaceshipNBody.GetComponent <OrbitUniversal>();
if (initialOrbit == null)
{
Debug.LogError("script assumes ship orbit will be OrbitUniversal");
return;
}
KeplerSequence keplerSeq = spaceshipNBody.GetComponent <KeplerSequence>();
if (keplerSeq == null)
{
Debug.LogError("Cannot do on-rails transfer. Ship does not have a KeplerSequence");
return;
}
// Kepler sequence already has the initial orbit.
// transfer orbit
Vector3d xfer_r0 = lambertU.GetTransferPositionDouble();
Vector3d xfer_v0 = lambertU.GetTransferVelocityDouble();
double xfer_t = ge.GetPhysicalTimeDouble();
keplerSeq.AppendElementRVT(xfer_r0, xfer_v0, xfer_t, false, spaceshipNBody, starNBody, null);
// destination orbit
double dest_t = xfer_t + transferTime;
Vector3d dest_v = new Vector3d(targetData.GetPhysicsVelocityForEllipse(targetData.phase));
Vector3d dest_r = new Vector3d(targetData.GetPhysicsPositionforEllipse(targetData.phase));
keplerSeq.AppendElementRVT(dest_r, dest_v, dest_t, false, spaceshipNBody, starNBody, SequenceDoneCallback);
}
/// <summary>
/// Set up a KeplerSeqeunce to do the three phases of the transfer as Kepler mode conics.
///
/// Add all the ghost orbits with the required times
/// </summary>
/// <param name="transferTime"></param>
private void TransferOnRails()
{
// the ship needs to have a KeplerSequence
KeplerSequence kseq = spaceship.GetComponent <KeplerSequence>();
if (kseq == null)
{
Debug.LogError("Could not find a KeplerSequence on " + spaceship.name);
return;
}
// Ellipse 1: shipPos/shipvel already phased by the caller.
double t_start = ge.GetPhysicalTime();
double t_toSoi = timeHohmann * tflightFactor;
KeplerSequence.ElementStarted noCallback = null;
Vector3d r0 = new Vector3d();
Vector3d v0 = new Vector3d();
double time0 = 0;
ghostShipOrbit[TO_MOON].GetRVT(ref r0, ref v0, ref time0);
kseq.AppendElementRVT(r0, v0, t_start, true, spaceship, planet, noCallback);
// Hyperbola: start at t + transferTime
// Need to add wrt to ghostMoon (relative=true), then for actual Kepler motion want it around moon
ghostShipOrbit[SOI_HYPER].GetRVT(ref r0, ref v0, ref time0);
OrbitUniversal hyperObit = kseq.AppendElementRVT(r0, v0, t_start + t_toSoi, true, spaceship, ghostMoon[MOON_SOI_ENTER], EnterMoonSoi);
hyperObit.centerNbody = moonBody;
// Ellipse 2:
ghostShipOrbit[EXIT_SOI].GetRVT(ref r0, ref v0, ref time0);
kseq.AppendElementRVT(r0, v0, t_soiExit, true, spaceship, planet, ExitMoonSoi);
}
/// <summary>
/// Set up a KeplerSeqeunce to do the three phases of the transfer as Kepler mode conics.
///
/// Leave the existing ship orbit as the first
/// </summary>
/// <param name="transferTime"></param>
private void TransferOnRails(double transferTime, Vector3 shipPos, Vector3 shipVel, float moonOmega)
{
// the ship needs to have a KeplerSequence
KeplerSequence kseq = spaceship.GetComponent <KeplerSequence>();
if (kseq == null)
{
Debug.LogError("Could not find a KeplerSequence on " + spaceship.name);
return;
}
float moonPhaseDeg = moonOmega * (float)transferTime * Mathf.Rad2Deg;
Quaternion moonPhaseRot = Quaternion.AngleAxis(moonPhaseDeg, Vector3.forward);
// Ellipse 1: shipPos/shipvel already phased by the caller.
double t = ge.GetPhysicalTime();
KeplerSequence.ElementStarted noCallback = null;
kseq.AppendElementRVT(new Vector3d(shipPos), new Vector3d(shipVel), t, false, spaceship, planet, noCallback);
// Hyperbola: start at t + transferTime
// have targetPoint and final velocity from LambertTransfer. Need to make these wrt moon at this time
// targetPoint is w.r.t current moon position, but need to rotate around SOI by amount moon will shift
// as ship transits to moon
Vector3 targetPos = targetPoint.ToVector3();
Vector3 moonPosAtSoi = moonPhaseRot * ge.GetPhysicsPosition(moonBody);
Vector3 moonVelAtSoi = moonPhaseRot * ge.GetVelocity(moonBody);
// get the relative positions (i.e. as if moon at the origin with v=0)
Vector3 adjustedTarget = moonPhaseRot * targetPos - moonPosAtSoi;
Vector3 adjustedVel = moonPhaseRot * lambertU.GetFinalVelocity() - moonVelAtSoi;
// Create moon hyperbola at the moon position after flight to moon. This means the init cannot make reference
// to the CURRENT moon position.
Vector3d soiEnterR = new Vector3d(adjustedTarget);
Vector3d soiEnterV = new Vector3d(adjustedVel);
OrbitUniversal hyperOrbit = kseq.AppendElementRVT(soiEnterR,
soiEnterV,
t + transferTime,
true,
spaceship,
moonBody,
EnterMoonSoi);
// Find the hyperbola exit SOI position/vel
OrbitUtils.OrbitElements oe = OrbitUtils.RVtoCOE(soiEnterR, soiEnterV, moonBody, true);
Vector3d soiExitR = new Vector3d();
Vector3d soiExitV = new Vector3d();
Debug.Log("oe=" + oe);
// Gives position and velocity in relative position
OrbitUtils.COEtoRVMirror(oe, moonBody, ref soiExitR, ref soiExitV, true);
// Determine hyperbola transit time to the soiExit position
double hyperTOF = hyperOrbit.TimeOfFlight(soiEnterR, soiExitR);
//Debug.LogFormat("Hyper TOF={0} r0={1} r1={2} p={3}", hyperTOF, adjustedTarget, soiExitR,
// hyperOrbit.p);
// Ellipse 2:
// Adjust phase to allow for moon travel during hyperbola transit
// Need to set position and vel relative to the planet using position relative to moon at 0
moonPhaseDeg = moonOmega * (float)hyperTOF * Mathf.Rad2Deg;
Quaternion moonHyperRot = Quaternion.AngleAxis(moonPhaseDeg, Vector3.forward);
Vector3 moonAtExit = moonHyperRot * moonPosAtSoi;
Vector3 moonVelAtExit = moonHyperRot * moonVelAtSoi;
Vector3 soiExitwrtPlanet = soiExitR.ToVector3() + moonAtExit;
// soiexitV is relative to moon at (0,0,0) BUT frame of hyperbola does not rotate
Vector3 soiExitVelwrtPlanet = moonHyperRot * soiExitV.ToVector3() + moonVelAtExit;
Debug.LogFormat("Ellipse2: soiExitV={0} moonV={1} net={2}", soiExitV, moonVelAtExit, soiExitVelwrtPlanet);
kseq.AppendElementRVT(new Vector3d(soiExitwrtPlanet),
new Vector3d(soiExitVelwrtPlanet),
t + transferTime + hyperTOF,
true,
spaceship,
planet,
ExitMoonSoi);
running = true;
}