// Create an NBody and check it's mass
public void EccentricityPrediction()
{
const float mass = 1000f;
GameObject star = TestSetupUtils.CreateNBody(mass, new Vector3(0, 0, 0));
NBody starNbody = star.GetComponent <NBody>();
const float orbitRadius = 10f;
GameObject planet = TestSetupUtils.CreatePlanetInOrbitUniversal(starNbody, 1f, orbitRadius);
OrbitUniversal orbitU = planet.GetComponent <OrbitUniversal>();
OrbitPredictor op = TestSetupUtils.AddOrbitPredictor(planet, star);
Assert.NotNull(op);
double[] ecc_values = { 0, 0.1, 0.7, 0.9, 0.99, 1.01, 1.5, 2 };
foreach (double ecc in ecc_values)
{
Debug.LogFormat("#### EccentricityPrediction ecc={0}", ecc);
orbitU.eccentricity = ecc;
TestSetupUtils.SetupGravityEngine(star, planet);
op.TestRunnerSetup();
OrbitUniversal predictedOrbit = op.GetOrbitUniversal();
Assert.NotNull(predictedOrbit);
CompareOrbits(orbitU, predictedOrbit, small);
}
}
// Create an NBody and check it's mass
public void CirclePrediction()
{
const float mass = 1000f;
GameObject star = TestSetupUtils.CreateNBody(mass, new Vector3(0, 0, 0));
NBody starNbody = star.GetComponent <NBody>();
const float orbitRadius = 10f;
GameObject planet = TestSetupUtils.CreatePlanetInOrbitUniversal(starNbody, 1f, orbitRadius);
OrbitUniversal orbitU = planet.GetComponent <OrbitUniversal>();
OrbitPredictor op = TestSetupUtils.AddOrbitPredictor(planet, star);
Assert.NotNull(op);
double[] p_values = { 10, 100, 1000 };
foreach (double p in p_values)
{
Debug.LogFormat("#### CirclePrediction p={0}", p);
orbitU.p = p;
TestSetupUtils.SetupGravityEngine(star, planet);
op.TestRunnerSetup();
OrbitUniversal predictedOrbit = op.GetOrbitUniversal();
Assert.NotNull(predictedOrbit);
CompareOrbits(orbitU, predictedOrbit, small);
}
}
// Create an NBody and check it's mass
public void OmegaUEllipsePrediction()
{
const float mass = 1000f;
GameObject star = TestSetupUtils.CreateNBody(mass, new Vector3(0, 0, 0));
NBody starNbody = star.GetComponent <NBody>();
const float orbitRadius = 10f;
GameObject planet = TestSetupUtils.CreatePlanetInOrbitUniversal(starNbody, 1f, orbitRadius);
OrbitUniversal orbitU = planet.GetComponent <OrbitUniversal>();
// Need a bit of incl, otherwise omegaU comes back as omegaL.
orbitU.inclination = 10;
orbitU.eccentricity = 0.05;
OrbitPredictor op = TestSetupUtils.AddOrbitPredictor(planet, star);
Assert.NotNull(op);
double[] ou_values = { 0, 1, 5, 10, 30, 60, 90, 180, 270, 355, 360 };
foreach (double ou in ou_values)
{
Debug.LogFormat("#### OmegaUPrediction ou={0}", ou);
orbitU.omega_uc = ou;
TestSetupUtils.SetupGravityEngine(star, planet);
op.TestRunnerSetup();
OrbitUniversal predictedOrbit = op.GetOrbitUniversal();
Assert.NotNull(predictedOrbit);
CompareOrbits(orbitU, predictedOrbit, small);
}
}
// Create an NBody and check it's mass
public void InclinationPrediction()
{
const float mass = 1000f;
GameObject star = TestSetupUtils.CreateNBody(mass, new Vector3(0, 0, 0));
NBody starNbody = star.GetComponent <NBody>();
const float orbitRadius = 10f;
GameObject planet = TestSetupUtils.CreatePlanetInOrbitUniversal(starNbody, 1f, orbitRadius);
OrbitUniversal orbitU = planet.GetComponent <OrbitUniversal>();
OrbitPredictor op = TestSetupUtils.AddOrbitPredictor(planet, star);
Assert.NotNull(op);
double[] incl_values = { 0, 1, 5, 10, 30, 45, 60, 90, 145, 179, 180 };
foreach (double incl in incl_values)
{
Debug.LogFormat("#### InclinationPrediction incl={0}", incl);
orbitU.inclination = incl;
TestSetupUtils.SetupGravityEngine(star, planet);
op.TestRunnerSetup();
OrbitUniversal predictedOrbit = op.GetOrbitUniversal();
Assert.NotNull(predictedOrbit);
CompareOrbits(orbitU, predictedOrbit, small);
}
}
void Update()
{
OrbitUniversal orbitU = orbitPredictor.GetOrbitUniversal();
float apogee = (float)orbitU.GetApogee();
apogee_text.text = string.Format(apogee_str, apogee);
if (orbitU.eccentricity < 1f)
{
float perigee = (float)orbitU.GetPerigee();
perigee_text.text = string.Format(perigee_str, perigee);
}
else
{
perigee_text.text = string.Format(" Perigee: N/A");
}
e_text.text = string.Format(ecc_str, orbitU.eccentricity);
i_text.text = string.Format(incl_str, orbitU.inclination);
UOmega_text.text = string.Format(Omega_str, orbitU.omega_uc);
LOmega_text.text = string.Format(omega_str, orbitU.omega_lc);
}
/// <summary>
/// Computes the transfer and updates all the ghost bodies.
/// </summary>
/// <returns></returns>
private void ComputeTransfer()
{
double timeNow = ge.GetPhysicalTimeDouble();
// First using the transfer time, move the ghost Moon to position at SOI arrival.
// Call evolve via LockAtTime on the ghostMoon to move it. Set position based on this.
double t_flight = tflightFactor * timeHohmann;
double timeatSoi = timeNow + t_flight;
ghostMoonOrbit[MOON_SOI_ENTER].LockAtTime(timeatSoi);
// Determine the moon phase angle
double moonPhase = ghostMoonSoiEnterOrbitPredictor.GetOrbitUniversal().phase;
// Place the TLI ship at the user-requested angle wrt planet-moon line
// Put ghost ship in same orbit geometry as the moon, assuming it is circular. Then
// can use same phase value.
// (Ship needs to reach this departure point, it may not even be on the ship orbit
// in general).
ghostShipOrbit[TLI].phase = shipTLIAngleDeg + (moonPhase + 180f);
ghostShipOrbit[TLI].inclination = ghostMoonOrbit[MOON_SOI_ENTER].inclination;
ghostShipOrbit[TLI].omega_lc = ghostMoonOrbit[MOON_SOI_ENTER].omega_lc;
ghostShipOrbit[TLI].omega_uc = ghostMoonOrbit[MOON_SOI_ENTER].omega_uc;
ghostShipOrbit[TLI].p_inspector = shipOrbit.p;
ghostShipOrbit[TLI].Init();
ghostShipOrbit[TLI].LockAtTime(0);
// Place the SOI enter ship at the user-requested angle in an SOI orbit. Lock at time 0 so the phase
// is held per the user input.
ghostShipOrbit[ENTER_SOI].phase = soiAngleDeg + moonPhase;
ghostShipOrbit[ENTER_SOI].inclination = soiInclination + shipOrbit.inclination;
ghostShipOrbit[ENTER_SOI].omega_lc = ghostMoonOrbit[MOON_SOI_ENTER].omega_lc;
ghostShipOrbit[ENTER_SOI].omega_uc = ghostMoonOrbit[MOON_SOI_ENTER].omega_uc;
ghostShipOrbit[ENTER_SOI].Init();
ghostShipOrbit[ENTER_SOI].LockAtTime(0);
// Find the line to the ENTER_SOI position. Ship departs from that line continued through planet
// at the shipRadius distance (assumes circular ship orbit)
// TODO: Handle planet not at (0,0,0)
Vector3d soiEntryPos = ge.GetPositionDoubleV3(ghostShip[ENTER_SOI]);
Vector3d planetPos = ge.GetPositionDoubleV3(planet);
Vector3d departurePoint = ge.GetPositionDoubleV3(ghostShip[TLI]);
// Use Lambert to find the departure velocity to get from departure to soiEntry
// Since we need 180 degrees from departure to arrival, use LambertBattin
lambertB = new LambertBattin(ghostShip[TO_MOON], planet, departurePoint, soiEntryPos, shipOrbit.GetAxis());
// apply any time of flight change
bool reverse = !shortPath;
const bool df = false;
const int nrev = 0;
int error = lambertB.ComputeXfer(reverse, df, nrev, t_flight);
if (error != 0)
{
Debug.LogWarning("Lambert failed to find solution. error=" + error);
return;
}
// Check Lambert is going in the correct direction
//Vector3 shipOrbitAxis = Vector3.Cross(ge.GetPhysicsPosition(spaceship), ge.GetVelocity(spaceship) ).normalized;
//Vector3 tliOrbitAxis = Vector3.Cross(departurePoint.ToVector3(), lambertB.GetTransferVelocity().ToVector3()).normalized;
Vector3 shipOrbitAxis = Vector3.Cross(ge.GetVelocity(spaceship), ge.GetPhysicsPosition(spaceship)).normalized;
Vector3 tliOrbitAxis = Vector3.Cross(lambertB.GetTransferVelocity().ToVector3(), departurePoint.ToVector3()).normalized;
if (Vector3.Dot(shipOrbitAxis, tliOrbitAxis) < 0)
{
error = lambertB.ComputeXfer(!reverse, df, nrev, t_flight);
if (error != 0)
{
Debug.LogWarning("Lambert failed to find solution for reverse path. error=" + error);
return;
}
}
Debug.LogFormat("tli_vel={0}", lambertB.GetTransferVelocity());
ghostShipOrbit[TO_MOON].InitFromRVT(departurePoint, lambertB.GetTransferVelocity(), timeNow, planet, false);
// Set velocity for orbit around moon. Will be updated every frame
ghostShipOrbit[SOI_HYPER].InitFromRVT(soiEntryPos, lambertB.GetFinalVelocity(), timeNow, ghostMoon[MOON_SOI_ENTER], false);
// Find the exit point of the hyperbola in the SOI
OrbitUtils.OrbitElements oe = OrbitUtils.RVtoCOE(soiEntryPos, lambertB.GetFinalVelocity(), ghostMoon[MOON_SOI_ENTER], false);
Vector3d soiExitR = new Vector3d();
Vector3d soiExitV = new Vector3d();
OrbitUtils.COEtoRVMirror(oe, ghostMoon[MOON_SOI_ENTER], ref soiExitR, ref soiExitV, false);
// Find time to go around the moon. TOF requires relative positions!!
Vector3d ghostSoiEnterPos = ge.GetPositionDoubleV3(ghostMoon[MOON_SOI_ENTER]);
Vector3d soiEnterRelative = soiEntryPos - ghostSoiEnterPos;
Vector3d soiExitRelative = soiExitR - ghostSoiEnterPos;
Vector3d soiExitVelRelative = soiExitV - ge.GetVelocityDoubleV3(ghostMoon[MOON_SOI_ENTER]);
double hyperTOF = ghostShipOrbit[SOI_HYPER].TimeOfFlight(soiEnterRelative, soiExitRelative);
// Position the ghost moon for SOI exit (timeAtSoi includes timeNow)
t_soiExit = timeatSoi + hyperTOF;
ghostMoonOrbit[MOON_SOI_EXIT].LockAtTime(t_soiExit);
// Set position and vel for exit ship, so exit orbit predictor can run.
Vector3d ghostMoonSoiExitPos = ge.GetPositionDoubleV3(ghostMoon[MOON_SOI_EXIT]);
Vector3d ghostMoonSoiExitVel = ge.GetVelocityDoubleV3(ghostMoon[MOON_SOI_EXIT]);
ghostShipOrbit[EXIT_SOI].InitFromRVT(soiExitRelative + ghostMoonSoiExitPos,
soiExitVelRelative + ghostMoonSoiExitVel,
timeNow, planet, false);
}
