// Perturb an orbit by a deltaV vector
public static void Perturb(this Orbit orbit, Vector3d deltaVV, double universalTime, double deltaTime)
{
// If there is a deltaV, perturb orbit
if (deltaVV.magnitude <= 0)
{
return;
}
// Transpose deltaVV Y and Z to match orbit frame
Vector3d deltaVV_orbit = deltaVV.xzy;
Vector3d position = orbit.getRelativePositionAtUT(universalTime);
Orbit orbit2 = orbit.Clone();
orbit2.UpdateFromStateVectors(position, orbit.getOrbitalVelocityAtUT(universalTime) + deltaVV_orbit, orbit.referenceBody, universalTime);
if (!double.IsNaN(orbit2.inclination) && !double.IsNaN(orbit2.eccentricity) && !double.IsNaN(orbit2.semiMajorAxis) && orbit2.timeToAp > deltaTime)
{
orbit.inclination = orbit2.inclination;
orbit.eccentricity = orbit2.eccentricity;
orbit.semiMajorAxis = orbit2.semiMajorAxis;
orbit.LAN = orbit2.LAN;
orbit.argumentOfPeriapsis = orbit2.argumentOfPeriapsis;
orbit.meanAnomalyAtEpoch = orbit2.meanAnomalyAtEpoch;
orbit.epoch = orbit2.epoch;
orbit.referenceBody = orbit2.referenceBody;
orbit.Init();
orbit.UpdateFromUT(universalTime);
}
else
{
orbit.UpdateFromStateVectors(position, orbit.getOrbitalVelocityAtUT(universalTime) + deltaVV_orbit, orbit.referenceBody, universalTime);
orbit.Init();
orbit.UpdateFromUT(universalTime);
}
}
// Constructor & calculate
public void Propagate(Navigator navigator, Orbit orbit0, double UT0, double UTf, double dT, Control control, double m0in)
{
// Control parameters
var throttle = control.throttle;
var sailon = control.sailon;
var frame = control.frame;
// Update segment initial mass
m0 = m0in;
// Working orbit at each time step
Orbit orbit = orbit0.Clone();
// Number of time steps
int nsteps = Convert.ToInt32(Math.Ceiling((UTf - UT0) / dT));
// Last time step size
double dTlast = (UTf - UT0) % dT;
// Current universal time
double UT;
// Current mass
double m0i = m0;
// Reseting time step to sample orbits for saving
double dTchoose = 0.0;
// List of orbits to preview
orbits = new List<Orbit>();
// Add initial orbit
orbits.Add(orbit0.Clone());
// Iterate for nsteps
for (int i = 0; i < nsteps; i++) {
// Last step goes to UTf
if (i == nsteps - 1) {
dT = dTlast;
UT = UTf;
} else {
UT = UT0 + i * dT;
}
// Spacecraft reference frame
Quaternion sailFrame = frame.qfn(orbit, UT, control.angles);
// Total deltaV vector
Vector3d deltaVV = new Vector3d(0.0, 0.0, 0.0);
// Accumulated mass change for all engines
double dms = 0.0;
// Iterate over engines
foreach (var pe in navigator.persistentEngines) {
// Only count thrust of engines that are not shut down in preview
if (pe.engine.getIgnitionState) {
// Thrust unit vector
Vector3d thrustUV = sailFrame * new Vector3d(0.0, 1.0, 0.0);
// Isp: Currently vacuum. TODO: calculate at current air pressure
float isp = pe.engine.atmosphereCurve.Evaluate(0);
// Thrust vector
float thrust = throttle * pe.engine.maxThrust;
// Calculate deltaV vector
double demandMass;
deltaVV += pe.CalculateDeltaVV(m0i, dT, thrust, isp, thrustUV, out demandMass);
// Update mass usage
dms += demandMass * pe.densityAverage;
}
}
// Iterate over sails
if (sailon) {
foreach (var s in navigator.solarSails) {
// Check if sail in sun
double sunlightFactor = 1.0;
if (!SolarSailPart.inSun(orbit, UT)) {
sunlightFactor = 0.0;
}
// Normal vector
Vector3d n = sailFrame * new Vector3d(0.0, 1.0, 0.0);
// Force on sail
Vector3d solarForce = SolarSailPart.CalculateSolarForce(s, orbit, n, UT) * sunlightFactor;
// Sail acceleration
Vector3d solarAccel = solarForce / m0i / 1000.0;
// Update deltaVV
deltaVV += solarAccel * dT;
}
}
// Update starting mass for next time step
m0i -= dms;
// Update
// Update orbit
orbit.Perturb(deltaVV, UT);
// Increment time step at which to sample orbits
dTchoose += dT;
// Orbit period
double TP = orbit.period;
// Decide whether to add orbit to list of orbits to draw
if (i == nsteps - 1) { // Always add last orbit
orbits.Add(orbit.Clone());
} else if (dTchoose >= TP / 360) { // If 1/360th of current period passed, add orbit
orbits.Add(orbit.Clone());
// Reset dTchoose
dTchoose = 0.0;
}
}
// Update final mass
m1 = m0i;
}
public double m1; // Final mass
// Constructor & calculate
public void Propagate(Navigator navigator, Orbit orbit0, double UT0, double UTf, double dT, Control control, double m0in)
{
// Control parameters
var throttle = control.throttle;
var sailon = control.sailon;
var frame = control.frame;
// Update segment initial mass
m0 = m0in;
// Working orbit at each time step
Orbit orbit = orbit0.Clone();
// Number of time steps
int nsteps = Convert.ToInt32(Math.Ceiling((UTf - UT0) / dT));
// Last time step size
double dTlast = (UTf - UT0) % dT;
// Current universal time
double UT;
// Current mass
double m0i = m0;
// Reseting time step to sample orbits for saving
double dTchoose = 0.0;
// List of orbits to preview
orbits = new List <Orbit>();
// Add initial orbit
orbits.Add(orbit0.Clone());
// Iterate for nsteps
for (int i = 0; i < nsteps; i++)
{
// Last step goes to UTf
if (i == nsteps - 1)
{
dT = dTlast;
UT = UTf;
}
else
{
UT = UT0 + i * dT;
}
// Spacecraft reference frame
Quaternion sailFrame = frame.qfn(orbit, UT, control.angles);
// Total deltaV vector
Vector3d deltaVV = new Vector3d(0.0, 0.0, 0.0);
// Accumulated mass change for all engines
double dms = 0.0;
// Iterate over engines
foreach (var pe in navigator.persistentEngines)
{
// Only count thrust of engines that are not shut down in preview
if (pe.engine.getIgnitionState)
{
// Thrust unit vector
Vector3d thrustUV = sailFrame * new Vector3d(0.0, 1.0, 0.0);
// Isp: Currently vacuum. TODO: calculate at current air pressure
float isp = pe.engine.atmosphereCurve.Evaluate(0);
// Thrust vector
float thrust = throttle * pe.engine.maxThrust;
// Calculate deltaV vector
double demandMass;
deltaVV += pe.CalculateDeltaVV(m0i, dT, thrust, isp, thrustUV, out demandMass);
// Update mass usage
dms += demandMass * pe.densityAverage;
}
}
// Iterate over sails
if (sailon)
{
foreach (var s in navigator.solarSails)
{
// Check if sail in sun
double sunlightFactor = 1.0;
if (!SolarSailPart.inSun(orbit, UT))
{
sunlightFactor = 0.0;
}
// Normal vector
Vector3d n = sailFrame * new Vector3d(0.0, 1.0, 0.0);
// Force on sail
Vector3d solarForce = SolarSailPart.CalculateSolarForce(s, orbit, n, UT) * sunlightFactor;
// Sail acceleration
Vector3d solarAccel = solarForce / m0i / 1000.0;
// Update deltaVV
deltaVV += solarAccel * dT;
}
}
// Update starting mass for next time step
m0i -= dms;
// Update
// Update orbit
orbit.Perturb(deltaVV, UT);
// Increment time step at which to sample orbits
dTchoose += dT;
// Orbit period
double TP = orbit.period;
// Decide whether to add orbit to list of orbits to draw
if (i == nsteps - 1) // Always add last orbit
{
orbits.Add(orbit.Clone());
}
else if (dTchoose >= TP / 360) // If 1/360th of current period passed, add orbit
{
orbits.Add(orbit.Clone());
// Reset dTchoose
dTchoose = 0.0;
}
}
// Update final mass
m1 = m0i;
}
public void SetOrbit(Orbit orbit)
{
m_orbit.Clone(orbit);
}