public T DeserializeFile<T>(string filename, params JsonConverter[] converters)
{
    TextAsset text = Resources.Load<TextAsset>(filename);
    T data = JsonConvert.DeserializeObject<T>(text.ToString(), converters);
    return data;
}

public Galaxy LoadSol(ref Galaxy galaxy, string path = "Data/SolarSystem.json")
{
    JsonSerializerSettings settings = new();
    Galaxy additionalData = DeserializeFile<Galaxy>(path,
        new CoreObjectConverter<Galaxy>(new GalaxyConverter()),
        new CoreObjectConverter<StarSystem>(new StarSystemConverter()),
        new CoreObjectConverter<Star>(new StarConverter()),
        new CoreObjectConverter<Planet>(new PlanetConverter()));
    foreach ((string key, StarSystem system) in additionalData.Systems)
    {
        galaxy[key] = system;
    }
}

Galaxy galaxy = new Galaxy("Milky Way");
LoadSol(ref galaxy);

Galaxy     galaxy = new Galaxy("Milky Way");
StarSystem sol    = new StarSystem("Sol");

// Star.Sol and Planet.Earth are included as examples with hardcoded values at J2000.
// You should create stars and planets with the appropriate constructors or factory methods
Star   sun   = Star.Sun;
Planet earth = Planet.Earth;

galaxy.AddSystem(sol);
sun.AddPlanet(earth);
sol.AddStar(sun);

// iterate on every body in the Solar system or use the provided Hiearrchy enumerator,
// or use CelestialBody.PreOrderVisit | LevelOrderVisit
planet.OrbitState.Propagate(DateTime.Today);

float delta = speed * 86400 * Time.deltaTime;
planet.OrbitState.Propagate(delta);

// When you need to use the calculated position, in the gameobject representing your Planet:
transform.position = planet.OrbitState.Position.FromMetrestoAU(unitsPerAU).ToXZY();

Star primary = stars[0];
Star companion = stars[1];

OrbitalData o = companion.OrbitalData;
Barycentre barycentre = new(primary.StarSystem);
(Length a1, Length a2) = barycentre.CalculateSemiMajorAxes(primary, companion, o.SemiMajorAxis);

primary.Attractor   = barycentre;
companion.Attractor = barycentre;

// Only a, e, i, Ω (longitude of ascending node), ω (argument of periastron, and P are necessary
// i here is zero to make sure that your view is aligned to the orbital plane,
// but in catalogues this value represents the inclination as seen from Earth
OrbitalData o1 = new(a1, o.Eccentricity, Angle.Zero, o.LongitudeAscendingNode, o.ArgumentPeriapsis, o.Period,
                     Duration.Zero, Angle.Zero,
                     trueAnomaly: Angle.FromDegrees(0));
// ω is shifted 180° to place the other state at the opposite side
// however you could calculate the "current position" from the time of periastron T0 if you have it
OrbitalData o2 = new(a2, o.Eccentricity, Angle.Zero,
                     o.LongitudeAscendingNode, //Angle.FromDegrees((o.LongitudeAscendingNode.Value + 180) % 360),
                     Angle.FromDegrees((o.ArgumentPeriapsis.Value + 180) % 360), o.Period,
                     Duration.Zero, Angle.Zero,
                     trueAnomaly: Angle.FromDegrees(0));

primary.OrbitalData   = o1;
companion.OrbitalData = o2;

IPropagator propagator = new Kinematic();
primary.OrbitState.SetPropagator(propagator);
companion.OrbitState.SetPropagator(propagator);

CelestialBody earth = Common.Earth;
CelestialBody mars  = Common.Mars;

DateTime epochDeparture = new DateTime(2018, 12, 1, 0, 0, 0, DateTimeKind.Utc);
DateTime epochArrival   = epochDeparture.AddYears(2);

earth.OrbitState.SetAttractor(Common.Sun);
mars.OrbitState.SetAttractor(Common.Sun);
earth.OrbitState.Propagate(epochDeparture);
mars.OrbitState.Propagate(epochArrival);

IzzoLambertSolver solver = new IzzoLambertSolver();
Manoeuvre m = Manoeuvre.Lambert(earth.OrbitState, mars.OrbitState, solver);

Planet earth = Common.Earth;
Planet mars  = Common.Mars;

earth.OrbitState.SetAttractor(Common.Sun);
mars.OrbitState.SetAttractor(Common.Sun);

TransferPlanner tp        = new CelestialMechanics.Manoeuvres.TransferPlanner(earth, mars);
DateTime        startDate = new DateTime(2025, 1, 1, 0, 0, 0, DateTimeKind.Utc);
tp.CalculateTransferWindows(startDate, 200, 50);
TransferData transfer = tp.OrderByDeltaV().First();
// you can also order the transfers in order of transfer duration
// via tp.OrderByTransferTime()

// Values from Project Longshot to Alpha Centauri Orbit
Length       distanceAlphaCentauri = Length.FromLightYears(4.344);
Speed        maxSpeed              = Relativity.SpeedFromFractionOfC(0.048f); // page 20, 59
Acceleration acceleration          = Acceleration.FromMetersPerSecondSquared(0.429); // page 68

RelativisticTravelData result = Relativity.CalculateTravel(distanceAlphaCentauri, maxSpeed, acceleration);