Spacecraft Overview

The Spacecraft type represents a spacecraft with orbital state, time, physical properties, and trajectory history.

Spacecraft Fields

• state::OrbitState — Orbital state (position and velocity) - see State
• time::Time — Epoch - see Time
• mass::T — Total mass (kg) - see Mass
• coord_sys::CoordinateSystem — Coordinate system (origin and axes) - see Coordinate System
• history::SpacecraftHistory — Trajectory history - see History
• name::String — User label
• cad_model::CADModel — 3D model for visualization - see CAD Model

Basic Construction

using AstroModels, AstroStates, AstroEpochs

# Create spacecraft with all key properties
sc = Spacecraft(
    state = CartesianState([7000.0, 300.0, 0.0, 0.0, 7.5, 0.03]),
    time = Time("2015-09-21T12:23:12", TAI(), ISOT()),
    mass = 1000.0,
    coord_sys = CoordinateSystem(earth, ICRFAxes()),
    name = "MySat"
)

See the Spacecraft constructor documentation for default values and additional options.

Type Promotion

Spacecraft automatically promotes numeric types for automatic differentiation:

using ForwardDiff

# Mass with dual number
sc = Spacecraft(
    state = CartesianState([7000.0, 300.0, 0.0, 0.0, 7.5, 0.03]),
    time = Time("2015-09-21T12:23:12", TAI(), ISOT()),
    mass = ForwardDiff.Dual(1000.0, 1.0)
)

# All numeric fields promote to Dual
sc.state  # OrbitState with Dual elements
sc.mass   # Dual number
sc.time   # Time with Dual jd1, jd2

The numeric type T is determined by: T = promote_type(eltype(state), typeof(time.jd1), typeof(mass))

Deep Copy

sc_copy = deepcopy(sc)
# All mutable fields (state, time, history) are independently copied