0 = circular, approaching 1 = highly elongated ellipse (e.g. a comet)
Tilt of the orbital plane, degrees. >90° signals retrograde motion (e.g. Triton) — direction is derived from this, not a separate flag.
Rotation of the orbit's ellipse around the parent's polar axis, degrees
Rotation of the ellipse within its own plane, degrees
Position along the orbit at epoch, degrees (0 = periapsis)
Orbital period, days
ISO 8601 date meanAnomalyAtEpochDeg is measured from. Give a UTC Z
or an explicit offset (2000-01-01T12:00:00Z) or a bare date
(2000-01-01, which ISO defines as UTC). A date-time with no offset is
read as UTC by this engine — JavaScript's own Date would read it as
the viewer's LOCAL time, putting every body somewhere slightly
different per time zone — and is flagged by validateSystemData as an
invalid-orbit warning (epoch-without-offset), since the author
probably didn't mean either reading on purpose.
OptionalreferencePole of the plane inclinationDeg/longitudeOfAscendingNodeDeg/
argumentOfPeriapsisDeg are measured against, in the system's
reference frame (see PoleDirection). Unset means the reference plane
itself. That plane's own x-axis (where the ascending node is measured
from) is its ascending node on the reference plane — see
orientation.ts's planeBasis. Typically the parent's own pole (moon
elements quoted against the planet's equator) or a moon's local
Laplace pole; a ringed planet's moons only line up with its rings when
this matches the planet's pole.
Semi-major axis, km