LayupObservatory loads de440s.bsp, the short variant of DE440, which covers only 1849 Dec 25 to 2150 Jan 21. Any observation earlier than that fails when the observer position is computed:
SPICE(SPKINSUFFDATA) -- Insufficient ephemeris data has been loaded to compute the state
of 399 (EARTH) relative to 0 (SOLAR SYSTEM BARYCENTER) at the ephemeris epoch
1845 DEC 15 00:42:02.591.
Hit on (5) Astraea, discovered 1845 — its earliest observations fall ten days short of four years before the kernel begins.
The mismatch is the awkward part: ASSIST integrates against linux_p1550p2650.440, which spans 1550–2650, so the dynamics reach three centuries further back than the observer positions that feed them. A user fitting a 19th-century arc gets a raw SPICE exception rather than anything naming the cause.
Two things would help: an error that names the kernel and its span, and an option to load the full de440.bsp (1550–2650) for historical arcs. Presumably de440s was chosen for download size — roughly 32 MB against 114 MB — which is a reasonable default, just not a silent one.
LayupObservatoryloadsde440s.bsp, the short variant of DE440, which covers only 1849 Dec 25 to 2150 Jan 21. Any observation earlier than that fails when the observer position is computed:Hit on (5) Astraea, discovered 1845 — its earliest observations fall ten days short of four years before the kernel begins.
The mismatch is the awkward part: ASSIST integrates against
linux_p1550p2650.440, which spans 1550–2650, so the dynamics reach three centuries further back than the observer positions that feed them. A user fitting a 19th-century arc gets a raw SPICE exception rather than anything naming the cause.Two things would help: an error that names the kernel and its span, and an option to load the full
de440.bsp(1550–2650) for historical arcs. Presumablyde440swas chosen for download size — roughly 32 MB against 114 MB — which is a reasonable default, just not a silent one.