Wrong error on missing reference frame for MSL Descent Stage

[jumpjack]

Why am I getting an error about missing reference frame for MSL rover upon using this function, which does not mention rover but spacecraft?

const MSLpos = TimeCraft.Spice.spkpos('-76', etEDL, 'J2000', 'LT+S', '499').ptarg;

I included kernel msl_edl_v01.bsp , de425s.bsp, msl_v08.tf and naif0012.tls; kernel msl_v08.tf contains reference frames for both Descent Stage (-76) and Rover (-76000), so why doesn't spkpos() properly refer to descent stage?

[jumpjack]

This line:
const MSLpos = TimeCraft.Spice.spkpos('MSL', etEDL, 'IAU_MARS', 'LT+S', 'MARS').ptarg;

causes error:
At epoch 3.9750156818313E+08 TDB (2012 AUG 06 05:06:08.183 TDB), there is insufficient information available to transform from reference frame -76000 (MSL_ROVER) to reference frame 1 (J2000).

in cspice.js:3

This line:
const MSLpos = TimeCraft.Spice.spkpos('MSL_SPACECRAFT', etEDL, 'IAU_MARS', 'LT+S', 'MARS').ptarg;

causes error:
Insufficient ephemeris data has been loaded to compute the position of -76010 (MSL_SPACECRAFT) relative to 0 (SOLAR SYSTEM BARYCENTER) at the ephemeris epoch 2012 AUG 06 05:06:08.183

Kernel msl_v08.tf contains these data:

  MSL                      -76
  MSL_ROVER                -76000
  MSL_SPACECRAFT           -76010

[gkjohnson]

@jumpjack
Hello! It's best to include the full set of mission kernels unless you have a good knowledge of how SPICE kernels work and the data within. Both of the function calls you've posted work in the example page without issue with the kernels that have been imported.

Other than that I would refer to the official SPICE documentation for more details on SPICE functionality.