SPICE stew: Spice Pointing Inference and Correction Exploiting the Spice Toolkit to Eliminate Wobbles

Tools to correct the pointing of SolarOrbiter/SPICE using data from the SPICE toolkit.

Installation

Prerequisite: Solar Orbiter SPICE Kernels

The SPICE kernels for Solar Orbiter are required in order to compute the pointing of SPICE.

The easiest way to install them and keep them up to date is to clone ESA's git repository (~1 GiB) to a location of your choice:

git clone https://repos.cosmos.esa.int/socci/scm/spice_kernels/solar-orbiter.git /path/to/spice_kernels/SOLAR-ORBITER/

and replace PATH_VALUES = = ( '..' ) in all mk/*.tm files with PATH_VALUES = ( '/path/to/spice_kernels/SOLAR-ORBITER/kernels' ) (see full instruction in the repository's README).

Then, set the $SPICE_KERNELS_SOLO environment variable to point to this path. This can be done by adding the following line to your ~/.bashrc:

export SPICE_KERNELS_SOLO=/path/to/spice_kernels/SOLAR-ORBITER/kernels

SPICE stew

To install the SPICE stew package, run:

pip install spice_stew

Usage

From the command line

Use the spice_stew command in the terminal, eg:

spice_stew /archive/SOLAR-ORBITER/SPICE/fits/level2/2021/09/14/solo_L2_spice-n-ras_20210914T025031_V06_67109159-000.fits -O ~/spice_stew_test/ --plot-results

Run spice_stew -h for more options.

In Python

Use the spice_stew.correct_spice_pointing function, eg:

import spice_stew
ssp = spice_stew.SpiceSpicePointing()
spice_stew.correct_spice_pointing(
    ssp,
    '/archive/SOLAR-ORBITER/SPICE/fits/level2/2021/09/14/solo_L2_spice-n-ras_20210914T025031_V03_67109159-000.fits',
    '~/spice_stew_test/',
    plot_results=True,
    )

Troubleshooting

• SPICE(NOSUCHFILE)The first file '../ck/[...].bc' specified by KERNELS_TO_LOAD in the file [...]/mk/[...]..tm could not be located. is raised when the PATH_VALUES have not been updated in the meta-kernels during the [installation of the kernels][prerequisite-solar-orbiter-spice-kernels].

• SpiceNOFRAMECONNECT: At epoch ..., there is insufficient information available to transform from reference frame -144991 (SOLO_SUN_RTN) to reference frame -144000 (SOLO_SRF). is raised when the requested date is not in the as-flown SPICE kernels. This happens either because the kernels have not been updated, or because a date in the future is being requested. In the 1st case, you can update the kernels with git pull.

Reference / License

This package is released under a MIT open source licence. See LICENSE.txt.