spice.archived_kernels

spice.archived_kernels

SPICE kernels management for archived datasets.

To access subsets of datasets, wrap the NAIF server’s subsetds.pl script. The Perl script subsetds.pl (see BASE_URL below) requires as input: - the dataset name - start and stop of the time interval - a constant named “Subset” to identify the action for this Perl script We can assemble these parameters into a payload dictionary for the requests.get call and we manage different potential actions on the zipfile with a Subsetter class, that only requires the mission identifier, start and stop as parameters.

Classes

Name	Description
Subsetter	Class to manage retrieving subset SPICE kernel lists.

Subsetter

spice.archived_kernels.Subsetter(mission, start, stop=None, save_location=None)

[source]

Class to manage retrieving subset SPICE kernel lists.

Attributes

Name	Type	Description
kernel_names	list[str]	Names of kernels for the given time range.

Notes

The following methods are available on this class:

download_kernels() – Download SPICE kernels.
get_metakernel() – Get metakernel file from NAIF and adjust paths to match local storage.

Methods

Name	Description
download_kernels	Download SPICE kernels.
get_local_path	Return local storage path from Kernel URL.
get_metakernel	Download metakernel file from NAIF, adapt paths to match local storage

download_kernels

spice.archived_kernels.Subsetter.download_kernels(
    overwrite=False,
    non_blocking=False,
    quiet=False,
)

Download SPICE kernels.

Parameters

Name	Type	Description	Default
overwrite	bool	Overwrite existing kernels. Defaults to False.	`False`
non_blocking	bool	Use Dask client for parallel download. Defaults to False.	`False`
quiet	bool	Suppress name and path of downloaded kernels. Defaults to False.	`False`

[source]

get_local_path

spice.archived_kernels.Subsetter.get_local_path(url)

Return local storage path from Kernel URL.

Uses self.save_location if given.

Parameters

Name	Type	Description	Default
url	str	URL of the kernel file.	required

[source]

get_metakernel

spice.archived_kernels.Subsetter.get_metakernel()

Download metakernel file from NAIF, adapt paths to match local storage and return local path to metakernel file.

Uses self.save_location if given, otherwise planetarypy archive.

[source]

Functions

Name	Description
download_one_url	Download a single URL to a local path.
get_metakernel_and_files	For a given mission and start/stop times, download the kernels and get metakernel path.
list_cached_kernels	Enumerate SPICE kernel files cached locally under `KERNEL_STORAGE`.
list_kernels_for_day	List all kernels for a given time range of a mission.

download_one_url

spice.archived_kernels.download_one_url(url, local_path, overwrite=False)

Download a single URL to a local path.

Parameters

Name	Type	Description	Default
url	str	URL to download	required
local_path	Path	Path where to save the file	required
overwrite	bool	Whether to overwrite existing files, by default False	`False`

[source]

get_metakernel_and_files

spice.archived_kernels.get_metakernel_and_files(
    mission,
    start,
    stop,
    save_location=None,
    quiet=False,
)

For a given mission and start/stop times, download the kernels and get metakernel path.

Parameters

Name	Type	Description	Default
mission	str	Mission shorthand in datasets dataframe.	required
start	str	Start time in either ISO or yyyy-jjj format.	required
stop	str	Stop time in either ISO or yyyy-jjj format.	required
save_location	str	Overwrite default storing in planetarypy archive. Defaults to None.	`None`
quiet	bool	Suppress download feedback. Defaults to False.	`False`

[source]

list_cached_kernels

spice.archived_kernels.list_cached_kernels()

Enumerate SPICE kernel files cached locally under KERNEL_STORAGE.

Walks {storage_root}/spice_kernels/ and groups what it finds by top-level subdirectory:

"generic" — leapseconds, planetary constants, DE-series and satellite ephemerides under spice_kernels/generic/.
"<mission>" — per-mission archive subsets (one entry per mission shorthand seen on disk).

Returns an empty dict if no kernels have been cached yet. The Path list for each group is sorted by filename; metakernels (*.tm, *.mk) appear alongside the binary kernels.

Example::

>>> from planetarypy.spice.archived_kernels import list_cached_kernels
>>> cached = list_cached_kernels()
>>> sorted(cached.keys())
['cassini', 'generic', 'mro']
>>> [p.name for p in cached['generic']]
['de430.bsp', 'naif0012.tls', 'pck00010.tpc', ...]

[source]

list_kernels_for_day

spice.archived_kernels.list_kernels_for_day(mission, start, stop='')

List all kernels for a given time range of a mission.

Parameters

Name	Type	Description	Default
mission	str	Mission shorthand in datasets dataframe.	required
start	str	Start time in either ISO or yyyy-jjj format.	required
stop	str	Stop time in either ISO or yyyy-jjj format. Defaults to None.	`''`

[source]