constants.nssdc

constants.nssdc

NSSDC Planetary Fact Sheet values, time-indexed.

NSSDC = NASA’s National Space Science Data Center at Goddard Space Flight Center, maintainer of the canonical per-body planetary fact sheets (D. R. Williams, since 1996). See https://nssdc.gsfc.nasa.gov/planetary/factsheet/ for the upstream pages.

Optional, opt-in namespace for users who want NSSDC-only data deliberately. The default top-level :mod:planetarypy.constants namespace already merges NSSDC fields transparently into each Body (filling in fields PCK doesn’t provide); reach for planetarypy.constants.nssdc only when you want:

• the NSSDC value for a field PCK also has (e.g. nssdc.Mars.GM vs the PCK value at top-level Mars.GM);
• date-indexed lookup against NSSDC’s own publication history;
• the full per-field timeline for archival / drift-tracking work.

Example::

from planetarypy.constants import Mars                  # default merged
Mars.bond_albedo                                         # NSSDC latest
Mars.GM                                                  # PCK / IAU 2015

from planetarypy.constants.nssdc import Mars             # NSSDC-only view
Mars.GM                                                  # NSSDC GM, latest

from planetarypy.constants import nssdc
nssdc.at_time("mars", "bond_albedo", "2001")             # 0.16 (1996-era)
nssdc.history("mars", "bond_albedo")                     # full timeline

The parsed archive is loaded lazily on first import; if not present in the user’s local cache, it auto-downloads from Zenodo (record id pinned in _loader.ZENODO_RECORD_ID).

Functions

Name	Description
at_time	Return the NSSDC value of body.field current as of date.
history	Full NSSDC time series for (body, field).
known_bodies	Bodies present in the NSSDC archive.

at_time

constants.nssdc.at_time(body, field, date)

Return the NSSDC value of body.field current as of date.

date may be a year ("2001"), a year-month ("2001-06"), or an ISO date ("2001-06-15"). Year/year-month resolve to the end of that period (e.g. "2001" → "2001-12-31"), so a ‘show me what was current in 2001’ query picks the latest 2001 capture.

[source]

history

constants.nssdc.history(body, field)

Full NSSDC time series for (body, field).

Returns a list of (date, Constant, wayback_url) tuples sorted oldest-first. Useful for drift-tracking studies.

[source]

known_bodies

constants.nssdc.known_bodies()

Bodies present in the NSSDC archive.

[source]