I really think this could be the greatest new feature for Celestia:
- load REAL spacecraft ephemerides (international, not just NASA)
- use the latest, official planet and moon ephemerides
- use the latest astrodynamical constants
- use official IAU coordinate systems
All this and more
is available if you use the JPL/NASA SPICE library!!ftp://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/ascii/individual_docs/intrdctn.req
If you have any concerns or questions about SPICE please send them to Chuck.Acton@jpl.nasa.gov, http://naif.jpl.nasa.gov/naif/contactinfo.html
I see two immediate advantages for Celestia to use SPICE:
- existing users get the "cool" factor of using *real* NASA/ESA science data (http://www.esa.int/, http://www.jpl.nasa.gov/)
- The Celestia user base will grow to include aerospace engineers and planetary scientists
see
- SPICE Overview http://newfrontiers.larc.nasa.gov/PDF_FILES/SPICE_Overview.pdf
- SPICE Concept http://naif.jpl.nasa.gov/naif/spiceconcept.html
- NAIF Data http://naif.jpl.nasa.gov/naif/data.html
- "SPICE toolkit" software http://naif.jpl.nasa.gov/naif/toolkit.html
- http://permanent.access.gpo.gov/lps2427/Native%20Issues/Issue62Native/article_spice.html
- http://newfrontiers.larc.nasa.gov/PDF_FILES/SPICE_for_New_Frontiers_AO.pdf
- Tutorial: ftp://naif.jpl.nasa.gov/pub/naif/misc/estec/SPICE_Tutorials_Office/
- Tutorial: http://www.rssd.esa.int/index.php?project=PSA&page=spice
- Tutorials: http://naif.jpl.nasa.gov/naif/tutorials.html
From the "NAIF Data" page you can download high precision
ephemerides from real NASA missions.
The SPICE toolkit will give you the ability to read these files
and compute all sorts of information.
The SPICE toolkit is used by scientists and engineers to produce
software for current space missions.
The documentation alone is extensive http://naif.jpl.nasa.gov/naif/doc_C.html
quote:
"The Navigation and Ancillary Information Facility (NAIF), acting under
the directions of NASA's Science Directorate, has built an information
system named "SPICE" to assist scientists in planning and interpreting
scientific observations from space-borne instruments, and to assist
engineers involved in modeling, planning and executing activities
needed to conduct space exploration missions. The use of SPICE
extends through the post-mission data analysis phase, including help
with correlation of individual instrument data sets with those from
other instruments on the same or on other spacecraft."
quote:
"SPICE data that have been peer reviewed and archived within the
Planetary Data System, or where archival is in progress but the data are
felt to be of sufficient completeness, quality and organization so as to
be useful as if formally archived, are available through the central
catalog of the PDS."
quote:
"SPICE data for currently active missions where NAIF produces the data
or otherwise has access to it, and for past missions for which SPICE
data are available, may be obtained directly from the NAIF server using
the selections below."
other data:
- Current leapseconds kernel (LSK)
- Ephemerides for planets, satellites, and some comets and asteroids (SPK)
- Planetary constants kernels (PCK)
- Topocentric locations (SPK) and reference frame definitions (FK) for earth stations
- Star catalogs (currently only the PPM catalog, in SPICE Type 1 format"
quote:
"The SPICE Toolkit is comprised of several items: 1) a large collection
of user-level application program interfaces (APIs) and underlying
subroutines and functions, provided as source code with extensive
user-focused documentation (code headers); 2) a ready-to-use library
made from the APIs, subroutines and functions described in 1); 3) a
small set of ready-built utility (application) programs expected to be of
use to many SPICE users, along with their associated User Guides; 4) a
set of technical reference documents--one for each major SPICE
functional area; and 5) a few additional documents that: describe the
contents and structure of a Toolkit package, highlight and provide
small usage examples of the most popular APIs, and provide a
permuted index based on the abstracts for all modules."
The SPICE toolkit is primarily developed in FORTRAN but is ported to C.
You can get it, here http://naif.jpl.nasa.gov/naif/toolkit.html
Please be sure to read
http://naif.jpl.nasa.gov/naif/rules.html
This is a pretty generic submission, meant to initiate the idea.
If the developers go for this, I propose adding several individual bugs for particular SPICE features. It might go something like this
- use SPICE ephemeris files (planets, moons, spacecraft,etc)
- use SPICE topocentric locations (identify surface features)
- use SPICE star catalogs (display star positions accurately)
- use SPICE planetary constants kernels (up-to-date mass, pole vector)
- use SPICE leapseconds kernels (conversion to UTC)
- use SPICE reference frame kernels
- use SPICE C-kernels (spacecraft orientation)
- use SPICE I-kernels (spacecraft instruments)
- use SPICE E-kernels (spacecraft events)
it's worth noting that all SPICE files are loaded through one universal
loader routine called FURNSH (furnish), once there's an interface to
that routine, the door is wide open to add support for SPICE features.
, more like a new feature.