I am new to using SPICE and the SPICE Toolkit. My goal is to extract body radius, albedo, and distance from the sun of a number of solar system objects. The tools provided by NAIF are great and I have been able to get the information items I need from HORIZONS. I would like to use mice and the right selection of kernels to construct a table of body information. I am unable to locate the geometric albedo. It must be in there somewhere since HORIZONS reports it in its body summary (example below). Please point me to which kernel(s) the information in the example is extracted from.

Horizons> 500

JPL/HORIZONS 500 Selinur (1903 LA) 2018-Apr-26 15:32:09 Rec #: 500 (+COV) Soln.date: 2018-Apr-05_11:16:59 # obs: 1803 (1903-2018)

IAU76/J2000 helio. ecliptic osc. elements (au, days, deg., period=Julian yrs):

EPOCH= 2455485.5 ! 2010-Oct-16.00 (TDB) Residual RMS= .28963
EC= .1453222754778464 QR= 2.232822954662918 TP= 2455876.0720004463
OM= 290.0072894804399 W= 75.13840817439457 IN= 9.764544808931515
A= 2.612473556522465 MA= 268.8351702646443 ADIST= 2.992124158382012
PER= 4.22266 N= .233413627 ANGMOM= .02750885
DAN= 2.46541 DDN= 2.65631 L= 4.9371039
B= 9.434865500000001 MOID= 1.25316 TP= 2011-Nov-10.5720004463

Asteroid physical parameters (km, seconds, rotational period in hours):
GM= n.a. RAD= 20.414 ROTPER= 8.0111
H= 9.3 G= .150 B-V= n.a.
ALBEDO= .202 STYP= n.a.

ASTEROID comments: 1: soln ref.= JPL#41, OCC=0 2: source=ORB

Select ... [A]pproaches, [E]phemeris, [F]tp,[M]ail,[R]edisplay, [S]PK,?,:

  • $\begingroup$ In this context, what is SPICE? Can you provide a link to it? $\endgroup$
    – user10106
    Apr 27 '18 at 14:18
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    $\begingroup$ Information on SPICE can be found at naif.jpl.nasa.gov/naif/toolkit.html $\endgroup$
    – Ames
    Apr 27 '18 at 15:59
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    $\begingroup$ This is unhelpful, but if you go to ssd.jpl.nasa.gov/sbdb.cgi and type in "selinur", it takes you to a page with Selinur's albedo, citing "JPL 41". The BSP files in naif.jpl.nasa.gov/pub/naif/generic_kernels/spk/asteroids may or may not be helpful. You may also ask on the SPICE discussion list at spice_discussion@naif.jpl.nasa.gov $\endgroup$
    – user21
    Apr 29 '18 at 4:04
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    $\begingroup$ @MikeG Feel free to add it as one, but now I'm wondering if body variables such as albedo may not be stored in the SPK files. $\endgroup$
    – user21
    May 2 '18 at 15:28
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    $\begingroup$ @barrycarter thanks for the "write your own SPK" idea, it seems a PCK kernel is appropriate for body physical properties, I am considering that as a possible solution once I've build the set of data I want ready access to. The NASA HORIZONS System [link] ssd.jpl.nasa.gov/?horizons has batch interfaces via email and telnet. I'm working on a bulk query/download through HORIZONS, extracting the data from the output and building a PCK kernel. $\endgroup$
    – Ames
    May 9 '18 at 12:17

As barrycarter commented, codes_300ast_20100725 has ephemerides for 300 large asteroids, generated in 2010 and supposedly valid from 1800 to 2199. For other asteroids, a Celestia developer forum shows how to how to request an SPK from HORIZONS's telnet interface. However, they appear to use the SPK for ephemeris only, adding albedo in Celestia's own SSC file format. In SPICE documentation, neither the tutorials nor the "required reading" seems to mention albedo.

A more direct approach to your goal might be the JPL Small Body Database Search Engine. For example, if you query for numbered NEO asteroids with absolute magnitude H < 16, you get a table of 169 rows. Diameter and albedo are known for some asteroids but not others, even though their orbits and rotational periods may be well established.


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