Can't access JPL Horizons state vectors for Deep Impact impactor

[BrianJ]

Hi,
I've been trying to get the state vectors for the Deep Impact (Impactor) spacecraft from Horizons without success - I just get a an error message saying "insufficient data loaded to generate ephemeris....."[etc]

I've tried it every which way I can think of, using the web interface and telnet.

Can anyone help me out and grab the state vectors for the Impactor at
2005 Jul 04 05:40:00 (~5 mins before impact) ?

Spacecraft ID is -70
centre object is @sun

Many thanks,
Brian

P.S. Might be a bug at Horizons I guess, but I'd like confirmation that it's not just me before I bother them with an email.

 

[tblaxland]

 Files merged in Horizons to provide time-continuous trajectory data:
 Trajectory Name               Start (CT)            Stop (CT)
 ----------------------------- --------------------  --------------------
 dif_preenc174_nav_v1          2005 JAN 12 19:23:32  2005 JUN 01 00:00:00
 di_imp-od169                  2005 JUN 01 00:00:00  2005 JUL 03 06:16:05
 [B][COLOR="Red"]di_finalenc_nav_v3_to06048    2005 JUL 03 06:16:04  2005 JUL 05 05:45:34[/COLOR][/B]

Any query requiring access to that highlighted ephemeris file fails for me. Up to 2005-Jul-03 06:16:05 works no problem though.

 

[BrianJ]

Many thanks TB Not just me, then.

I'm pretty sure that last ephemeris file is the post-seperation data - which is what I want.

I think I'll drop them a line about it.

Cheers,
Brian

 

[Ajaja]

BrianJ
For Orbiter, MJD 53555.2361204175:

DEEP IMPACT IMPACTOR SPACECRAFT (-70):

  STATUS Orbiting Sun
  RPOS -87677373448.5129700000 1342139709.1339679000 -207560947700.5499900000
  RVEL 18425.6143400189 -109.7969736431 -12745.0399791712

TEMPEL 1 (1000093):

  STATUS Orbiting Sun
  RPOS -87680305911.8890990000 1343946287.2843294000 -207561418074.0242600000
  RVEL 27112.3373400189 -5461.3518867726 -11351.6702777966

 

[BrianJ]

Excellent! Thanks so much

How did you get the vectors? Horizons still won't let me have 'em :-(
The only thing I didn't try was requesting the data via email (I've always used telnet or, these days, the web interface)

Well, at least I can update the "5 mins to impact" scenario in my old Deep Impact add-on now.

Thanks again.

Regards,
Brian

 

[Ajaja]

How did you get the vectors? Horizons still won't let me have 'em :-(

SPICE library http://naif.pds.nasa.gov/ , kernels from ftp://naif.jpl.nasa.gov/pub/naif/DEEPIMPACT/kernels/spk and a very simple program:

#include <stdio.h>
#include <string.h>
#include "SpiceUsr.h"

int main(int argc, char* argv[])
{
  const SpiceInt body_id=-70;
  const SpiceInt origin_id=10;
  const double mjd = 53555.2361204175;
  const double t=(mjd-51544.5)*86400.0;
  double state[6];
  double r[6];
  double lt = 0.0;
  remove( "SPICE.ERR" );
  errdev_c ( "SET", 1024, "SPICE.ERR" );
  errprt_c ( "SET", 1024, "ALL" );
  erract_c ( "SET", 1024,"REPORT" );
  furnsh_c("E:\\Games\\Orbiter\\Kernels\\de421.bsp");
  furnsh_c("E:\\Games\\Orbiter\\Kernels\\di_finalenc_nav_v3.bsp");
  spkgeo_c ( body_id, t, "ECLIPJ2000", origin_id, state,  &lt);
  r[0]=state[0]*1000.0; r[2]=state[1]*1000.0; r[1]=state[2]*1000.0;
  r[3]=state[3]*1000.0; r[5]=state[4]*1000.0; r[4]=state[5]*1000.0;
  printf("Date MJD %.10lf\n",mjd);
  puts("STATUS Orbiting Sun");
  printf("RPOS %.10lf %.10lf %.10lf\n",r[0],r[1],r[2]);
  printf("RVEL %.10lf %.10lf %.10lf\n",r[3],r[4],r[5]);
  return 0;
}

 

[BrianJ]

Awesome! I'll see if I can compile your code and get it working for me. I wonder if the Spice->Orbiter utility on OH still works with Orbiter2010-P1 ? ...I'll have to take a look.

Thanks :thumbup:

 

[Ajaja]

Awesome! I'll see if I can compile your code and get it working for me. I wonder if the Spice->Orbiter utility on OH still works with Orbiter2010-P1 ? ...I'll have to take a look.

Latest version for Orbiter2010 here:
http://orbiter-forum.com/showthread.php?t=1387

BTW. Mayby, for Deep Impact its really better to take di_finalenc_nav_v3_to06048.bsp as Horizons do, but not di_finalenc_nav_v3.bsp as I did.
ftp://naif.jpl.nasa.gov/pub/naif/DEEPIMPACT/kernels/spk/aareadme.txt

NOTE 4: The following four of these SPKs should be loaded in
this order to make sure that the best trajectory solutions are
available to the calling application at any given time:

dii_preenc174_nav_v1.bsp
dif_preenc174_nav_v1.bsp
di_tempel1_ssd_v1.bsp
di_finalenc_nav_v3_to2006048.bsp

  furnsh_c("de421.bsp");
  furnsh_c("dii_preenc174_nav_v1.bsp");
  furnsh_c("dif_preenc174_nav_v1.bsp");
  furnsh_c("di_tempel1_ssd_v1.bsp");
  furnsh_c("di_finalenc_nav_v3_to06048.bsp");
  furnsh_c("di_v17.tf");
  furnsh_c("di_tempel1_v01.tpc");

Vectors ( Date MJD 53555.2361204175):

RPOS -87677373355.5939480000 1342138027.8839767000 -207560945527.5875900000
RVEL 18425.5134351540 -109.7862636565 -12745.0273778736

  RPOS -87680305444.6891170000 1343946093.7077255000 -207561418223.3463700000
  RVEL 27112.3373400189 -5461.3518867726 -11351.6702777966