chris wrote:I don't know what would be causing that . . . If you post your ssc file, I'll try and figure out what's going on.
I'm using this:
"spice_mgs" "Sol/Mars" {
Radius 0.01
Color [ 1 1 0]
Beginning "2006 11 02 00:00"
Ending "2006 12 01 00:00:00"
OrbitFrame {
EquatorJ2000 { Center "Sol/Mars" }
}
SpiceOrbit
{
Kernel "spk_m_061102-061201_mro-img_061117.bsp"
Target "-94" # MGS
Origin "4" # MARS BARYCENTER
BoundingRadius 1e32
Beginning "2006 11 12 00:00:00"
Ending "2006 12 01 00:00:00"
}
}
and
"spice_mro" "Sol/Mars" {
Radius 0.01
Color [ 1 1 0]
Beginning "2006 10 12 07:35:01"
Ending "2006 12 05 16:14:59"
OrbitFrame {
EquatorJ2000 { Center "Sol/Mars" }
}
SpiceOrbit
{
Kernel "spk_psp_rec00990_00986_01684_p-v1.bsp"
Target "-74" # MARS RECON ORBITER
Origin "4" # MARS BARYCENTER
BoundingRadius 1e32
Beginning "2006 10 12 07:35:01"
Ending "2006 12 05 16:14:59"
}
}
where I faked the begin and end times for the MGS file, being too lazy to read it out of the label. Maybe that's my problem, though I would expect it to not matter unless I set time outside that range.
Regarding reference frames for SPICE trajectories, I believe that it's defineable in the spk file, but EME2000 is typical. However, the SPICE functions to get a body's state vector at a particular time accept the name of a reference frame as a parameters. Celestia is always using "eclipj2000" right now, so you should match this by setting orbit frame to EclipticJ2000 in Celestia. I could provide a new property for SPICE trajectories that allows you to specify the name of a reference frame other than eclipj2000. It might be slightly more efficient, but I don't know if the additional flexibility would be otherwise useful . . . would it?
--Chris
Oh, OK. I always call SPICE stuff with "J2000" (which gets EME2000) as the reference frame. I don't see the extra flexibility as being useful, and it'd be nice if the SPICE files just worked without the need for an explicit reference callout.
This is a great resource; with a bit more work I might not have to use STK any more!