spacecraft orientation

[oldebirdAO7]

Greetings,

Today I have been struggling to change Jess LaFleur's AO7 3ds model to another more realistic orientation from its default at startup. Nothing I have tried to change or keywords added seem to work. I used Grant Hutchison's spreadsheet to convert a TLE to SSC ok and that appears to be correct. The SSC is where I have been trying various things found on the forum but to no obvious avail. What I want to do is change the spacecraft model default to point about 90 degrees from its current direction. Specifically, what I would like to do is 1) have the symmetic antennas (the long axis of the cylinder) to always point in the orbit plane (in the velocity vector direction is ok) and 2) then have the model rotate twice per orbit. I haven't been able to get it to budge from its initial orientation, however, which is my biggest problem. I would appreciate any insights or suggestions on appropriate keywords or other places to change the AO7 model orientation especially. Thank you very much.

[selden]

Could you provide the URL of the model?

While using Grant's spreadsheet is reasonable for objects with fixed orientations, you probably should use the new v1.5.0 Reference Frame parameters when orienting rotating objects. They're described in the Celestia WikiBook at http://en.wikibooks.org/wiki/Celestia/Reference_Frames

[BobHegwood]

Could you provide the URL of the model?

While using Grant's spreadsheet is reasonable for objects with fixed orientations, you probably should use the new v1.5.0 Reference Frame parameters when orienting rotating objects. They're described in the Celestia WikiBook at http://en.wikibooks.org/wiki/Celestia/Reference_Frames

Selden, I believe he's talking about the model HERE. It is one of the spacecraft available on the ML.

The SSC file follows:

Code: Select all

"1974-089B AMSAT Oscar 7" "Sol/Earth" {
  Class "spacecraft"
  Texture "panel.jpg"
  Mesh "amsat_oscar_7.3ds"
  Radius  0.003

 EllipticalOrbit {
    Epoch  2453041.45784790
    Period  0.07977227
    SemiMajorAxis  7827.733
    Eccentricity  0.0012465
    Inclination  101.7054
    AscendingNode  85.6605
    ArgOfPericenter  119.2153
   MeanAnomaly  241.0168
  }
  Obliquity  101.7054
  EquatorAscendingNode  85.6605
  RotationOffset  43.6051
  InfoURL "http://www.experthams.net/ao7"
}

Thanks, Brain-Dead

[selden]

By itself, the SSC file doesn't help: you have to discover the orientation of the model within its own coordinate system so you can decide which axes it needs to be rotated around.

[BobHegwood]

By itself, the SSC file doesn't help: you have to discover the orientation of the model within its own coordinate system so you can decide which axes it needs to be rotated around.

Just in case you missed it, I also provided a link to the model package itself in the above post.
Just trying to help. Will shut up now.

[Sky Pilot]

That reminds me of a related question that was discussed eons ago (before the latest improvements to Celestia's model orientation capability). Have the Pioneer models been updated so that the main antenna remain pointed at the Earth? If not, can that now be done??

Thanks
Sky Pilot

[qwerty182764]

Quick question -

Supposing I wanted to use Celestia to visualize the trajectory of a spacecraft that I have previously modelled in another program - I know about the XYZ files being used as lists of position with respect to the parent body - what about orientation? Is there an orientation list file that I can generate and load to do the attitude as well?

Thank you.

[selden]

Yes.

See the description of SampledOrientation, supported in Celestia v1.5.1 and later, at
http://en.wikibooks.org/wiki/Celestia/R ... rientation

[ElChristou]

That reminds me of a related question that was discussed eons ago (before the latest improvements to Celestia's model orientation capability). Have the Pioneer models been updated so that the main antenna remain pointed at the Earth? If not, can that now be done??

Thanks
Sky Pilot

Yep, if you have my Voyager addon, Voyager 2 have the main antenna pointed on Earth (I keep Voyager 1 old fashion). Just look at the ssc and you should be able to do the same for Pioneer...