question: placing a spacecraft

[Guest]

Is it possible to place a spacecraft in orbit around a moon? If so, how is the ssc written for that?

[granthutchison]

Here's Apollo 11 around Earth's Moon:

Code: Select all

"Apollo 11" "Sol/Earth/Moon"
{
   Class "spacecraft"
   Mesh "apollo.3ds"
   Radius 0.010

   EllipticalOrbit
   {
      Period 0.0873
      SemiMajorAxis 1922
      Eccentricity 0.00078
      Inclination 5
   }

   Albedo      0.10
}

Grant

[VF2_Rolf]

Celestia is one of the best planetarium programs ever...but it does not handle actual space flight very well. You might find Orbiter a likely companion to your Celestia install...actual space flight is its forte'. Orbiter had to play quite a bit of catch up to look as nice as Celestia...but that day has come. Also free.
http://www.medphys.ucl.ac.uk/~martins/orbit/orbit.html

Cheers,
Rolf

[Guest]

What if I wanted to add a spacecraft around an add-on moon, like Himalia that orbits Jupiter? I tried using the script posted above for that and it didn't work. Can a script be written for that?

[selden]

What if I wanted to add a spacecraft around an add-on moon, like Himalia that orbits Jupiter?

You would have to provide an SSC (Solar System Catalog) file describing the object and its orbit.

I tried using the script posted above for that and it didn't work.

Grant's example describes the orbit of Apollo 11 around the Earth's Moon.

You need to provide a model of Apollo 11 for it to be visible. (The Mesh line tells Celestia to load a 3DS model named "apollo".)

Since Celestia doesn't include that model, you can't see anything. Nevertheless, Celestia is faithfully calculating a new position for it every time it refreshes the screen.

Can a script be written for that?

Yes.

(Although it's a Catalog, not a script. Catalogs tell Celestia where things are. Scripts tell Celestia where to go and what to look at.)

You "just" have to provide a 3D model and the correct Keplerian orbital elements for the object that you want Celestia to draw.

Does this clarify things a little?

[selden]

So, anyhow, here's an SSC entry that will show a space probe that looks like Galileo in a non-physical orbit around Himalia. Its inertial thrusters are keeping it there

Code: Select all

"GuestProbe" "Sol/Jupiter/Himalia"
{
   Class "spacecraft"
   Mesh "galileo.3ds"
   Radius   0.01

   EllipticalOrbit
   {
   Period        4.4068
   SemiMajorAxis  463
   Eccentricity   0.831774
   Inclination    4.213
   AscendingNode  59.562
   ArgOfPericenter 97.224
   TrueAnomaly    -66.619
   }

   RotationPeriod    1.0e9
   Orientation     [ 90 0 1 0 ]

   Albedo         0.50
}


[JackHiggins]

Yup, you gotta love those inertial thrusters...

[VF2_Rolf]

"Yup, you gotta love those inertial thrusters..."

Yes indeed Himalia is almost impossible to orbit due to Jupiter's incredible influence...a gentle 'puff' from a lander's engine is all that is needed for lift-off...but it's a 'biggie' as far as Jupiter's outer moons go.

Speaking of thrusters...here's the USS-Discovery pulling into LMO. It is swinging around to point retograde for the capture burn. Happy New Year

http://www.flightsimnetwork.com/dcforum ... 36166.html

Cheers,
Rolf

[Guest]

I found the answer to my own question. I can't place a spacecraft in orbit around a moon in Celestia version 1.3.0, but I can in version 1.3.1.

[fsgregs]

Dear VF2_ROLF:

We have a model of Discovery available as an add-on in Celestia, but it does not have a good surface texture (it's mostly gray surface with no detail). Do you have a good detailed and textured model of Discovery available in 3ds format? If so, could you post it for downloading? If you don't have a website available, I can host it on mine if you e-mail it to me.

Regards,

Frank

[VF2_Rolf]

Frank,
That version of the USS Discovery can be found here...
http://homepages.nildram.co.uk/~dbartles/

...however it is for Orbiter and its meshes are no longer in 3DS format. Dave Bartles could be contacted to see if he has the mesh in 3DS...he also is the maker of the Leonov...


Both Leonov and the USS Discovery come with moving parts...the Discovery includes all 3 pods...working. Leonov has a deployable working airbag system for aerocapture though Jupiter's atmosphere.
Orbiter is on the verge of becoming a multiplayer network space flight simulator...check it out here...I've seen it in action...very impressive.
http://orbit.m6.net/v2/read.asp?id=12677

Cheers,
Rolf