Placing a ship in deep space independent of a solar system

[Reiko]

Is there a way to place a ship or space station in deep space that is not part of a solar system?
The only way I have been able to do it is make it a nebula but then it glows.

[fungun]

How about a barrycenter?
Wouldn't that work? Then give it a very long orbital period.
Tim

[selden]

Reiko,

Unfortunately, a non-glowing object has to be associated with a Star or Barycenter. Celestia really wasn't designed to depict travel between stars.

As Tim mentions, though, you can associate an SSC object with a Barycenter.

I'm still not sure if Celestia will draw the spacecraft, though, since it wouldn't be associated with anything that would illuminate it. Alternatively, you could just put it on a very long elliptical orbit around its home Star, and which just happens to loop around some other non-moving destination Star. I suspect the spacecraft still wouldn't be illuminated by the destination Star if that Star is defined separately. I'm sure Celestia only draws the illumination that's provided by Stars in an SSC object's parent Star system -- Stars that are defined to orbit around one another or around Barycenters.

Another limitation is that Celestia only draws SSC objects when the viewpoint is less than 1 LY from the parent Star.

One possibility might be to simulate the spacecraft's spacedrive by a very tiny star. I had some trouble with that aproach when I tried it some time ago, but maybe I just didn't try hard enough.

I hope these thoughts help a little.

[Reiko]

Thank you for the help guys, I will give those ideas a try.

[selden]

Here's a very quick hack:
a blue Bussard spacecraft in deep space


(this links to a bigger image)

[eburacum45]

Nice ramscoop, Selden!


a few questions...
Is this based on a particular design study?
what is the blue ovoid? Is that the payload? If not, where would the payload go?
Which way is it travelling?
Can we have a copy?

[selden]

This isn't based on any design study. It's just a "proof of principle" that one can persuade Celestia to display an interstellar spacecraft if it's associated with a Star used to simulate its fusion drive.

(I didn't do it with this one, but...
Stars can orbit around Barycenters. You can define a Barycenter to be anywhere, including the Galactic Center. You can define the Star's orbit to have any size of SemiMajorAxis in units of AU, including large enough to be circling the Galactic Center at the distance of our Sun. Since the SMA is expressed in double precision, I think it'd place the Star reasonably accurately.)

It's travelling toward the upper right.

The white, speckled ovoid represents the fusing hydrogen. (It's an STC Star with SemiAxes [ 1 0.2 0.2 ] )

The blue ovoid represents the spacecraft.
(It's an SSC spheroid with Oblateness -0.45 and placed at a FixedPosition relative to the Star)

The green lines represent the magnetic field.
(That's a model of a distorted torus, with all surfaces first indented and then those indents deleted.)

I'm really not sure why you'd want this one: it's rather shoddy and it took about 15 minutes to create. I can't provide it tonight, anyhow: it's on my system at work and I'm at home and don't feel like recreating it now. Tomorrow.

[eburacum45]

It looks like it could have distinct possibilities.

[selden]

The crude bussard model is now available at
http://www.lepp.cornell.edu/~seb/celest ... ussard.zip (700KB)
The readme, ssc and stc files include comments suggesting how it could be modified.

[eburacum45]

Thanks; I'm sure that will be useful.

[Tuefish]

You could Make a new star for the engine(or equivalent) then, no matter where the ship is, it would be, Technically around a star. It might work.

[eburacum45]

This is what I've got so far.

This ship is a hybrid, using the ramscoop to gather propellant but not for fusion. The fuel is contained in the tanks; basically a RAIR (or perhaps a catalysed RAIR) ship.
http://www.daviddarling.info/encycloped ... amjet.html

The beam coming out of the back is a 'killing star' mesh from OA; I've changed the drive to a white dwarf, by the way.

[selden]

A minor quibble: I would expect the fuel scoop to have to be much bigger -- possibly multiple km across, although that's probably impractical for modelling.

[eburacum45]

The magnetic field itself would be bigger- I have used your mesh in a different way, to represent the structures holding the superconducting loops which generate the field. Perhaps the loops need to be bigger too. I see that according to David Darling's sources, the reaction chamber itself need only be 3.5 metres across in an antimatter design, which would be vanishingly small compared to the scoop.

Perhaps one of Cham's magnetic field line models might better represent the magnetic scoop itself.

[Reiko]

Reiko,

Unfortunately, a non-glowing object has to be associated with a Star or Barycenter. Celestia really wasn't designed to depict travel between stars.

As Tim mentions, though, you can associate an SSC object with a Barycenter.

I'm still not sure if Celestia will draw the spacecraft, though, since it wouldn't be associated with anything that would illuminate it. Alternatively, you could just put it on a very long elliptical orbit around its home Star, and which just happens to loop around some other non-moving destination Star. I suspect the spacecraft still wouldn't be illuminated by the destination Star if that Star is defined separately. I'm sure Celestia only draws the illumination that's provided by Stars in an SSC object's parent Star system -- Stars that are defined to orbit around one another or around Barycenters.

Another limitation is that Celestia only draws SSC objects when the viewpoint is less than 1 LY from the parent Star.

One possibility might be to simulate the spacecraft's spacedrive by a very tiny star. I had some trouble with that aproach when I tried it some time ago, but maybe I just didn't try hard enough.

I hope these thoughts help a little.

Sorry to dig up this old thread but I still can't seem to make this happen. Placing an SSC object around a barycenter with no star present causes celestia to crash every time you try to select the SSC object.
What I was wanting to do is place a starbase out in interstellar space and have the only illumination come from its own emissivemaps.

Is there maybe a way to create a star that emits no light? Like a black hole star or something?

[selden]

Placing an SSC object around a barycenter with no star present causes celestia to crash every time you try to select the SSC object.

When Celestia crashes, it's a bug and needs to be reported.

I managed to duplicate this crash in the latest SVN code (r4544 built on XP with VS Express 2005) by defining a planet around a barycenter.

What I was wanting to do is place a starbase out in interstellar space and have the only illumination come from its own emissivemaps.

Remember that emmisivemaps do not provide any illumination. They only glow as themselves.
They won't light up the structures around them.

Is there maybe a way to create a star that emits no light? Like a black hole star or something?

You can define a very dim star by specifying a low AbsMag, but that doesn't work either.
As best I can tell, Celestia cannot currently do what you want.
If there's not enough external light, it does not draw the object at all. (I don't know how much is "enough")

As a test, I defined a star with an AbsMag of 50. I could GoTo the star and see it, and I could GoTo the position of a planet orbiting around it, but the planet was not drawn and its "selected" marker wasn't drawn, either.
Again, this was with Celestia r4544.

For the moment, I think you'll have to simulate it by a tiny star and a very dark surface texture on your station

[Reiko]

Hey your idea works! I made a very dim star and placed the object about 99 AUs out. From that distance you can't see the star and with the diffuse levels set to 0 0 0 in the model, it isn't illuminated by the star.

Here is the result.



Perfect! Thanks selden.

[selden]

Reiko,

You're very welcome, of course.
I reported the crash in Celestia's SourceForge bug tracker.

[Hungry4info]

Is there maybe a way to create a star that emits no light? Like a black hole star or something?

Make a T9V star (Such a late spectral type is drawn without an atmosphere or flare).

Give it a mesh that just happens to not exist.

[Reiko]

Is there maybe a way to create a star that emits no light? Like a black hole star or something?

Make a T9V star (Such a late spectral type is drawn without an atmosphere or flare).

Give it a mesh that just happens to not exist.

I don't know what a T9V star is.