Re: The small "moons"

[XonE32]

Re: The small "moons"

I suppose this comes under the heading of the "outer planets" add-on.

K so I just took my first trip out to Neptune with the Deepstar2 and 2 DGIV's attached. Set up a nice Orbit at approx 22.00M. This put me within close reach of Despina, Naiad, Thalassa and not too far from Galatea. So I thought I'd go touring.

Now I only went to Galatea before I realized there's a prob. I don't think any of these "moons" have .dll's but of course they all have .cfg's. Based on their size/mass you'd think you'd be able to land on em, but when I tried I got sucked off... hmm, that sounds rude, but oh well.

My question is: Do these small rocks need proper .dll's for them to "work" (i.e be able to land on and stay grounded) or can one just adjust the mass settings in the .cfg to create enough gravity to keep you grounded on the surface? I assume they need a .dll.

According to NASA...

http://solarsystem.nasa.gov/planets/profile.cfm?Object=Nep_Galatea&Display=Facts&System=Metric

One would think that something this big would have the gravity to keep a DGIV grounded or am I way off here? I could see Neptune's gravitational pull being a factor, but although Galatea is just a tiny boulder in space it's still pretty big compared to a DGIV. If it's just a .cfg edit then yay, if I have to make a .dll for 'em then I guess I'm screwjied.

Thanks for any input in advance

Regards

XonE 32

 

[tblaxland]

I get a gravitational acceleration on the surface of Galatea of about 0.02m/s/s so your DGIV would only be subjected to a force of about 500N. I think it would be pretty hard to land there with out bouncing off, obviously your experience.

You can change the mass of the moon in its cfg file. Just look for the line starting with "Mass ="

 

[VF2_Rolf]

Indeed, the masses picked were often just 'educated' guesses. Feel free to adjust.

 

[XonE32]

Thanks for replying guys, it is really appreciated.

Don't take this the wrong way as it may sound like a dickish response when typed... it's not, I'm just curious and wanted clarification.

The question I asked wasn't answered specifically (i.e re: .dll's and .cfg's) so I just wanted to be clear as it it does sound like your both saying the same thing...

i.e. that all I need to do is edit the .cfg's mass a bit and that will indeed affect the ships performance when close to the moon. And that conversely (and more importantly), I do NOT need to create a specific .dll for the object to achieve this effect. Is that correct?

I hope so, 'cause me no know how do .dll. UNK!

Regards

XonE 32

 

[Bj]

i.e. that all I need to do is edit the .cfg's mass a bit and that will indeed affect the ships performance when close to the moon.

All you need to edit under the .cfg is;

Mass = 5.973698968e+24 //earths mass

If you changed earths mass to 5.973698968e+1 then its like turning off gravity.

 

[XonE32]

That's great BJ. Glad it's just a .cfg edit.

Now to find the best info on the rocks... pfft good luck.

If ya look at NASA's site and look at their specs for these rocks one gets the impression of a bunch of scientists throwing darts at a "mass board" to come up with the figures. At least 3 or so of Neptune's moons are listed with the same mass of 800,000,000,000,000,000 kg.

One can see how poor Rolf had to make those educated guesses.

Regards

XonE 32

 

[Bj]

If your planning on making your own planet this might help.
Quoted from spaceranger

but besides that I'm not really sure what your trying to accomplish.
http://orbit.m6.net/Forum/default.aspx?g=posts&t=4531

A planet or moon (or star for that matter) are all referenced in a system .cfg file (located in the Config directory beneath the Orbiter root program folder), and detailed in an individual .cfg file for each star/planet/moon.

For example, the system .cfg file for the default solar system (ours) is Sol.cfg. It references the star (Sun, or really Sun.cfg) and all the other planetary, moon, and asteroid .cfg files by name (the .cfg extension is not used in the list, however, just the name).

Each of the .cfg files for the star/planets/moons/asteroids (if you have any) detail the physical and orbital elements of an individual celestial object. The solar system objects (or most of them anyway) that come with Orbiter use custom .dlls to generate the orbital elements. Earth, the Moon, etc. all have a .dll that tells Orbiter how the object will move. This is the most accurate way to do this, but you don't have to write a .dll. You can just put the orbital elements into the planet/moon .cfg file directly, and then Orbiter will process that information to calculate the orbit. It's less accurate, but works.

The Orbiter documentation and the SDK documentation go into detail on how to edit the .cfg files, and what the parameters mean.

You can download textures from NASA or something from the web, if you want to detail an existing solar system object that there are images for. There's links to resources on the Orbiter main site and elsewhere, just google around and you'll find some.

If you want a custom texture (and who doesn't) you'll have to either make your own or use something like the LunarCell plugin for Photoshop (google for it). LunarCell has a free demo period, and makes passable textures that are of the correct proportions for Orbiter to use (check the manuals for the pixel dimensions, the texture images should be twice as wide as they are tall), but you have to have Photoshop to use it. It can do some handy things like generate cloud layers (to use seperately from planet/moon textures, allowing the clouds to move independent of the planet) and land/sea masks (so that the water areas reflect specular light but the land areas do not). Having a cloud layer and land/sea masking is key to making a realistic planet texture.

You can also take pictures of real world textures (like rock facings for moon/asteroid textures) and manipulate them and save them as 8-bit or 24-bit bitmap files. This can be somewhat arduous.

There's a free landscape generating program called Terragen that can probably produce very detailed planet/moon textures, but you'd have to get good at it to do so. I'm still tinkering with it.

There's something called Fractal Landscapes or Fractal Explorer that I believe can generate planetary image files you could convert to Orbiter textures as well, but you must buy the software.

Once you have bitmap files of the correct pixel size and dimensions, you can use the Orbiter SDK utility, pltex, to convert the .bmp files to Orbiter .tex files.

With the surface texture files and a config file with a reference to the planet .cfg file name in the system .cfg file, you can bring your custom celestial object into Orbiter.

A detailed, step-by-step approach is too long for me to go in here, but download the Abu and/or Eru custom star systems from Orbiter Hanger Mods and you can see how other folks have done it (without using custom .dlls).

I've almost nearly finished developing a custom star system (for the Firefly Jumbo mod) and it's been tons of fun. I went in cold and learned a lot, took some time though. What I really want to do now is figure out if it is possible to dynamically load one scenario file from another, and populate orbital elements/time/etc from the first (running) scenario file into the scenario file being loade. Wish me luck .. ;^)

 

[XonE32]

No no, not planning on making my own planets or anything. I was just surprised that I couldn't land on Galatea and stay landed. So I wanted to see if I could change the mass in the .cfg to accomplish a landing OR did I have to go and make a .dll which I don't know how to do.

Most of my touring has been done in the inner planets and Jupiter where the moons that I've been to are larger and the one small one I go to often (Amalthea) has PreludeII base on it. In other words I hadn't encountered a situation where I couldn't land on an object and stay landed... till now.

But thanks for the post it's an interesting read.

Regards

XonE 32


EDIT: added quote

...but you don't have to write a .dll. You can just put the orbital elements into the planet/moon .cfg file directly, and then Orbiter will process that information to calculate the orbit. It's less accurate, but works.

This was the info I was looking for. Basically a confirmation. I dind't want to go messing about with Rolf's .cfg's until I new it would have an effect.

 

[Linguofreak]

Keep in mind that all we have to estimate the masses of those moons by are observations from Earth and one flyby by Voyager 2. Neptune is 30 AU away, and these moons are very small, in fact, none of the ones you mentioned were even discovered until Voyager made its flyby. We don't even have clear photos of them, let alone a good idea of their mass.

But still, the one thing that is certain is that their masses are small enough that they don't have much gravity at all. The behavior you got was probably correct.

 

[XonE32]

Keep in mind that all we have to estimate the masses of those moons by are observations from Earth and one flyby by Voyager 2. Neptune is 30 AU away, and these moons are very small, in fact, none of the ones you mentioned were even discovered until Voyager made its flyby. We don't even have clear photos of them, let alone a good idea of their mass.

But still, the one thing that is certain is that their masses are small enough that they don't have much gravity at all. The behavior you got was probably correct.

Agreed.

I was just thinking of putting in NASA's est. mass for a couple of em and see if there's any change (e.g. those above 120km diameter) like Galatea, Despina, Larissa and Proteus. But I'm going to check what happens on each with the current .cfg's first.


-----Posted Added-----


After testing

Example Galatea: Although Rolf's est Mass (59,550,000,000,000,000 kg) is lower than NASA's est Mass (800,000,000,000,000,000 kg); the result is much the same. You won't fly off into space with NASA's est mass unless you land "well" (0 lateral motion). It's hard as hell to get a stable landing that lasts. Other wise ya just bump along the surface. But if done well you'll get a landing that lasts even under time compression.

Anyone up for making a "harpoon" mod for the DGIV :lol:. I suppose I could put yet another PreludeII into the scenario.