solar system blues

[DocHoliday]

Hey Freespace

I checked out the scenario. Damn, that's some weird stuff. I didn't have much time to work on it, but why did you
make the planets so small and light?

It seems to me, that Orbiter processes planets differently than objects. That's nothing new, it's been discussed
before, but it looks as if for a planet, you set the orbital parameters and then Orbiter computes the necessary orbital
velocity, to keep it AT THAT distance. Seems to me, if you set up a planet with a suicide orbit, that would spiral
towards the central body, it actually won't because orbiter will increase it's orbital velocity to prevent it. It makes
sense. Planetary orbits are then fixed, which means, less computation power if you can just ignore the various
perturbations and concentrate on vessels alone.

So this seems to be the case with your two moons. I'll read Gene's tutorials on this subject and try to see where the
trick is, BTW thanks very much for you work Gene! On the other hand, you have another planet, I think it was the first
one, which has a very small moon, VERY close to the surface and the moon barely moves...

A puzzled cheers,

[freespace2dotcom]

Did I not say earlier that the first words out a anybody's mouths when they see the first planet would be "wtf"? (read
up) I just wanted to go with something really wild. It's more fun. I made the first planet small because I wanted the
star's gravity to dominate the area.  furthermore, I think it'll make some nice screenshots having the moon so close to
it, though I'll likely put it back up a few reasonable notches.  I don't think myself that anything is really wrong, with
the exception of the the rapidly spinning problem.  Also, remember that the *really* small "planet"  that is about the
size of the shuttle is only a place holder, at least until I can find another way around to get what I want to do.. but
other than that, there aren't any small planets. What your saying makes sense, so I'll probably fundamentally change
the "spiralling planets" idea or abandon it for now... most likely the first option.. I'll have time to think about it during
the weekend, I guess.

[DocHoliday]

I know I know

Ah, so your idea depends on the two planets spiraling down on eachother. I'll also think about it.. It may happen that
you will have to actually disguise the planets as vessels for Orbiter to interpret them as you want. Sort of like two
Death Stars near eachother. They should be heavy enough to produce some kind of attraction force.

Cheers,

[freespace2dotcom]

OK, what now? I'm afraid you lost me here... Yeah, I want to have the planets that rotate around that "place holder"
do exactly what they are doing but much slower. I'm afraid that I don't follow you past that. I didn't know that you
could 'disguise' planets in such a manner, and it doesn't seem logical to me that vessels would attract each other in
orbiter. Sure in real life mass attracts more mass. Even in minute proportions, but if vessels were designed to have
this "attraction" even in correct proportions, that seems like a nightmare to code. So much so, I would think that that
it would be easier to just say that vessels don't have this attraction factor, and planets only have the ability to pull
something to it. Of course I have no idea how it really is, but it seems logical to me, because if you have the code
wrong, then something like docking to the iss would become a pain because of possible atractions. and even if it was
right, what would make a vessel attract better than a planet's gravity? Because 1 ton from a planet weighs just as
much as 1 ton from a vessel, I don't see how anything would change.. OK my ears are ringing from all the
thinking.. let me know what you think..

[DocHoliday]

Okay the way I see it. I would appreciate some input from Dan or another Orbiter intimate conaisseur, because I am
guessing here:
1. You want to planets to spin around eachother in a degrading orbit?
2. Assuming Orbiter doesn't support that, the two planets would just orbit the star, side by side, never getting into a
spin around eachother. I presume, this is why you have to use the third, central planet, to induce the spin. That
would be consistent with what I said before. The orbital planets are not taken into calculation on a micro level, such
as mutual close attractions (with the exception of being designated as moons). Only macro level - orbit around a
single star. I seem to recall reading on some thread in the main forum, that Orbiter only supports up to three body
attraction (Star-planet-moon). So if you designate them as such, they stay such. A moon cannot have a moon and
twin planets also would not work. I wonder how Pluto and Charon are solved then??? Being almost equal size, they
should spin around eachother.
3. Again under the assumption that the vessel are treated differently (which I doubt), you could set the two planets
as vessels, both with a planetary mass, which would induce equal gravity. If gravity is not taken into consideration as
a funcion of mass and density of the vessels, that the idea doesn't work. But if they are, the ISS also attracts you,
BUT the attraction compared to Earth mass in the vicinity is negligable. Were the ISS to weight something in the order
of 10e+20kg, that would be quite noticable.

See what I mean?

Now the questions remain:
1. Can the planets affect eachothers orbits?
2. Can vessel have gravitational force as a function of mass?

Dan?

If both answers are negative, you can't do a spiral orbit twin-planet system. Only fixed orbit around a central
(invisible) planet-which for sake of storytelling could be called a small black hole or whatever. Either way, the
gravitation from this planet would change the navigation of a vessel around the two planet moons. You would do
slingshots around the central planet, instead of directly traveling from one planet-moon's SOI to another.

I'm spent I need to test all this, becaues I feel like a dogma preacher now

[freespace2dotcom]

DocHoliday wrote:

> Okay the way I see it. I would appreciate some input from Dan
> or another Orbiter intimate conaisseur, because I am
> guessing here:
> 1. You want to planets to spin around eachother in a degrading
> orbit?

Define degrading. I just want them to spin around each other. I don't want them to eventually crash into each other,
which is my perception of that word.

> 2. Assuming Orbiter doesn't support that, the two planets would
> just orbit the star, side by side, never getting into a
> spin around eachother. I presume, this is why you have to use
> the third, central planet, to induce the spin. That
> would be consistent with what I said before.

I'm assuming that orbiter doesn't, which I'm 99.9% certain of now judging by what others have said previously, and
that IS why I made that central planet. to make them revolve around each other.

The orbital
> planets are not taken into calculation on a micro level, such
> as mutual close attractions (with the exception of being
> designated as moons). Only macro level - orbit around a
> single star. I seem to recall reading on some thread in the
> main forum, that Orbiter only supports up to three body
> attraction (Star-planet-moon). So if you designate them as
> such, they stay such.

I follow you so far

 A moon cannot have a moon and
> twin planets also would not work. I wonder how Pluto and Charon
> are solved then??? Being almost equal size, they
> should spin around eachother.

that could be why pluto isn't in the orbiter solar system. Last I looked it wasn't there...

> 3. Again under the assumption that the vessel are treated
> differently (which I doubt), you could set the two planets
> as vessels, both with a planetary mass, which would induce
> equal gravity. If gravity is not taken into consideration as
> a funcion of mass and density of the vessels, that the idea
> doesn't work. But if they are, the ISS also attracts you,
> BUT the attraction compared to Earth mass in the vicinity is
> negligable. Were the ISS to weight something in the order
> of 10e+20kg, that would be quite noticable.
>
> See what I mean?
>
I do, HOWEVER! let's assume both a ship and the iss are right next to each other, moving in parallel right next to
each other. both have identical relative velocity compared to the planet.
earth's massive gravity would cancel out, and the iss would theoretically attract that ship. a simple example formula
(not intended for real life) would be X/Z=Y/Z (x divided by z equals y divided by z)

Where X is the ship's gravity and Y is the iss's, while Z is earth's.

Using simple algrebra, you can multiply both sides by Z and that gets rid of the earth's gravity from the equation, but
the thing is, the value of the equation stays the same. It could theoretically make problems in docking.. now if you
didn't have identical relative velocity, then yeah, the iss's attraction really couldn't do anything

Keep in mind that's only an example, I don't have the brainpower to come up with a real working formula, I just
wanted to show that they cancel out. (at least If I'm right, which I'm just guessing myself, but it seems right from my
point of view....)

> Now the questions remain:
> 1. Can the planets affect eachothers orbits?
I know that Jupiter affects mar's orbit at least a little in real life, and but programming THAT realistically would
probably take years for even a microsoft budget team to do.

> 2. Can vessel have gravitational force as a function of mass?

I dunno that one.

>
> Dan?
>
> If both answers are negative, you can't do a spiral orbit
> twin-planet system. Only fixed orbit around a central
> (invisible) planet-which for sake of storytelling could be
> called a small black hole or whatever. Either way, the
> gravitation from this planet would change the navigation of a
> vessel around the two planet moons. You would do
> slingshots around the central planet, instead of directly
> traveling from one planet-moon's SOI to another.
>
*thinking*

> I'm spent I need to test all this, becaues I feel like a
> dogma preacher now
I hear you.

[DocHoliday]

> Define degrading. I just want them to spin around each other. I
> don't want them to eventually crash into each other,
> which is my perception of that word.
Ah, then you don't need degrading. With degrading I meant, that the planets are going to in time collide or slingshot
around eachother in permanent hyperbolic orbits.

> I'm assuming that orbiter doesn't, which I'm 99.9% certain of
> now judging by what others have said previously, and
> that IS why I made that central planet. to make them revolve
> around each other.
Ok, question answered.

> that could be why pluto isn't in the orbiter solar system. Last
> I looked it wasn't there...
I know. But there is an addon, or rather was for one of the previous versions for outter planets. Maybe you should
find it and see how they dealth with the problem. I distinctly remember Pluto also being there, but I've always been
more interested in vessels and stations more than bases, planets and systems.

> earth's massive gravity would cancel out, and the iss would
> theoretically attract that ship. a simple example formula
> (not intended for real life) would be X/Z=Y/Z (x divided by z
> equals y divided by z)
I quite agree. But it might take months to register any kind of acceleration or velocity to be sure. For practical
purposes of docking where relative velocities are very high compared to the attraction acceleration factors, that again
doesn' present a problem.

> Keep in mind that's only an example, I don't have the
> brainpower to come up with a real working formula, I just
> wanted to show that they cancel out. (at least If I'm right,
> which I'm just guessing myself, but it seems right from my
> point of view....)
Me too. I do remember the logic is quite simple though.

> real life, and but programming THAT realistically would
> probably take years for even a microsoft budget team to do.
Agreed. Not to mention the kind of processor you would need to compute it in real-time simulation.

> > 2. Can vessel have gravitational force as a function of
> mass?
> I dunno that one.
I'll try it with the Death Star addon. That bitch should be heavy enough to exibit some kind of attration at least on
10000x compression.

> > vessel around the two planet moons. You would do
> > slingshots around the central planet, instead of directly
> > traveling from one planet-moon's SOI to another.
> >
> *thinking*
Forget that. We've established you only need a normal orbit. I don't see a problem then. You managed to set up a
few planets with moons. This particular one should be similar then. Just use moon sized bodies at least. Makes things
more intuitive

Hope I can try some of this out over the weekend.

Cheers,

[freespace2dotcom]

DocHoliday wrote:


> Ah, then you don't need degrading. With degrading I meant, that
> the planets are going to in time collide or slingshot
> around eachother in permanent hyperbolic orbits.
>
I know that the planets rotate around each other very fast, which is why you probably thought that. but it's not
intentional, I'm gonna find a way to slow them down for sure.. They're WAY too fast, you know?

Also, I didn't give the "place holder" planet any real mass at all, so it's gravity is negligable, no need for slingshots
around it, am I right?


> I know. But there is an addon, or rather was for one of the
> previous versions for outter planets. Maybe you should
> find it and see how they dealth with the problem. I distinctly
> remember Pluto also being there, but I've always been
> more interested in vessels and stations more than bases,
> planets and systems.

I'll start hunting for it. more if/when I find it.


> I quite agree. But it might take months to register any kind of
> acceleration or velocity to be sure. For practical
> purposes of docking where relative velocities are very high
> compared to the attraction acceleration factors, that again
> doesn' present a problem.

True, true.. I just wanted to present my point. It really doesn't matter, but because it doesn't matter, I really don't
think orbiter was programed for vessels to have gravity, if you get the equations wrong while coding, you could have
potential crashes while trying to dock, and since most normal vessels don't have enough mass to attract normally,
why bother to include it?

> Me too. I do remember the logic is quite simple though.

*whew* I was seriously afraid I wasn't going to get my point across. I can't do that well without pictures.


> Agreed. Not to mention the kind of processor you would need to
> compute it in real-time simulation.

I *WILL* get a processor with that capability... someday.... 30 years from now....


> I'll try it with the Death Star addon. That bitch should be
> heavy enough to exibit some kind of attration at least on
> 10000x compression.
>
I hope so..

> Forget that. We've established you only need a normal orbit. I
> don't see a problem then. You managed to set up a
> few planets with moons. This particular one should be similar
> then. Just use moon sized bodies at least. Makes things
> more intuitive
>

I'll tinker with it.

> Hope I can try some of this out over the weekend.
>
me too.

> Cheers,
>
>

[freespace2dotcom]

OK, OK... I just looked at my system again and I just realized that I was measuring the distances of the CENTER of
the planets from the place holder, I thought I was measuring the distances from the surfaces. (!)  As a result, the two
planets were literally almost inside of each other. (kids, don't try that at home!) I suddenly realize where you're
coming from and rest assured I have fixed that by sending them a hell of a lot further away from the placeholder.  I
realized this when I zoomed out a bit further from where I usually did and saw the effect. I don't understand how I
didn't notice that earlier.. I must have been taking stupid pills or something.  But at least they're moving SLOW now!



 I am SOOOO~ stupid... that 100 of those smileys couldn't equal how stupid I am..


 I'm *almost* happy now, but I need to align the planets so that they're exactly on opposite sides of each other, in
other words, their orbit is a circle, have one at 0 degrees of that circle and the other at 180 degrees, (of course,
being able to get rid of that placeholder would be perfect.. hehe)

after that, I *should* be good to go to the next step. Of course I might add a few more planets, and hopefully, they
won't be nearly as hard to add.

[reekchaa]

At least Yer not as Stoopid as the Americans spending millions on an 'ultimate pen.'  
We COULD use an upgrade to VELCRO, however.  

[freespace2dotcom]

That makes me feel a little better, thanks.. but even so, I still am an american, so I guess some stupidity rubs off on
me, I'm afraid.. But what's wrong with velcro?

[Krytom]

I don't think that we should continue on this subject, I can see flameware approaching. Patriotism causes alot of the
flameware on the main orbiter forum. But if it can be kept sensible and mature, then go ahead with the subject. (I am
just trying to stop an argument, nothing personal).

[freespace2dotcom]

yeah, yeah, I understand.. I can see it too.. I'm just being sarcastic again, consider the "stupid" subject dropped.

Edit:  But you still haven't told me what's wrong with velcro!



Post Edited (04-10-04 20:47)

[DocHoliday]

Velcro, I always had a problem with that. Now correct me if I am wrong. The Apollo 1 crew burned up tragically
because of an electrical fire, caused by a loose spark in an oxygen rich environment of the command module. More or
less. Now velcro, when you use it, creates static sparks when tearing off of it, does it not? Or is it limited to the
tearing sound, with no actual static electricity involved??

freespace: Don't worry, I'm a pretty imaginative guy, so I can picture what you say quite well, and I ran some tests
and calculations with the death star. The thing has a huge mass and according to my calculations it should accelerate
an object of DG3 mass (more or less) at a distance of 50km at about 30m/s^2. It does not, ergo, vessels can't have
gravity in orbiter I am SURE we are just too lazy to read the main forum and get the results, but it is much more fun
to come to this sort of conclusions yourself, innit?

Cheers,
Janez

PS: The Pluto addon is here: http://ucsub.colorado.edu/~batemata/orbiter/pluto/ , but it's solved as a planet-moon relationship, so nothing new there. Funny thing. I went to google to look for the addon and it actually found MY post on THIS thread regarding Pluto and Charon. You do have to be careful what you say these days It gets referred to everywhere.



Post Edited (04-13-04 09:43)

[freespace2dotcom]

I really didn't know anything about that. That's very interesting, that story about velcro... it does make sense,
though..

anyways.. since my last post, I've taken care of my problem with the planets spinning around each other for real. But
I'll have to have the place holder until further notice, I added another planet, made the first planet a bit more
feasible, and I'm pretty much done... except...

I looked at that acrobat document about the habitable zones of stars really closely, but I'm afraid it's a tad too brainy
for me.. I would appreciate a little help translating it into layman's terms..

after that's done, then it's on to the textures..

[DocHoliday]

What exactly is bugging you with the habitable zone? It seemed to me, after a quick scan, that for practical (orbiter)
needs, you can simplify the equations quite a lot.

Cheers,

[freespace2dotcom]

I don't know... they just look so.... so... BIG!!!! (and scary!) Albeit I could probably solve them with some time, they've
got a lot of funny looking variables that I've never seen before, so I'm kinda not sure I'd place the correct values into
the equations, thus getting wrong answers. I'm not a rocket scientist, you know...