Setting Multiple Objects in stable orbit near each others

[Goudaba]

Hello,

I am currently constructing a space station around Kerbin and had an idea to light it entirely without hampering my CPU performances too much, however, I do not know if it is even possible.

The idea I had (and failed to properly implement) was to have some basic probes attached to one of the station component.

Probes would be made of:

- 1 basic probe body

- 2 solar panel

- 1 battery

- 1 xenon tank

- 1 xenon propulsion device

- 1 large lamp

From there, I would attach the section to the main station and then lunch the "light probes" separately to light the station from a short distance.

--> However, after several attempts to stabilize the probes, they would always drift and would be out of reach of the main station after about 2 full kerbin revolutions.

I would like to know if it would be possible to completely stabilize, even if it would be REALLY hard, the orbit of those probes around the main station or if the slight difference in distance would modify the orbit just enough to make this impossible?

Thanks in advance for the answers.

Edited November 12, 2013 by Goudaba
Question answered

[How2FoldSoup]

I feel I might be misunderstanding what you are asking so correct me if I'm wrong, but couldn't you just dock the probes onto your main station component to stop them from drifting away? The reason the probes drift is due to how orbital mechanics work at their lowest level.

If your goal is to light your station without having the lighting probes docked you would have to have an autopilot hold their position relative to the station...which I'm not sure is possible in kerbal.

I was just reading about a mod called TTNeverUnload and if it lets(an aspect of the mod that I am unsure of) simultaneous control of multiple craft then you could attempt to have mechjeb running on the probes and keep them in place. I honestly don't know exactly how you would do it but that may be your best bet.

I need to ask though why create separate craft to light your station? Instead of having a 7 part lighting probe wouldn't it just be more cpu efficient to just put lights on the station itself? Most of the lag created by monstrous creations is the amount of physics calculations needed to be done on every part in the area. More parts generally means more lag. I think you may be over complicating a simple solution.

Once again though I may be misunderstanding..

Hope I helped!

Soup

[Kasuha]

There is only one theoretically possible way to set up two objects to orbit a body so they stay in constant distance and relative position from each other (in KSP physics). They must be on exactly the same orbit, one a bit ahead of the other. But there's no way you could do anything like that, over long time spans they will deviate due to minute differences in speed and position. So the only reliable way to light your station is by something that's part of it. You can for instance build some light poles from modular girder segments with docking port at one end and lights at the other end and dock them with your station.

Leaving two things in a very close orbit and position is dangerous. When you use time warp, the two objects may by chance overlap each other and when you switch to them and decrease the time warp to x1 they will explode. Don't do that.

Edited November 11, 2013 by Kasuha

[Kerbart]

In KSP? Not even theoretically possible. IF, and this is a big if, you mention to set up orbits in a perfect way so that your lighting probes will indeed light the space station, you will have the challenge that spin is not a variable when on rails. And if your probes are not spinning.... They'll continue to point in one direction, so while your probe might be pointing *toward* your station at one point in orbit, it will seem to be pointing *the other way* half an orbit later.

Then, they need to be in *exactly* the same orbit, just a few seconds ahead or behind. So you'll have light on a single axis, coming from two opposite directions. Any photographer can tell you it won't look too good. From the side of that axis? Well now you're on a higher (or lower) altitude so your probe will drift away.

And all that is based on the assumption that you have perfectly matching orbits. Try getting a perfectly circular orbit in the first place (ignore the AP/PE markers racing around like crazy) and you'll notice that it's pretty impressive to get them lined up within 500m of each other. Which, when it involves another spacecraft, still represents a variance of ±250m, way more than you want it to be.

No, your best bet will be struts and beams and lattices.

[KerbMav]

The Scott made a video about editing the orbit parameters in the savefile.

But I am not sure you would really safe resources, because for the lights to do something they would have to be in physics range anyway?

[Monkeh]

The Scott...

Is this the new way to refer to Mr. Manley? Like thespians calling Macbeth 'The Scottish Play'? Will a simple uttering of his name cause us to have bad luck?

Now I fear for my life!

[Kerbart]

The Scott made a video about editing the orbit parameters in the savefile

But even that wouldn't deal with the problem of the lights pointing in the wrong direction (due to not rotating while in orbit) and the problem that, when docking, you're shifting the station around ever so slightly so eventually it'll wander off (unless you're willing to edit the orbit parameters of the station over and over again)

[Kasuha]

But even that wouldn't deal with the problem of the lights pointing in the wrong direction (due to not rotating while in orbit) and the problem that, when docking, you're shifting the station around ever so slightly so eventually it'll wander off (unless you're willing to edit the orbit parameters of the station over and over again)

You can put multiple lights to probe and shine in all directions.

Edited save file would work only until you switch to the station in physics mode (x1 time warp). Once you do it the orbit will get changed very slightly but enough to divert over long course.

[DrMonte]

As someone said you should align speed, not the orbit. Anyway corrections will be required time to time regardless the perfect your orbit is.

[KerbMav]

Is this the new way to refer to Mr. Manley? Like thespians calling Macbeth 'The Scottish Play'? Will a simple uttering of his name cause us to have bad luck?

Now I fear for my life!

Actually, as Mr Manley's given name is Scott, it was meant to create a sense of reverance.

It was no allusion to his heritage, although he does quite a funny Sir Connery impression!

[allmhuran]

Actually you could also deal with the "lights along one axis" problem by having the lights in the same orbit as Kerbin one second and two seconds behind, and then incline the orbit VERY slightly in opposite directions. Most of the time you will then get light coming in at complimentary angles, only at the ascending and descending nodes would you have all the light along one axis. If you use four probes (1s behind, 2s behind, 1s ahead, 2s ahead) on very slightly different inclinations then you could light the station quite nicely.

Having said that, it's just so much easier to put the lights out on your solar panel structures.

[Goudaba]

Thank you all for the answers,

finally, I think I'll need to use a "thug" and de-orbit some modules and rethink them to include lights properly since I want the station to be a no-mods/no edit build.

The main reason I wanted to try to include light probes in a static orbit around the station was to to be able to light the entire station with the same number of lights, even as I add modules to it.

I could always use the light probe design for screenshot purpose only as I could detach the probes, place them temporary, take a good screenshot and then dock them back to the main station.