Programming Question Smaller moon orbit?

[iamwearingpants]

I'm trying to make the surface of the moon 500km above earths :rofl:

The problem is I can't locate the orbital parameters for the moon in it's config file.

Here's what I'm looking at:

  ; === Configuration file for moon Moon(Earth) ===
Name = Moon
Module = Moon
ErrorLimit = 1e-5

; === Physical Parameters ===
Mass = 7.347664e+22
Size = 1.738e6                   ; mean radius
SidRotPeriod = 60591.597       ; = 27.321662 days
SidRotOffset = 0.75049	         ; rotation offset at J2000.0
Obliquity =  0.02692024985275    ; rad(1.5424167)
LAN = 0                          ; ascending node of equator - CHECK!

; === Visualisation Parameters ===
MaxPatchResolution = 8           ; highest sphere patch level

; === Fixed surface observation points ===
BEGIN_OBSERVER
Brighton Beach:Tower: -33.4375 +41.125 120
END_OBSERVER

Am I even look in the right file? (BTW I changed some stuff around )

 

[garyw]

I suspect that moons orbital parameters are kept in moon.dll in the modules folder.

To change the orbit you'd need to rewrite the dll.

 

[T.Neo]

Or remove the link to the .dll in the config file, and put the parameters there instead.

It will not give you as much accuracy, but at least it'll make it possible.

 

[iamwearingpants]

Or remove the link to the .dll in the config file, and put the parameters there instead.

It will not give you as much accuracy, but at least it'll make it possible.

I don't see a link in the config file, hopefully it's not in the dll, because I can't open them. Thanks for the suggestion, I just need to get into that dll and I'm sure it'll work.

 

[garyw]

The line that says MODULE = Moon

That's the link. the cfg file tells Orbiter where to go to find all the various bits of info required for an object. In this case it tells orbiter that there is a module (DLL) called moon which will have the information that orbiter needs.

You can't 'get into' a DLL unless you use a hex editor and if you go down that root you need to reverse-engineer the DLL. Not worth the effort when you can follow T.Neos advice.

 

[Izack]

It will not give you as much accuracy, but at least it'll make it possible.

Who cares about accuracy when the Moon is only 500km away from Earth? :lol:

Also, it's a bit safer to just comment out [add a semicolon (";") to the beginning of the line] the MODULE = Moon line. That way you're not losing any information in case you want to return the Moon to normal later on. If you don't do that, at least save a copy of the vanilla Moon.cfg.

 

[iamwearingpants]

Ok, I was able to change it's orbit by adding the orbit parameters and all that stuff. The problem is I don't know what to put in them to keep it from being earths new core

Right now I have this:

; === Planetary Mean Orbits ===
Epoch = 2000.0                 ; J2000
SemiMajorAxis = 8.500000e+7         ; meters 
Eccentricity = 0.0549
Inclination = 5.145            ; rad
LongAscNode = 0.86530876153          ; rad 
LongPerihelion = 5.8650190805        ; rad
MeanLongitude = 6.20383077256        ; rad

Since I'm a noob as this stuff I can't figure out what I'm doing wrong.

Hopefully it will be easier to recreate the probes holy journey when the moon is closer It'll also be interesting to see the reduced gravity when the moon is in the sky

 

[Izack]

The only advice I can give is to keep fooling around. Adjust the SmA, then open Orbiter and look at where the Moon is, then give or take a few thousand kilometres until you get it where you want it. Normally, the Moon's orbit should be 3.844e8 (distance values in configuration files are always measured in metres.)

 

[iamwearingpants]

Yes! I got it working! All hail the Probe! HAIL IT!