General Question Can a Moon have a Moon

[Iacomus Maximus]

Does Orbiter support moons with moons?

 

[Yurik]

Yes

 

[Donamy]

That's essentially what happens, when you go into lunar orbit. You become a moon, around the moon..

 

[Dantassii]

You haven't looked at any of my IMS ships lately have you? At least 2 people have commented "That's not a spacestation, that's a Moon!".



Dantassii
HUMONGOUS IMS shipbuilder

 

[Spacethingy]

Is there a limit to how moon-ception-ish a system can be in Orbiter? (And, out of interest, IRL too?)

"Yo dawg, I heard you like orbiting moons..." etc. etc. etc.

 

[Izack]

You can at least have moons of moons of moons.

 

[Kyle]

A moon of a moon of a moon?

 

[Iacomus Maximus]

I appreciate all your responses, however, as it is here at work as well - I should have been more specific (we tend to be mercilessly specific).
Is it possible to script a moon as having a moon.
I've taken an existing moon (such as Hyperion and made a copy named luna.cfg for example)
I then edited the orbital mechanics entries (as best I could) and attempted to re-script it and insert it into the sol.cfg file.
I used Hyperion because it doesn't have an associated module.

For example - adding this last line in sol.cfg: (which I've tried and doesn't work)
Star1 = Sun
Planet1 = Mercury
Planet2 = Venus
Planet3 = Earth
Earth:Moon1 = Moon
Moon:Moon1 = Luna

---------- Post added at 01:08 PM ---------- Previous post was at 01:05 PM ----------

You can at least have moons of moons of moons.

Orbiter - moons of moons of moons - YouTube

How did you accomplish this?

 

[Ripley]

What you did isn't enough.
I guess you have to create as well a "Luna.cfg" file and edit its orbital parameters, in order to put it around the Moon (I've never tried these things myself).

 

[Iacomus Maximus]

I've edited my previous entry to be more specific of what I actually did.

 

[jedidia]

Star1 = Sun
Planet1 = Mercury
Planet2 = Venus
Planet3 = Earth
Earth:Moon1 = Moon
Moon:Moon1 = Luna

This works, but as Ripley said, you also need to create a config file for the new Body, named Luna.

Is there a limit to how moon-ception-ish a system can be in Orbiter? (And, out of interest, IRL too?)

Unknown. The architecture certainly wasn't designed for it, the possibility is just the result of an open parent-child relation between bodies. Technically, it shouldn't pose any problems, but it's always possible that such abuses lead to weird results because the use case was never tested.

IRL, The only thing we know is that we have never seen it occurring, but that the chances of it occuring are extremely slim. The reason for this is that by current accretion models, there's just no configuration in which this can appear. The closest phenomenon that might reasonably have such a configuration is a far binary, where a planet of the orbiting star has a moon, but we don't know of any definite occurences.

Otherwise, the accretion moddels just leave no room for a gas cloud forming around a body while it is in too steep a gravity gradient from another body. It would be imaginable that a large, wide-outlying moon of a gas-giant might be able to capture itself a satelite. But a) we do not know of any large wide-outlying moons of gas giants, b) the models don't think this would be a very likely phenomenon in the first place, and c) the circumstances in which such a body manages to snag a meteorite without the larger body grabbing it first would have to be considered extraordinary indeed.

 

[Iacomus Maximus]

This works, but as Ripley said, you also need to create a config file for the new Body, named Luna.

I have again edited a previous post to better describe what I have attempted so far:
I've taken an existing moon (such as Hyperion and made a copy named luna.cfg for example)
I then edited the orbital mechanics entries (as best I could) and attempted to re-script it and insert it into the sol.cfg file.
I used Hyperion because it doesn't have an associated module.

For example - adding this last line in sol.cfg: (which I've tried and doesn't work)
Star1 = Sun
Planet1 = Mercury
Planet2 = Venus
Planet3 = Earth
Earth:Moon1 = Moon
Moon:Moon1 = Luna

If someone has made this work would you please share the .cfg file for the star (sol in my example) and the moon (luna in my example)

The only thing we know is that we have never seen it occurring, but that the chances of it occuring are extremely slim. The reason for this is that by current accretion models, there's just no configuration in which this can appear. The closest phenomenon that might reasonably have such a configuration is a far binary, where a planet of the orbiting star has a moon, but we don't know of any definite occurences.

"You may need to add capturing an asteroid and placing it in a stable orbit around the moon" to your list in the upcoming years

 

[n122vu]

I'm sorry, I couldn't help myself...

 

[kamaz]

"You may need to add capturing an asteroid and placing it in a stable orbit around the moon" to your list in the upcoming years

Given that asteroids are known to have moons...

 

[jedidia]

For example - adding this last line in sol.cfg: (which I've tried and doesn't work)
Star1 = Sun
Planet1 = Mercury
Planet2 = Venus
Planet3 = Earth
Earth:Moon1 = Moon
Moon:Moon1 = Luna

I never did it myself, but we had a thread about it some years ago about binary systems where somebody posted a working configuration, but I can't find it anymore. So I can't tell you exactly what's wrong here, but trying to see through the text file to the underlying program logic (which is no more than a moderately informed guess), I would try to define it like this and see if that works:

Earth:Moon1:Moon1 = Luna

"You may need to add capturing an asteroid and placing it in a stable orbit around the moon" to your list in the upcoming years

Indeed. Though I would expect that if we start capturing asteroids, we would deposit them in a high earth orbit, seeing that our means to reach the moon are a bit limited at the time...

 

[Izack]

Yes, that will work. For the video I used:

...
Earth:Moon1 = Moon
Earth:Moon1:Moon1 = Enceladus
Earth:Moon1:Moon1:Moon1 = Phobos
...

With some semi-major axes divided by 10 or 100.

There are some issues, though. For example, Orbiter's camera cannot focus on a moon of a moon.

 

[kamaz]

Indeed. Though I would expect that if we start capturing asteroids, we would deposit them in a high earth orbit, seeing that our means to reach the moon are a bit limited at the time...

No, for two reasons:

1. We can reach the moon orbit -- it is landing which is the problem. We just don't do this because there is nothing there... Although there is a proposal to build the next ISS at L2.

2. If something goes wrong, and the asteroid deorbits, hitting the moon is preferred to hitting the Earth...

 

[jedidia]

1. We can reach the moon orbit -- it is landing which is the problem. We just don't do this because there is nothing there... Although there is a proposal to build the next ISS at L2.

What, at the earth-moon lagrange point? what possible reasoning could there be behind building a station there, when enough people already complain that we don't really need one in LEO?

 

[Iacomus Maximus]

There is an actual initiative to capture an asteroid and put it in a stable orbit around the moon to somehow practice going to Mars.

I wasn't aware of the L2 ISS proposal; however, I did find this:

The Exploration Gateway Platform is a design proposed by Boeing in December 2011 to drastically reduce the cost of Moon, Near Earth Asteroids (NEAs), or Mars missions by using components already designed to construct a refueling depot and servicing station located at one of the Earth–Moon Lagrange points, L1 or L2. The system claims its cost savings based on an ability to be reused for multiple missions such as a launch platform for deep space exploration, robotic relay station for moon rovers, telescope servicing and a deep space practice platform located outside the Earth's protective radiation belts.

The platform would be constructed at International Space Station (ISS) for testing before being relocated to L1 or L2 via electric or chemical propulsion rockets.

The Platform would consist of parts left over from the ISS program. Parts currently under consideration are Node 4 to form the main connection point, parts from the Space Shuttle's Orbital Maneuvering System (OMS) and Orbiter External Airlock would be combined to form a utility module for maneuvering, orientation and Extra-vehicular activity (EVA), a smaller version of the Canadian Arm to help with logistic and station-keeping, one of the remaining MPLM and/or possible inclusion of a 'Zvezda 2' or a Bigelow Inflatable station for life support systems, crew accommodations, storage, and laboratory space. Most components would be lifted into orbit using currently available EELV or commercial launchers. A reusable lander would be positioned at the platform for Moon landings and refueled using NASA's new SLS heavy lift vehicle.