Advanced Question Tidal Forces etc.

[talavar]

I was just wondering if the planets in Orbiter actually have an effect on the other planets, or only on your craft. ive downloaded a few nonfiction NEO's and found that one of them (Rather large) pass between the earth and the moon in 2344. Ive checked the trajectory quite a few times from many different sources and always get the same information. However, if non-spacecraft objects in orbiter do not have an effect on each other its quite possible that what im viewing in that time period is wrong and its possible that earth could sling it into an orbit which would cause it to hit earth rather than just pass us by. granted i know nothing is ever totally precise in orbiter, and over a course of a few hundred years, this information could actually need to be corrected, but as it stands now its looking close!

 

[martins]

Orbiter's planetary epemerides are computed by a (semi-analytic) perturbation series solution. The series coefficients are determined by high-fidelity numerical models (e.g. VSOP87). This means that adding additional gravitation sources will not affect the planet orbits (and will consequently lead to inconsistencies between planet and spacecraft trajectories, resulting in pseudo-forces).

It is however possible to build a "dynamic" solar system by modifying the planet configuration files. You can specify the ephemeris calculation method, so you could switch from external (DLL) calculations to dynamic updates. The accuracy of the orbit calculations will depend on step sizes and may deteriorate over longer times. Also, you will need to specify the osculating orbital elements at a reference time. Orbiter will use 2-body calculations for advancing the planet states from the reference time to the simulation start time, which will be inaccurate for large time differences.

 

[the dude]

Have a look at my vid on youtube Orbiter Planets and rocks I downloaded the asteroid pack 1.00 and edited the config file changeing hasorbitalelements from true to false this allows planets to change the asteroid orbitsit also works for the apothis asteroid in the art addon.

 

[CaptnDave]

Nicely done! :speakcool: I wonder how much prossesor power it would pull to have everything always affecting everything... Someone should write a .dll for switching between set orbits for during high time compression and dynamic orbits for more reasonable speeds. It would be interesting to try, to say the least.

 

[2552]

Orbiter's planetary epemerides are computed by a (semi-analytic) perturbation series solution. The series coefficients are determined by high-fidelity numerical models (e.g. VSOP87). This means that adding additional gravitation sources will not affect the planet orbits (and will consequently lead to inconsistencies between planet and spacecraft trajectories, resulting in pseudo-forces).

It is however possible to build a "dynamic" solar system by modifying the planet configuration files. You can specify the ephemeris calculation method, so you could switch from external (DLL) calculations to dynamic updates. The accuracy of the orbit calculations will depend on step sizes and may deteriorate over longer times. Also, you will need to specify the osculating orbital elements at a reference time. Orbiter will use 2-body calculations for advancing the planet states from the reference time to the simulation start time, which will be inaccurate for large time differences.

As a kind-of related question, say you have a DG orbiting Triton. Does Orbiter take into account the gravitational influence of, say, Phobos, on your orbit at that distance? Is there a threshold below which a body's gravity is not factored in?

 

[martins]

There is a threshold. Go to the information page (Ctrl-I) of the vessel and scroll down. At the bottom should be a list of gravity sources currently taken into account.