General Question Minimum PeA for each Planet?

[bcirka]

Hey all. I just flew to Saturn, circularized my orbit, and then got sucked into the atmosphere, which got me thinking...

Is there a list of minimum PeA orbits for each planet? (e.g. I use 200km for Earth, 20km for moon)

Thank you!

 

[jedidia]

Is there a list of minimum PeA orbits for each planet? (e.g. I use 200km for Earth, 20km for moon)

No, because it's not really a fixed thing. It depends on what amount of stability you need from your orbit. In real life, the ISS isn't in a stable orbit, it has to be reboosted every now and then. Yet if you're a temporary visitor and just circling the earth a few hundred times, you'll consider the orbit perfectly stable.

However, for the purposes of numeric expediency, Orbiter does actually have a cut-off limit beyond which it just stops to calculate atmospheric effects. That limit is noted in the cfg file for each planet, although I do not know the parameter name right now. This might be closest to what you want.

Also, on places like the moon that have no atmosphere whatsoever, the minimum stable orbit is essentially the altitude of the highest mountain... :shifty:

 

[Linguofreak]

Also, on places like the moon that have no atmosphere whatsoever, the minimum stable orbit is essentially the altitude of the highest mountain... :shifty:

The OP is rather funny if you make a few weird substitutions:

"I just flew to Mimas, circularized my orbit, and then got (abruptly!) sucked into the lithosphere."

On a more serious note, all that's required is that there is no mountain at a latitude <= your inclination.

 

[Urwumpe]

Also, you can actually dive much deeper into any athmosphere. If you have enough energy, you could even blast past the surface base tower and still be in hyperbolic orbit.

But please, don't try this in the real universe. Your thermal radiation might already be strong enough to obliterate the tower.

 

[bcirka]

Thanks so much, all! Really appreciate the insight.

And I'll check the .cfg for minimums in Orbiter!

 

[martins]

However, for the purposes of numeric expediency, Orbiter does actually have a cut-off limit beyond which it just stops to calculate atmospheric effects. That limit is noted in the cfg file for each planet, although I do not know the parameter name right now. This might be closest to what you want.

The parameter is called AtmAltLimit.

Note that for Earth, this flag is no longer used since the current Earth atmosphere models are more sophisticated and the effective boundary is built directly into the model itself. The altitude limit for both the Jacchia71 and the NRLMSIS-00 models is 2500km.

For details, see Doc\Technotes\earth_atm.pdf.