Dunas size.

[fraczus]

I know from my own experience that Dunas atmosphere starts on 17~18 km and Kerbins at 75 km. That means Duna is 4 times smaller than Kerbin?

[Iskierka]

Duna's atmosphere starts at over 40 km, and Kerbin's ends at ~69.1 km. Besides that, your logic is flawed: it declares that the mun has no size whatsoever.

[Astronomer]

Before anyone starts explaining anything, this is obviously a troll - don`t overfeed it.

[fraczus]

So how we can measure the sizes of planets and moons? Maybe the speed of escape?

PS: Czy aby nie jesteÅ› Polakiem?

[fraczus]

@ Astronomer

No, it's just a mistake. I'm realy curious plantes sizes

[Astronomer]

There are many ways to do it in real life, but in KSP you could put an orbiter at say 200,000km. Than measure the amount of time it takes to orbit each planet on that specific distance (just a guess, might be the same result).

Amd to determine size, you need to know the size of at least one planet (Kerbin). Then it's all just relative.

[Millst0ne MK II]

The Wiki has info on this, I believe.

[maltesh]

The thread Analytically Solving for Gravitationa Parameter and Body Diameter discusses several methods for measuring the radius and mass of celestial bodies in Kerbal Space program using information you can get from the Map Screen.

If you just want to know what the reference radius of Duna is, it's 320 km.

[EndlessWaves]

And of course, as it's a game you can just ask it directly (via a plugin), CelestialBody.Radius looks like a likely candidate.

[AncientAstronaut]

How do you know from experience that Duna's atmo starts at 17 kilometers when it doesn't?

[Vanamonde]

The "experience" Fraczus is talking about is that you have to get about that low before Duna's atmosphere starts to have much affect on your speed. And he's right, it is about 1/4th the altitude at which that happens on Kerbin. The game considers you to have entered Duna's atmo (boots you down to warp 1) at around 47,000m, though, so I think that's the official upper limit.

[fraczus]

Thanks for everyone

@AncientAstronaut

It was just my mistake, because I was on Duna and when I was on closed orbit at 17km and the ship started to slow down so I thought It was upper line of atmosphere