Calculating Delta-V For Landings and Takeoffs

[CalculusWarrior]

The title pretty much says it all, but how would one go about calculating the delta-v required to land or take off from a celestial body? I'm not even interested in exact values, I just want to know how large I should make my landers.

Thanks!

[ThatBum]

[AustralianFries]

-snip-

I was just about to post this.

[CalculusWarrior]

I assume ascent values are roughly the same as landing?

[ThatBum]

If the planet has an atmosphere, you could use aerobraking to help the landing. This is noted in the image. Though, I'd say that logically they would be similar, with the aerobraking doing some of the dV work for you.

[SunJumper]

It's roughly between the escape velocity at the surface, and the escape velocity divided by 1.4, depending on how good your suicide burns are. If the planet has an atmosphere, make that between zero and four times the terminal velocity...