Duna in the deltaV map

[king of nowhere]

why is the surface to orbit deltaV for Duna listed in the map (1450) so high?

you need much less to defeat the gravity, and you only get such a high value on an extremely draggy lander. I mean, I got a 1450 m/s cost to reach orbit. With this craft

as you can see, it's not an optimized duna ascent vehicle. i'd have a hard time making it more draggy than it already is. i used that design because i wanted a lander/rover, that would fit within a 30-parts limit (including launcher), cheap, and that could be reusable for all the small bodies. and of course it sucked on duna, but it worked nicelypassably everywhere else

but that's not a normal duna lander. i hope.

Later i went to duna with a craft that still had poor aerodinamics, but was big enough to not care too much about it

it's still got many flat surfaces and things jutting out from the sides. but it's 280 tons when fully loaded, the square-cube law makes drag much less relevant.

and this thing made it to orbit with 1100 m/s. an optimized lander with good aerodinamics (i've actually never flown one; i like multipurpose ships, and those can't be optimized too much for a specific task) will probably need even less.

shouldn't it be better to update duna's deltaV map with a value around 1200 m/s? a nice compromise between a sucky draggy lander and an optimized one?

or maybe most people actually use sucky draggy landers on duna?

[Dientus]

https://github.com/Kowgan/ksp_cheat_sheets

They acknowledge that more or less are possible and explain where the numbers come from. If its still monitored and you aren't anti-github, you can do a pull request I am sure.

 

[Guest]

I think there’s a couple of those maps going around with different figures on. The main one does list Duna as 1450 but there’s another one which lists it as 1200. 

As a comparison, the 1450 map says 3400 to orbit Kerbin and the other one 3200 so somebody seems to agree with you and has lowered the figures. If you google KSP delta v map it’s the first image that comes up (from Pinterest).

[The Aziz]

Liftoff altitude ASL makes a difference. You'd get better results starting from 6km than from 1km, as, you know, the lower you are, the thicker the atmo is. In fact, at 5km you get a half of "sea level" pressure.

I suppose, dv map was made based on lowest possible altitudes on each body.

[king of nowhere]

i don't know about that. i think it's a "typical optimized" from low altitude. as in, if you make a good launch trajectory, you get that. and it holds for the other planets. on kerbin i really need 3400 m/s to orbit. make it +- 100 for aerodinamics. on eve i actually need 8000 - of course with a very aerodinamic payload, bad aerodinamics would hurt a lot. and 2900 for laythe is also a good approximation, again, with good aerodinamics.

 

what i'm puzzled at, for the other atmospheric planets they are using the value for a craft with good aerodinamics. for duna they are using a typical value for poor aerodinamics. it's like they are assuming that you'll have good aerodinamics when leaving kerbin, laythe, eve, but poor aerodinamics when leaving duna.

and it's actually correct with the stuff i fly, but i doubt i am a common case

[Cavscout74]

It does seem rather high, but then again I've never once worried when I've had extra dV on a mission.