Vall Landing delta V

[Captain Sierra]

Okay, I give. Even a veteran such as myself doesn't know everything. How much dV does it take to get off of Vall? Assuming I start from a parking orbit somewhere between 25 and 45km, how much dV does it take to get down to the Vall surface and back up to that same orbit (or higher/lower, for rendezvous)?

And in case anyone is curious, I'm headed that way with a two stage Tylo lander (technically 5 stage since the upper has 1 set of drop tanks and the lower stage has 2 sets of drop tanks). I wanna know if the remaining upper stage core will have enough dV to get off of Vall once I refuel it.

[Guest]

The delta-V map I like to use says 1180, but I generally overbuild a bit so I have extra for unplanned events and for rendezvous (oftentimes the tug doesn't have RCS). 1.5km/s both ways worked pretty well for me. Last time I went to Vall I used a lander built for Moho, ran out of fuel about 20m up (worked out well, I guess), but I had plenty in the return stage.

Vall is kind of tricky to land on, it has a very deceptive gravity. Surprisingly I find Moho to be easier to land on (not necessarily travel to, though).

[Tank Buddy]

According to the DV maps, it looks like 1176 m/s to land, and 790 m/s to take off, or vice versa. The maps provide unclear instructions on what is what, but I'd plan for 1300-1400 m/s.

[lajoswinkler]

This app says 1176 m/s, and that you can do better.

[hermes47]

From a 100 km orbit, the ∆v required, assuming a perfect suicide burn to 0 m ASL, is 929.79 m/s. SO something around 1 km/s is probably a 'safe' bet.

[Captain Sierra]

The delta-V map I like to use says 1180, but I generally overbuild a bit so I have extra for unplanned events and for rendezvous (oftentimes the tug doesn't have RCS). 1.5km/s both ways worked pretty well for me. Last time I went to Vall I used a lander built for Moho, ran out of fuel about 20m up (worked out well, I guess), but I had plenty in the return stage.

Vall is kind of tricky to land on, it has a very deceptive gravity. Surprisingly I find Moho to be easier to land on (not necessarily travel to, though).

So 1500 dv does the trick. In that case my current upper stage is a bit shy on fuel.

[tanuki_chau]

I usually try to compare planets so , Tylo is equivalent to Kerbin sans atmosphere. Val is equivalent to Duna sans atmosphere.

[tavert]

Depends on your TWR: http://forum.kerbalspaceprogram.com/threads/39812-Landing-and-Takeoff-Delta-V-vs-TWR-and-specific-impulse. 1100+ is very conservative. Around 900 plus the cost of transferring down to a low circular orbit just over the terrain should do it if flown well.

[SSSPutnik]

Call gravity does kick in a bit deceptively as you descend. If you can make Tylo orbit, I would have thought it would be OK? What's your dV?