Delta-V to Low Laythe Orbit from the ground?

[going-to-the-MOON]

So, preparing for my first landing on Laythe. Can anyone give me the values of how much Delta-V from Laythe's surface to LLO?

Edited June 15, 2014 by going-to-the-MOON

[mythic_fci]

It depends. If you use a rocket-like lander WITH parachutes, it should only take around 20-40m/s. A powered landing (rockets ONLY) should take 4000-4500m/s. If you use a spaceplane, which many people do because of their good ascent efficiency, it depends; if the lift-to-weight ratio is pretty good (ex. 5 and above:1), you can use none of your fuel - however, if the glide ratio is below about 3:1, you will need about 200m/s for the descent.

Edited June 14, 2014 by FCISuperGuy

[Pecan]

According to the deltaV maps, Laythe launch requires 3,200m/s. http://i.imgur.com/NKZhU57.png

[Epthelyn]

It depends. If you use a rocket-like lander WITH parachutes, it should only take around 20-40m/s. A powered landing (rockets ONLY) should take 4000-4500m/s. If you use a spaceplane, which many people do because of their good ascent efficiency, it depends; if the lift-to-weight ratio is pretty good (ex. 5 and above:1), you can use none of your fuel - however, if the glide ratio is below about 3:1, you will need about 200m/s for the descent.

1) You answered the question the wrong way round

2) You're forgetting that the atmosphere will slow you down; provided you have enough thrust to slow down in the lower atmosphere you can quite easily wait until a couple of km above the surface, at which point the atmosphere will have dropped your speed down to terminal velocity no matter how fast you came in, and then burn. Either way, the ascent and descent dV costs for non-atmospheric bodies are roughly equal if you perform the maneuvers efficiently enough, so there's no chance that Laythe would require 4-4.5km/s to land (given that atmosphere) unless you're doing something really wrong.

As for the actual question, it's about 3-3.5km/s. Probably best to stick with the upper limit given how dV maps are values which expect pretty much perfect landings, ascents and transfers.

[cantab]

There does seem to be a lot more variation in what delta-V maps give for a launch from Laythe than for a launch from Kerbin. I've seen 2800, 3200 (above) and even 3400. Hard to know what the "true" value - which of course should assume a good ascent profile - is.

[thescientist]

On Laythe there is free oxigen, so jet engines works (mostly) fine. That could be a good way to reduce Dv.

Theorically you might even need 0 Dv using the infiniglide bug/cheat/feature.

Edited June 14, 2014 by thescientist

[Red Iron Crown]

The altitude at which you land/launch will affect the dV requirements, too.

[Mesklin]

If you will use pure rocket ascend it will consume 3300-3500 of dV, with jets or RAPIER it will be more cheap. Lander with small lander cabin, 2 FL-T100 tanks (with half oxidizer), one RAPIER, 3 circular intakes and 2 small parachutes can easily land and return to Laythe orbit with spare fuel. Also this craft has possibilities for some landing maneuvers (Laythe has very small quantity of hard surface for landing)

[Mitchz95]

My rocket-powered lander squeaked into orbit with 3100m/s but didn't have enough left to rendezvous with its carrier.

[going-to-the-MOON]

Thanks everybody, my question has been answered.

EDIT: How do I mark this thread as answered?

Edited June 14, 2014 by going-to-the-MOON

[cantab]

Edit your original post and click "Go Advanced".

And hmmm, if 2800 is likely too low then I think I'll have to tweak my own planned ascender a bit.