Delta V from Mun orbit straight into Kerbin

[mellojoe]

I'm attempting to make an emergency pod. Where can I find out how much Delta-V I would need these to have in order to go basically straight from a Mun orbit back to Kerbin. I don't need to orbit Kerbin, so the charts I found don't seem to apply. They all show Delta-V from orbit to orbit. I just need to get to where I can hit atmosphere of Kerbin and let natural decay take over at that.

I can guesstimate, but since these are for "emergency" purposes, I want to make sure I don't under-guess and strand my team.

Edited July 28, 2015 by mellojoe

[Mastikator]

Takes about ~250m/s dV to go from low mun orbit to suborbital kerbin in my experience. I'd bring 300m/s dV just to be sure.

[Empiro]

The delta-V charts definitely do apply, but you need to know when the atmosphere can help you. If you're using something like this http://i.imgur.com/UUU8yCk.png, you can see where you can aerobrake. In this particular case, you can see that it takes about 300 to go from low Munar orbit to a Kerbin-Mun transfer orbit, at which point you can aerobrake down to Kerbin.

[mellojoe]

Thanks, guys.

[mrclucks]

Can't give you numbers, but a great way to test it out is to send a rocket to the mun and circulize at the same altitude as your station will be, then just use a maneuver node to figure out how much dv will be needed.

I believe any periapsis should start you decaying your orbit except for maybe one just below 70km that last for a second or two. Also depends how hardy your craft is and if it has airbrakes or if it is not very aerodynamic. I usually build my return vehicles pretty hardy with only a heat shield to guard from reentry heat and aim for a periapsis of 30km, but you could go for one at 50-60 if you're sending a pancake in and not have to make a billion orbits to return.

[Nich]

Bare command pods do just fine hitting 35 km. My escape vehicles are a docking port junior, a command pod, decoupler, the second smallest 1.25m tank with 20 units of LF and matching OX, and a terrior

[tadswana]

30km periapsis on return? Wow, you don't have any thermal problems with the new patch? I like the aggressiveness.

Been trying to work out the optimal periapsis for Duna, anyone have any experience here? I hit way to aggressive last time and burnt up...

[MaverickSawyer]

30km periapsis on return? Wow, you don't have any thermal problems with the new patch? I like the aggressiveness.

Been trying to work out the optimal periapsis for Duna, anyone have any experience here? I hit way to aggressive last time and burnt up...

If you're doing a lifting reentry,, I'd aim for an inverted reentry at 37 km or a little higher. Lower if it's a purely ballistic reentry.