Delta V to take off planets/moons and return to Kerbin.

[funkey100]

I've seen Delta V maps that show how much you need to orbit Kerbin, get out of it, encounter another body, orbit it and land. Yet I haven't seen too much on what you need to launch from another body and get back to Kerbin. Anyone have a map or list or chart? I mainly need this for my advanced Mun rocket but it would be nice if I could get the other planets and moons too.

[Supernovy]

Except on atmospheric bodies, the delta-v required to get there is the same as the delta-v required to get back.

Tracing a path backwards on a delta-v map should give the return delta-v.

[funkey100]

So it would require 1.71 k/s from the Mun or 5.04 k/s from Eeloo to get back to a Kerbin orbit according to this map? What about bodies with atmospheres?

[tomf]

Most of the bodies with atmospheres will have a rough guide to the DV required to get into orbit written on their wiki pages. The amount you require is going to depend upon design and piloting a fair bit but if you allow 10% more than those quoted figures you should be able to make it.

[Mr Shifty]

So it would require 1.71 k/s from the Mun or 5.04 k/s from Eeloo to get back to a Kerbin orbit according to this map? What about bodies with atmospheres?

I'm never sure how those maps work. You can get from low Eeloo orbit to Kerbin for around 1000 m/s. Kerbin has an atmosphere, so you can use it for aerobraking; no need for an injection burn. I use this tool for interplanetary delta-V's:

http://alexmoon.github.io/ksp/

[Skorpychan]

I'm never sure how those maps work. You can get from low Eeloo orbit to Kerbin for around 1000 m/s. Kerbin has an atmosphere, so you can use it for aerobraking; no need for an injection burn. I use this tool for interplanetary delta-V's:

http://alexmoon.github.io/ksp/

You read it like a subway map, with the numbers being dV between the nodes. Makes perfect sense to me.

[Mr Shifty]

You read it like a subway map, with the numbers being dV between the nodes. Makes perfect sense to me.

What I mean is that the delta-V predictions are almost never close to what I end up using. Case-in-point, that one says 3250 m/s to get from low Eeloo orbit to Kerbin intercept, which is ludicrous. A Hohmann transfer from a 10km Eeloo orbit to Kerbin intercept takes something like 1360 m/s, plus a small bit for an inclination change, and because Eeloo's orbit is eccentric, you can do it for about 1000 m/s when Eeloo is close. Likewise, it says about 4100 m/s for an LKO to LEO transfer, but you can easily do it for under 3500 m/s.

[tomf]

The chart does have markers for transistions for which you can use aerobraking, for which you can normally ignore ~90% if that cost. They ignore the eccentricity of the orbit as well, so if you are able to catch the eccentric eeloo at its AP you will probably end up with significant savings over the prediction.

[capi3101]

My understanding is that the delta-V charts represent optimal averages for planning purposes only. They aren't hard and fast numbers for every case, so sometimes you can get away with having less delta-V available (and sometimes you need LOTS more). Think of it this way: if you wind up using less delta-V for a transfer than the map says you need, you've got that much extra available to you in the event of a screw-up later in the mission. Margin for error and all that jazz.