Delta/v for the way back

[Cairol]

Is there a source similar to the Delta/v map here to give the needed delta/v for the way back from a body to kerbin?

Or a rule of thumb?

Because when designing my rockets, I still struggle on how much delta/v to plan for a safe return and often get stranded somewhere in between.

I guess it's not the same amount than you need to get to another planet. It's probably less for all target planets with less g than Kerbin. But how much less exactly?

And how is it when returning from higher g planets?

Edited August 27, 2015 by Cairol

[Streetwind]

Rule of the thumb is to count backwards from the body on the dV map.

Sure, your maneuvers will never be exact mirrors of one another, but the basic gist is that it takes as much dV to go one way as it takes to come back the other. For example, if it takes you 1,000 m/s to go to the Mun (a 860 m/s transfer plus a 140 m/s capture and circularize), then going back to the same low Kerbin orbit you started from, will also cost you 1,000 m/s (this time a 250 m/s transfer and a 750 m/s circularize).

The nice thing with Kerbin is the atmosphere, so you can always aerobrake/direct EDL and skimp on the orbit insertion and circularization dV.

[capi3101]

Most of the delta-V maps you'll come across (like these) will have arrows on them indicating "aerobraking possible". Where those exist, you can essentially discount any delta-V requirement for the return trip entirely. For example, a Mun orbit takes 1,170 delta-V - 860 to get the intercept from LKO, then 310 to get from the intercept to LMO. The return trip, however, only requires the 310 to escape the Mun's SOI; 860 for the return flight isn't necessary because you can aerobrake back down to LKO (and beyond).

For planning purposes, until you get the hang of it, you might put a little margin in for where aerobraking maneuvers are indicated. Even then, you don't need much - 50 m/s tops. A small supply of RCS fuel and a few blocks might cover it as well. When I was first starting out I'd plan for the various phases of my missions with 125% of the indicated delta-V requirement (to have a little safety margin in case of screw up) and in almost every case it worked well (the exception being Moho, because there are special guidelines to follow when you're shooting for Moho's orbit...).

[SchweinAero]

Here are some examples, based on this chart:

Kerbin -> Eve 4540 m/s (3500 to low orbit + 1040 to transfer + aerocapture/braking to surface)

Eve -> Kerbin 8500 m/s (7000 to low orbit + 1500 to transfer + aerocapture/braking to surface)

Kerbin -> Duna 4580 m/s (3500 to low orbit + 1080 to transfer + aerocapture/braking to surface)

Duna -> Kerbin 2240 m/s (1500 to low orbit + 740 to transfer + aerocapture/braking to surface)

Kerbin -> Dres 5060 m/s (3500 to low orbit + 1560 to transfer + 1140 to capture + 150 to low orbit + 430 to surface)

Dres -> Kerbin 1720 m/s (430 to low orbit + 1290 to transfer + aerocapture/braking to surface)

[Cairol]

Thank you all. This was helpful!