How a build a 22,000 m/s dV spaceship?

[Streetwind]

1 hour ago, Laie said:

Sorry, cannot resist the urge to nitpick...

It is totally possible to be too miserly with the engines. When leaving Kerbin, I'd recommend a TWR of no less than 0.15 (preferably 0.2) -- below that, the losses from a long-duration burn will be greater than the straightforward dV loss from adding more engine mass.

That is why I disclaimed with "... that cannot also be mitigated through skillful flying" Periapsis kicking is a perfectly servicable, if rather tedious, way to leave Kerbin without maneuvering losses.

 

34 minutes ago, luizopiloto said:

22000m/s Δv... does it have to be manned? if not... IONs...

He writes further up in this thread that he doesn't have them unlocked yet.

[Draalo]

20k dV Ionvessel for 2 crew

contains an OCTO2 too, read the post from @Streetwind (thx btw.) while constructing. removing the 2nd lander can raise total dV over 22k (!)

Skipper + Poodlecombo - payload could be extended even more with bigger Engines

Atmo TWR is 1.46 for liftoff

added 4x small radiator - dunno if that is much enough, i have no experience near Sun Kerbol

 

But note the loooooong burntimes and loooooow TWR. Paneels should privide enough EC vor continuous firing near Sun

Hint: you can activate physical timewarp (x2, x3, x4) using ALT + "." - german keyboard while accelerating - but the mission will still be a pain.

But hey - every Kerbal deserves to be rescued

(Disclaimer: its just a study - i did not do any experiments with this vessel myself. Some tech may not be availiable and must be substituted.)

 

More detailed view of the upper stage:

moar

Edited February 8, 2018 by Draalo

[Laie]

@Streetwind: periapsis-kicking is only good for the first 1km/s, from then on you have to pull through in one go. When going to Jool, that's another 1100m/s or so you have to provide in a single burn. Believe me, I didn't pull that 0.15g figure out of my nose, nor any other orifice: at that acceleration, said burn lasts over 12 minutes, and  no matter how smart you set it up, you'll spend an extra 100m/s compared to doing it on a still leisurely 0.3g.

Just check your dV meter before and after the burn to get at the actual dV expenditure.

Edited February 8, 2018 by Laie

[Streetwind]

Then we will have to agree to disagree, @Laie, since apparently our ingame experiences differ. I'm a contributor and great fan of Near Future Propulsion, and my playthroughs are often filled to the brim with low-TWR ion spacecraft. I've gotten pretty good at getting where I want to go in the dV budget that it's supposed to take. Obviously there are some small losses compared to instantaneous impulse maneuvers - nearly any engine will have those. But I can't remember missing a node budget by a 10% margin.

Not saying your results are wrong - just saying my mileage varies.

Edited February 8, 2018 by Streetwind