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captainb

dV budget for Jool system operations?

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I'm planing a manned Jool mission for my career save.  The focus will be on extracting as much sweet, sweet science as possible from the Jool system before returning home to Kerbin.  I'm going to use a NERV powered main mothership with 3 daughter landers to cover all the moons. (The Tylo lander will be an unmanned one-way trip!)

Since this will be my first visit to Jool, I'm not sure what to expect for dV requirements after I capture into the Jool SOI.  For a conservative estimate, I could simply add up all the numbers from the KSP delta-V map to get intercepts with each moon including the plane change amounts.  This assumes (1) that the parent body will be Jool every time  (2) no gravity assists from the other moons and (3) no daughter vehicles. 

With this in mind, do people have a ballpark number for the delta-v requirements to encounter all Joolian moons?  I'm looking for rough estimates as a gut-check for my planning purposes, preferably from those who have done similar missions.

I should also mention that I'm not planning to do any resource extraction, but I might need to if the dV requirements are too high.

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First off, you should not need to do any mining whatsoever. The Jool system is 100% conquerable without mining. Now, to the estimates. Looking at some rough Hohmann transfer window numbers, I would ballpark 5,200 m/s (assuming you start and end at Vall), not including delta-V required to get to Jool and get back. Breaking that down, that's Vall->Laythe, 900 m/s , Laythe->Tylo, 1500 m/s , Tylo->Bop, 1300 m/s , Bop->Pol, 600 m/s , Pol->Vall, 900 m/s.

As an aside, for getting to Jool, you should consider figuring out gravity assists. A Laythe or Tylo gravity assist can mean a free capture into the Jool system, which can save a couple thousand m/s. Using gravity assists to get there can save another thousand or so, but is both difficult and mind-numbingly tedious, so I don't recommend it if you're willing to just throw some more delta-V at the problem. For getting back, it's advisable to try and take advantage of the Oberth effect and eject straight from low orbit of some moon, to the tune of more delta-V savings.

Hope these things helped. The Jool system is one tough cookie to take on all at once.

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Hmmm.  That's pretty close to my worst case scenario estimate of 5500 m/s.  I will have to give this some more thought.   Is aerobraking at Jool/Laythe worthwhile or not really?

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4 hours ago, captainb said:

Hmmm.  That's pretty close to my worst case scenario estimate of 5500 m/s.  I will have to give this some more thought.   Is aerobraking at Jool/Laythe worthwhile or not really?

Aerobraking at Jool is impractical to the point of uselessness. The same can be said of Laythe, unless you've already captured in the Jool system. Gravity assists are the best bet for cheap captures.

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You can use Flyby finder to find slingshot opportunities both in the way or at joolian system. 

Alternatively you may try to ask nicely and hope someone can help you. (don't look at me,  using trial and error myself) 

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