Three Parts to Laythe

[aubranium]

After watching StratzenBlitz75 and Hazard-ish go to Gilly and back with three parts, I wondered if we could make it to Jool with a similar design. Can you make it to Laythe and land Kerbals safely, using only three total parts and no orbital refueling? 

Note: according to the delta-v map, this requires at least 6420m/s (not including inclination requirements), which is more than the maximum available in the three part design.

Big shout outs to @Stratzenblitz75 and @hazard-ish for inspiring this thread!

Edited September 21, 2019 by aubranium

[Aetharan]

The Retro-Solar Rescue thread pretty well demonstrated that "having enough delta-v to brute-force your way to the destination" is not the only way.  I'm sure that somebody better than I am at gravity assists could pull it off.

[aubranium]

I made it to Laythe with about 250m/s remaining dV. Believe it or not, on the very first try. Good luck Kerbonauts!

 

[tseitsei89]

5 hours ago, Aetharan said:

The Retro-Solar Rescue thread pretty well demonstrated that "having enough delta-v to brute-force your way to the destination" is not the only way.  I'm sure that somebody better than I am at gravity assists could pull it off.

This. If you have enough to escape Kerbin SOI you need really little dv. You just need A LOT of time, but without life support time is "free"

[aubranium]

10 hours ago, tseitsei89 said:

This. If you have enough to escape Kerbin SOI you need really little dv. You just need A LOT of time, but without life support time is "free"

Agreed. My difficulty in the above attempt was waiting until Jool periapsis before executing the transfer burn. KSP doesn't have any stock tools for this kind of planning, so I'm intrigued by the prospect of building tools to solve the problem. In theory, one could compute a similar set of paths to the Interstellar Transport Network, using the Kerbol system instead. Unfortunately, KSP doesn't support the multi-body physics required to achieve this.

It took a while to figure out the timing. I used Hohmann transfer to approximate the transfer orbit time between Kerbin and Jool and waited until Jool was that far from its periapsis. I failed to account for Kerbin's alignment so I had to wait another 300days for favorable Kerbin alignment. Still, Jool moves slowly enough that it didn't matter much. I was amazed I was able to execute the transfer on the first try. This leads me to believe it may be possible to do a 3 part landing on a Jool moon *and* return to Kerbin.

[Pds314]

Getting to Laythe wouldn't be impossible, But getting back might be.