Kerbin orbit to Jool orbit for 855 m/s

[camacju]

I've been playing around with some possible methods to use gravity assists off the Mun to get to other planets. One gravity assist by itself isn't enough to make a big difference. However, you can eject into a resonance with Kerbin and grab additional Mun assists to pick up energy as demonstrated by Vector. He took a craft from LKO to Eve for 873 m/s.

I have a post where I got from LKO to Eve for 841 m/s. In this run, I use 3 m/s in course corrections between Eve and Jool. So theoretically 844 m/s Kerbin to Jool is possible. I'm leaving this opportunity open for someone who is a better pilot than I am.

The route: Kerbin-Mun-Mun-Kerbin-Mun-Kerbin-Mun-Eve-Kerbin-Kerbin-Jool

In low Kerbin orbit with 905 m/s of delta-v remaining. This final maneuver isn't the one I ended up using. 

Mun assist kicks my orbit far above Kerbin where I use a second Mun assist to eject into a 5:4 resonance with Kerbin. I could have used a set of three Mun assists instead of just two, saving 12-13 m/s, but I didn't because my timing is lazy.

Five years later I encounter Kerbin, turning my prograde velocity into retrograde velocity, and also getting some more retrograde velocity from the Mun. This puts me into a 4:5 resonance.

Four years later I encounter Kerbin and the Mun again, dropping my orbit below Eve. Here, I neglected to time the transfer window properly so I have to wait a long time before getting the Eve assist. I think this Eve assist is actually more effective than a direct transfer would be since I have more radial velocity than a standard transfer?

Here, I have the Eve assist and two Kerbin assists set up. However I lose a bunch of precision due to using high time warp in the inner system and also warping across SOI boundaries. The Eve assist is set to give me a Kerbin assist two orbits later, and then another Kerbin assist one orbit (three years) later.

Final Kerbin assist set up - Jool wasn't in quite the right place (because again, lazy timing) so I have to raise my orbit quite a bit higher than normal with this last assist

Tylo and Laythe assists to capture in orbit around Jool

And here we are in Jool orbit. 50 m/s remaining, 905 m/s to start, 855 m/s expended between Kerbin orbit and Jool orbit.

I can actually see this path as being quite useful. While it takes a lot longer, and a lot more careful planning, than a K-E-K-K-J route, it also saves nearly 20% of the delta-v needed.

A further advantage to this path is that there is no minimum TWR required since you can just do periapsis kicks until you encounter Mun. This means that this is near ideal for low mass missions where TWR is a tradeoff with delta-v.

Edited November 27, 2020 by camacju