The Gary Flandro challenge

[Aegrim]

Gary Flandro is the guy who realised Voyager could slingshot itself around the solar system and visit all the other planets with very little fuel by comparison.

One thing I'd really like to do but lack the ability is to figure out how to do something similar in KSP.

I guess somebody with some Excel skills might be able to figure it out, we'd need to some maths to figure out when transfer windows from kerbin to planet A, results in an arrival at planet A during a transfer window from planet A to planet B.

I guess planet A could be Eve, Duna, and/or Dres, with planet B (and C?) being Jool, Duna, and/or Dres.

Maybe even a flyby of Kerbin after Eve, like recent Mars mission that's name escapes me.

(PS - I didn't put this in the challenges forum since it's not a challenge to build a craft that does something)

I guess gold goes to whoever figures out how to do it with the least dv?

Edited October 20, 2014 by Aegrim
links galore

[Aegrim]

Nobody got any idea how to figure this out?

[GoSlash27]

Well... it's a traveling salesman problem. I don't know how we'd go about solving it.

Your best bet might be to open it up as a challenge. Fly-by on the most planets with a single craft, something like that.

Best,

-Slashy

[K^2]

Excell won't cut it for this one. There are too many parameters to search on. I might be able to write a custom program that does a search by trying a whole bunch of possible start dates. I assume we can chose arbitrary starting time in the KSP world? And the challenge is to visit SOI of each planet, right? The Eve - Duna - Jool series of fly-bys should be fairly straight forward. The challenge would be in including Moho, Dres, and Eeloo in the search.

GoSlash, I'm not sure if this is a traveling salesman. There are a couple of permutations possible along the way, but your starting options are greatly limited. The delta-V reduction dictates that your first fly-by should be Kerbin. That will only give you enough boost to reach Duna or Eve. And going to Duna first makes visiting Moho and Eve very complicated. So Kerbin - Eve - Moho - Duna pretty much have to be visited in this order. And you'll need Jool fly-by to reach Eeloo. So your options are visiting Dres before or after Jool, which might not even be an option depending on where Eeloo is.

What does pick up the NP complexity here is where to budget your burns between fly-bys. But I don't think that is even solvable. I would go with "zero" delta-V plan. That is, assume that any delta-V change required to reach your next planet is due to fly-by. The only fuel usage is then due to corrections you have to make to hit the right part of your next target's SOI. Fuel requirement for the mission should then be the Kerbin escape budget. Perhaps, even just Trans-Munar if you want to include one more fly-by.

With "zero" delta-V plan, the algorithm would simply chose the next good Eve fly-by date, and see if it can make the necessary fly-bys. Then pick the next date, try again, etc. If it finds a solution, it will consist simply of series of periapsides you need to hit on each fly-by.

Edited January 26, 2015 by K^2

[Aethon]

Here's a semi-relevant video demonstration that covers some of the questions you have.

Edited January 26, 2015 by Aethon

[Neil1993]

I have been trying to build a Matlab simulation which models the motion of the planets (on rails) and has the capability to predict the motion of a spacecraft using the n-body problem. However, I would need to create a completely new input file for the KSP planetary system and I think that the fact that KSP models the orbital physics using spheres-of-influence would make my model useless (or at least inaccurate) for predicting in-game maneuvers.

[Aegrim]

Currently using this mod

http://forum.kerbalspaceprogram.com/threads/104280-0-90-Outer-Planets-Mod-%281-4%29-Unique-biomes-and-300-science-blurbs-17-Jan-15

I think the starting year though means the planets are in completely the wrong positions in relation to jool and the version of saturn.

About to send a probe to it, but i really wish it was passing jool on the way