Zen and the art of hunting for slings.

The video 2009-EVVEJSN shows the mechanics of setting up the slings. However what it doesn't show is how the initial eject to Venus was found and what order of slings was set up to create the cascade of slings. If it did, it would be a HUGE video lasting perhaps well over an hour since the actual time spent finding this setup was probably 40 minutes of very rapid clicking and it would have been much longer if I had to explain what I was doing as I went along. I will however recap where I went and what dead ends I encountered on my journey to find this sling cascade.

I started with today's date March 25th 2009 and decided to look at the possibility of some inner slings with perhaps the ability to end up heading to the outer planets. I could see that Venus was in good position to head there either now or very soon in the future. I set up an eject plan to leave in 1 weeks time and I would drop inside Venus' orbit and rise up to meet it after 3/4 of an orbit. This was done and a sling was then checked for Venus a second time 1 full orbit later. This showed an easy sling so I then headed off to Earth. I found this sling but the plane change was going to be so severe that the sling from Venus to Earth was below Venus surface. Dead end.

So I tried Mercury as a target to perhaps consider just a trip there as a way to show slinging in a video. But Mercury also was going to prove tough with the reuired plane change. Dead end.

So the goal after the second Venus sling was then to target Mars. I did find a way to Mars but it had no way to get to Earth after that without waiting a long time going at least 3 orbit out past Mars. Dead end.

So I backed up to modify my search to the first Venus Venus sling and instead of doing a full orbit, I opted to try hitting Venus after 3/4 orbit (Venus does 1 and 3/4 orbits in the same time).  From there I chose Earth and found a reasonble solution to hit Earth and quickly set up a sling from Earth out toward Jupiter. It did show an easy climb to Jupiter's orbital height but I was unfortunately far ahead of Jupiter so without a huge deep space maneuver (not very pure)  I considered this something intriguing enough to consider modifying how I get to Jupiter. Perhaps an initial eject to Venus that is more energetic so that the energy from it gets me higher to allow ultimately higher slings all the way through the next passes at Venus and Earth so that I rise higher heading to Jupiter allowing Jupiter more time to gain on me. I did this with somne added outward in the initial eject variables from Earth to Venus. This also meant changing the prograde quite a bit. But soon I found this to not be a solution to how to delay slightly my arrival at Jupiter height. But not to give up yet.

So I tried the same extra energy but this time, delay the eject date an extra 1 week so the time to deparure would be 2 weeks from the scenario starting date. I modified all eject motion variables a bit to make the first Venus encounter happen and then adjusted each sling to get the same order, meaning after ejecting from Earth, it was Venus, Venus, Earth, Jupiter. But this showed an even worse arrival position at Jupiter. Hmmm? But out of this failure comes a solution. Even though my gut instinct said to delay the initial departure, this delay made it worse, so perhaps advancing the departure time to being sooner it would get better? This is a basic part of searching for slings... make a change and if it get's better keep it, if it gets worse, then reverse the change. So I pulled the eject date back to just a few hours from the scenario start, and again readjusted the eject variables to hit Venus. Then readjusting the subsequent slings always watching I was not hitting any atmosphere during a sling I found that it indeed had a solution to sling to ultimately encounter Jupiter. Nice. Now we are successfully with EVVEJ (using the first letter of each planet we are near)

But not wanting to stop there I wondered about the possibilities of slings past Jupiter. I tried Saturn and immediately had an easy solution. So then I tried Uranus after Saturn but unfortunately Uranus was not in position to be a target. But Neptune was in position so the total sling cascade ended up being Earth, Venus, Venus, Earth, Jupiter, Saturn, Neptune. I called this 2009-EVVEJSN.

Happy sling hunting!






















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