[Tutorial] A perfect munar slingshot from kerbin

[Markus Reese]

Hi guys, I was heading out on my first official planetary mission set when this happened.

The apo I am currently at is clearly visible, and this is during my de-orbit from kerbin burn. Mun is eclipsed by kerbin pretty much. I started my burn at the sunset line. The resultant of this slingshot would place my Kerbol orbit periapsis (I forgot to screenshot) about half way between eve and kerbin orbits almost. Alas, I am heading to dune so this path isn't really any use to me. However, I can only assume that if it was done the other way, with mun on the sunside, and the burn taking place at sunrise, this can really help alot. If timed correctly and you hit the apo closer, I suspect it could be done even better.

Note the very narrow apo. Being almost stalled on mun capture means an intense duration of pull, plus relatively close to the surface. In fact, with slight course adjustments, It was <90km from munar surface. Should really help my big rockets, this might become a new standard for planetary launch should I be able to do it consistently. With better alignment, I expect even greater results.

Fly safe :cool:/

Edit edition! Did a flyby with another craft and launched it to "stall" Apo just past munar orbit. Gravity caught, pulled me into a sharp orbit around mun with an Peri of onl 11km! Resultant was an Apo in kerbol orbit of 13.3 mil km (kerbin orbit) and a peri of only 11.8 million.

If this is possible elsewhere, then this strategy could be applied to leaving any Munar body to escape planetary at considerable fuel savings.

Edited October 12, 2012 by sal_vager

[Limit]

I did alot of testing in 0.16 for slingshots in preparation for interplanetary travel.

Its all about pre-planning. You need to make sure the moon is in the right place in order to escape kerbin prograde or retrograde (ie head away from the sun or closer to it). I try and get my mun periapsis at about 2km from the surface (as close as possible), then when at mun periapsis I do another burn to get my kerbin preiapis to about 70km (as close as i dare to the atmosphere). Then i finally do a burn a kerbin periapsis depending how far out I want to go.

[LegitBro]

why is your orbital trajectory purple? wait no, why are there 3 of em. the blue line, the yellow line and a purple one. is this a mod?

[pwnedbyscope]

no. the blue like is the current trajectory, the yellow is munar capture trjectory, and purple is munar escape trajectory

[whatisthisidonteven]

why is your orbital trajectory purple? wait no, why are there 3 of em. the blue line, the yellow line and a purple one. is this a mod?

In his settings.cfg file he has changed CONIC_PATCH_LIMIT = 2 to CONIC_PATCH_LIMIT = 4 or more.

[Szkeptik]

If you want to get a higher interplanetary orbit to get to Duna, launch from a 270 degree angle and sligshot as low above munar surface as possible. You can even get a little beyond Duna that way.

Also added extra, but almost impossible to get: Dual sligshot from Mun + Minmus can get you almost to Jool orbit. Only happened with me once though, and totally by accident.

LegitBro:

On the different line color thing: It's a setting in settings.cfg file. I don't know witch one, but you set it to a higher number and it will show you more predicted orbits like that.

[Fuzzy Dunlop]

The thing about slingshots is that they depend on the mass of a body. So the Mun can just about push you out of kerbins SOI, whereas you will probably spend more fuel targeting Minmus than it will save you.

Where you really make big savings is slingshots around Kerbin, Eve and Jool.

And remember you can always have more than one slingshot around the same body.

[SunJumper]

Well, Jool is the best for slingshots. Go down to 200km altitude, and you'll be quite close to solar escape...