Planetary Transfer Question

[Tuck00]

I have only done a probe to Duna and Eve, both were done like a orbital rendezvous where I got in the targets orbit and just made my orbit of Kerbol a bit lower to catch up with the planet.

I have installed Kerbal Alarm Clock. It tells me I have a window for Moho in 19 hours. I have played with maneuver nodes trying to get an intercept, but can't get it. When Alarm Clock says it's time am I looking to get an intercept on the opposite side of Kerbol on a Kerbol orbit, or come straight off a Kerben orbit to Moho.

Hope that all makes sense.

Thanks

Tuck

[MKI]

Kerbal alarm clock launch windows aren't perfect because of moho's inclination and eccentricity.

I use this for most launch windows, since it has pictures and simple calculations. Use this and see if you can play with the nodes to get your rendezvous. http://ksp.olex.biz/

[federally]

MKI is correct and I love the tool he linked. It helped me get my first successful interplanetary missions.

[Tuck00]

Thanks MKI I saw Scott Manley's video using this site but was afraid to try it, I will give this a shot tonight.

[Kasuha]

I definitely recommend alexmoon's calculator

http://alexmoon.github.io/ksp/

In current version you can specify any starting or target orbit, including elliptic and/or inclined ones. Or you can set up that you don't care about target orbit because you're going to aerobrake.

Edited March 24, 2014 by Kasuha

[Superfluous J]

Also, Moho's a much harder target than some of the other planets because it's so small and fast. You can be pretty close to an encounter and KSP won't tell you. Practice with Eve or even Jool.

Even with the help of calculators it can be annoying at times, but keep it up. It does get (a bit) easier with experience.

[cantab]

The other key thing is that your ejection speed and your ejection angle matter. So you can swing your ejection burn round your orbit however you like, change how much dV you apply however you like - but you need to get both right for the intercept.

Hence, a calculator helps.

[Kasuha]

Also, Moho's a much harder target than some of the other planets because it's so small and fast. You can be pretty close to an encounter and KSP won't tell you.

What you need is to get the inclination marker and both closest approach markers to point at the same place. Even with semi-precise ejection it is possible to correct it using additional small burn and then RCS.

The point is, Moho is about the most distant planet in the system, in terms of delta-v. People are often surprised by amount of dv needed to brake. The calculator at least tells you what you can expect. But it is still better to have solid reserve.

[StrandedonEarth]

I also use KAC. Another suggestion is to bring your orbit down to Moho's, then plot a correction at the inclination marker. Hope that helps.

[Kryxal]

For that matter, THAT method allows for low-TWR engines to be used more effectively, since you can make a long burn at periapsis to get the intercept and you'll have a lot less delta-v to get rid of as you go screaming into Moho's SoI.