A easier way to get into Moho's orbit.

[Grand Lander]

Its hard for me to get into Moho's orbit even Mechjeb has a hard time by just adjusting all the time, But after 30 minutes of waiting I give up and rage for the time wasted doing nothing. I go into a very closed sun orbit and Mechjeb just doesn't rubbish. Create a way to get into orbit the easiest way possible with little time using Mechjeb.

Edited September 24, 2012 by Grand Lander

[Excalibur]

I know of a simple way without using MechJeb, it's not the most fuel-efficient but does get you there with a reasonable fuel budget.

First of all timewarp on the launch pad until Kerbin is directly opposite Moho's aphelion. Launch into a low Kerbin parking orbit of your choosing, then use this calculator to figure out when to make your injection burn. If done right your perihelion should intersect with Moho's aphelion.

As soon as you've left Kerbin's SoI perform a plane change maneuver (either by pointing north or south on the navball's horizon line) until you have roughly the same orbital plane as Moho.

At this point you may not have a Moho encounter showing, so what you can do is perform either a prograde or retrograde burn at perihelion. This changes your orbital period to either allow yourself to be caught by Moho, or catch up with Moho on the next orbit.

Here's a gallery that chronicles one of my Moho landing missions, and should help you understand my method. Admittedly it is a little quick and dirty but it does get you there.

Also I'd recommend using an RCS-powered landing stage as conventional liquid engines tend to get rather hot down in Moho's tenuous atmosphere!

[Grand Lander]

Thanks, it worked on second attempt for me! Thanks! =)

[Excalibur]

Glad to have been of assistance my friend.

[Letum]

An even simpler way is to get into an orbit round the sun that is perhaps 1000km smaller than Moho's orbit and wait until you catch Moho up.

The down side is that it is not fuel efficient and will take a long time, depending on where Moho is when you start. The upside is that it is very simple.

[Markus Reese]

My usual tactic that really works for any orbit capture is follows. Some things have two ways depending on orientation of transfer burn. In this case, anything with variance will be Inner(Outer) transfer for relative to your orbit. Ideal if you don't like calculators.

The usual capture an orbit Try to launch a bit before the orbital planes of your orbit and your target orbit cross. It is ideal to have your orbit to be the same as target before this happens. Save a bit of fuel and exit counter kerbin orbit for inner planets. (prograde kerbin for outer planets)

Align orbit planes

Burn when at a point where you will arrive just a bit after (early) if you are aligned to plane, you can keep burning so your orbit will become just a bit inside (outside) your target's orbit which if you keep burning, you will (target will) catch up and intercept.

Should you be arriving early (late) then burn away (towards) your target to keep you a bit outside (inside) targets orbit until closer for a capture.

[Tim_Barrett]

Just slingshot around the Mun in the opposite direction of Kerbin's general velocity. Done.

[Excalibur]

Just slingshot around the Mun in the opposite direction of Kerbin's general velocity. Done.

As far as I know using the Mun or Minmus for a slingshot isn't as efficient as simply burning with the correct retrograde angle in LKO; due to the Oberth Effect. During the experimentals Tosh created a temporary guide that outlined using such a slingshot. Illecto (aka Scott Manley) posted the following response;

No no no no

DO NOT USE MUNAR SLINGSHOTS.

Essentially the velocity you gain from a slingshot around a body goes down as your spacecraft goes faster when crossing its orbit. You get the best energy gain when you are essentially standing still and the body catches up to you, swings your around its trailing edge and spits you out going twice its orbital velocity. This is great for travelling to Minmus, but since you're trying to exceed escape velocity you want to be moving faster still. As such the velocity gained by going round the Mun drops, it drops so far that the extra hassle of waiting for the mun to be in alignment is not worth it for the miniscule velocity gain

On a typical interplanetary burn you'll be moving 1-2km/s when you arrive at the munar orbit, which means the hyperbolic orbit deflection is going to be 1-2 degree at most (hyperbolic eccentricity will be about 10), giving you 1-2 percent of the munar velocity.

Now, if you decide to not burn in low-kerbin orbit so that you're moving slower when you arrive at the mun then you lose out because of the Oberth effect is stronger in low kerbin orbit. So, make sure your injection and capture burns are as deep inside planetary gravity wells as you can get if you want to get the most bang for your buck.

I would have thought a Munar slingshot the best way to go myself, until I read that post. From what I have seen, Scott knows his stuff.