Help getting to Minmus!

[Eyekonn]

Hello fellow Kerbinauts!

I am a new player to KSP and have recently build my first ship and landed on the Mun. Now I have set my sights on Minmus, but I am having a hard time trying to find the transfer orbit for it. Anyone have any tips?

Thank you!

[TranquilTempest]

Very similar to the transfer orbit to the mun, but you have to arrive at one of the ascending/descending nodes the same time minmus does, push an ascending/descending node to where you want to encounter minmus, or match planes with minmus before making your transfer burn.

Edit: here are some images of the second method. http://imgur.com/a/4LXR3#0

For the first method, you wait until minmus is about 1/6 of it's orbit before either the ascending node or the descending node, and make your burn such that you get to the node at the same time minmus does.

Matching planes is probably easiest, but it's inefficient unless you launch directly into the same plane as Minmus.

Edited April 3, 2014 by TranquilTempest

[Eyekonn]

Ok, I have not tried to align myself to the orbit first. I have just been throwing out a big orbit and just hoping it catches on. Thank you!

[KerikBalm]

Or just match its inclination before even starting the transfer maneuver....

This doesn't work for other planets, but it does work for minmus.

Set Minmus as a target, place a maneuver node at the "ascending" or "descending node", at that manuver node, set a burn normal or antinormal (ie pointing "up"/north, or "down"/south) until the ascending/descending node reads 0.0/ NaN/ starts to move (the more precisely placed your maneuer node is, then the closer the point where the asc/desc nodes start to move is to when you'd have perfectly matched inclination, if you placed it perfectly, then the nodes will suddenly swap as you make your burn a bit longer)

*execute the burn*, possibly repeat if your inclination is still off by more than say... 0.5 degrees (ie look at where the asc/desc nodes are post burn, do another correction burn at that point)

*transfer to minmus as you would to mun with a simple appropriately time prograde burn, and retrograde capture burn.

Edited April 3, 2014 by KerikBalm

[cerberusti]

There are a few ways to do it, from lowest to highest DV requirement:

1) launch into the same inclination

2) intercept it at the AN or DN

3) make a correction burn on the way

4) match the inclination once in orbit, then intercept

If you are intercepting at AN / DN, you can overshoot its orbit slightly and arrange for your return trip to cross the node. This is very cheap due to how far out it is, and lets you fine tune the encounter time to make sure minimus is where you want it on intercept.

It is definitely worth a visit, I just pulled well over 6k science off of minimus in one trip by visiting all of the biomes and packing a lander can with all possible experiments for return.

[Pecan]

Eyekonn - it is harder to get to Minmus because of its inclined orbit. Once you get there though it's easier to land on and return from so the 'easy' sequence is i) Mun orbit, ii) Minmus orbit/landing, iii) Mun landing. If you've already landed on Mun the only thing to watch out for on Minmus is the very low gravity.

[capi3101]

I usually go to Minmus in a fairly inefficient manner. It's pretty easy for beginners though - here's what you do:

1) Once you're in orbit, go to the map screen and tilt the camera so that you're looking at Kerbin's North Pole. Target Minmus.

2) Turn the camera until Minmus is in at the three o'clock position.

3) Set a maneuver node at the six o'clock position and pull prograde until the orbit indicated touches the orbit of Minmus from that perspective. If you're lucky enough to get an encounter by pulling prograde, great; just do that.

4) Assuming you didn't get an encounter, place another node at either the ascending node or descending node, whichever one you come to first.

4A) If the node is past about a third of the way to Minmus, stop, delete your node, wait one orbit and try again. Do this as often as necessary.

5) Here you want to to pull normal or anti-normal; you want the value of the node to go down to zero, or at least to 0.1 or 0.2. Once it's there, you should see the close approach chevrons. Pull the prograde/retrograde markers until you get an encounter. If you still don't get one, pull on the radial in/out markers, or fiddle with the positioning of your nodes until you get an encounter.

6) With your two nodes set up, burn as indicated. Be willing to re-do the second node after the first burn.

That'll get you there in the early going. Later as you gain experience, you can start attempting to combine the inclination and transfer burns into one.

What just occurred to me is this -

1) Get in orbit, go to the map screen, target Minmus as above.

2) Set up a maneuver node any old place along your orbit. Pull prograde until 930 m/s is indicated.

3) Move the node around until a Minmus encounter is indicated.

4) If have sufficient time, burn as indicated. If not, try again in another orbit/half-orbit.

That's going off the latest delta-V map that says you need 930 from a 70k orbit to a Minmus transfer, and unless I'm mistaken moving the node around will ensure that you find one of those spots where the burn occurs at the node. Something worth trying anyway.

[Streetwind]

That second method works with the Mun but not with Minmus, because it doesn't account for inclination.

[capi3101]

Doesn't Minmus's orbit cross Kerbin's equatorial plane at some point in it's orbit? I thought that's what the nodes indicated......and if you set up a maneuver node so that you get to Minmus at the same time it's crossing the equatorial plane, you should get an encounter, shouldn't you?

Or have I not had enough coffee this morning?

You're probably right; I haven't tried this myself so I shouldn't be recommending it to anybody - OP, if you go with any of my advice, go with the first method.

[cantab]

The simplest method:

Launch to LKO.

Set Minmus as target.

Set a manouvre node at the ascending or descending node. Whichever is highest above Kerbin, if there's a big difference. Drag the normal or antinormal (purple) handles until you see the AN and DN swap places. Make that manouvre.

Now your orbit is aligned with Minmus's, just encounter it like you would the Mun.

This isn't the lowest delta-V method, so pack a few hundred more m/s than the delta-v map tells you.

Doesn't Minmus's orbit cross Kerbin's equatorial plane at some point in it's orbit? I thought that's what the nodes indicated......and if you set up a maneuver node so that you get to Minmus at the same time it's crossing the equatorial plane, you should get an encounter, shouldn't you?

The Ascending and Descending nodes indicate where Minmus's orbital plane crosses yours. Typically you'll be in an equatorial low Kerbin orbit, but not always. Edited April 3, 2014 by cantab

[Javster]

A slightly different point: you can shrink you Mun lander by a bit and move the fuel to your transfer stage.