Rendevzous

[Sidoz11]

need help doing a rendezvous...

I've landed on the mun plenty of times, so I decided to challenge myself so I'm going for an apollo 11 style landing on the mun, I can land fine, its the meeting up with the command module and docking, so if anyone can help I would be entirely grateful.

Edited February 12, 2014 by Sidoz11
Answered

[Taki117]

What are you having an issue with? Do you have RCS thrusters on your CSM?

[Sidoz11]

Yeah, my main problem is intercepting the Command modules orbit with my Lunar Lander, I've looked on youtube and the wiki but I still can't manage it.

[capi3101]

1) Go to CSM and note its prograde heading. Assuming it's still passing overhead, that'll be the direction in which you want to take off. If it's not in an exact equatorial orbit, expect to be off (the alternative is to make sure you don't launch until you know it's going to pass directly overhead; that can take a few Münar rotations).

2) Target the CSM. Launch when the CSM is about 150,000 m downrange or so. Circularize at roughly its same altitude.

3) Make a plane change correction at either the ascending node or descending node. This will be along either the normal or anti-normal heading to your prograde vector (set up a maneuver node and use the little purple triangles to set it up; assuming an eastward launch, north at the descending node, south at the ascending node). Get it to zero (or as close as you can manage and be prepared to try again the next time you hit a node).

4) Look at your close approach chevrons. Set up a maneuver node to burn prograde at the next -apsis (doesn't matter which). If the chevrons get further away when you pull prograde, stop and pull retrograde. Make sure when you're doing this that you don't send your periapsis below 10,000 m; if that happens, trash the maneuver and set it up at the other apsis instead.

5) Ideally you want to get those approach chevrons down to 0.0 kilometers, but anywhere below 1.0 kilometers is good and below 2.3 kilometers is good enough for a rendezvous.

That should get you your rendezvous. Have you ever done a docking maneuver before? If not, say so and we can walk you through that too.

Incidentally, add RCS to your CSM and LM; I can't stress that enough. You have to do fine maneuvering and you don't want to be doing that with main engines only.

I wouldn't worry too much about the need for extra delta-V for rendezvous and docking; if you've got a little extra in your LM's ascent stage, you should be just fine.

If you need design hints, check out the Doing It Apollo Style Challenge and look at people's designs. You can definitely get some good ideas there. I'd link you directly to my entry, but my attempt had a few problems and it was mostly done in the dark anyway.

One last resource for you: http://wiki.kerbalspaceprogram.com/wiki/Tutorial:_Apollo_11

Edited December 4, 2013 by capi3101

[Sidoz11]

Thank you, I have done docking before, I know the basics of it and can dock (occasionally xD), I'll give the rendezvous a go and tell you how it goes, thanks again for all of your help

[Taki117]

Why not do like the actual Apollo mission and have both the CSM and LM in the same vehicle? Would make your rendezvous easier, just detach the CSM from the nose of the LM, flip the CSM around, dock, and perform another flip to face the right direction.

[Specialist290]

I believe he's talking about the rendezvous approach coming from after the Mun landing in this case, Taki117, not the initial ET&D approach.

[Taki117]

I believe he's talking about the rendezvous approach coming from after the Mun landing in this case, Taki117, not the initial ET&D approach.

Ah, that's a different animal entirely. You can do this one of two ways. When you are done on the Man launch and place yourself in either a higher or lower circular orbit (it doesn't really matter which) wait until your CSM and LM are about 90 degrees apart (maneuver nodes help with planning) burn to intercept. And as has been mentioned before RCS on both the LM and CSM

[Sirrobert]

Download Mechjeb, and let it do the randevous for you. Observe what it does at each step, so that you may replicate it

[blizzy78]

FWIW, I have made an in-game rendezvous (as well as docking) tutorial that you might want to give a try. (see signature)

Also, "help me please" should be banned as a thread title.

[Sidoz11]

FWIW, I have made an in-game rendezvous (as well as docking) tutorial that you might want to give a try. (see signature)

Also, "help me please" should be banned as a thread title.

Yeah, sorry about that, its my first thread and needed help.

[SSSPutnik]

At least add Obi Wan.

[Vanamonde]

Sidoz11, if you click to edit the first post in the thread and then choose "go advanced," you can change the title of your thread.