Gotta Rescue Jeb!

[benikens]

Quick explanation, I was returning from the mun, ran out of fuel, was pushing ship with jetpacks, then re-encountered the mun and it flung Jeb into a weird orbit. I now want to bring him home. Also I've never performed a successful intercept before but Jebs life depends on this.

First question, should I decouple my engine from the lander? If I decouple will it be easier for me to push the ship and modify the orbit? I really want to change the orbit so its not longer so close to the mun as a previous rescue attempt also went awry thanks to the mun's SOI.

Secondly, If I'm planning an intercept with a body in a oblong orbit what is the correct way to match orbits? Here's what I attempted before:

1. Orbit Kerbal

2. Change plane to put ascending/descending nodes at 0.0

3. Extend my orbit such that my Apoapsis is aproximately ontop of Jebs Periapsis

4. Burn at my Apoapsis to push it out towards Jebs Apoapsis

[Wemb]

First question, should I decouple my engine from the lander? If I decouple will it be easier for me to push the ship

Can't say if it'll be easier - but it should be more effective, as you'll be pushing a less massive craft, and so will push it futher/faster than you would with the engine.

Secondly, If I'm planning an intercept with a body in a oblong orbit what is the correct way to match orbits? Here's what I attempted before:

1. Orbit Kerbal

2. Change plane to put ascending/descending nodes at 0.0

3. Extend my orbit such that my Apoapsis is aproximately ontop of Jebs Periapsis

4. Burn at my Apoapsis to push it out towards Jebs Apoapsis

First, try and launch into the same plane as best you can before to make 2 as cheap as possible. Secondly, once you're in an orbit, you'll need to do a Hohmann transfer to get to Jebs orbit as you describe - but you may need to orbit several times to get the timing right. The timing is just as important as the orbit - you can't 'catch up' to someone when you're in the same orbit as them, so you must plan your transfer to reach Jeb's orbit at the same time as he gets there too.

Wemb

[Superfluous J]

I covered rendezvous in part one of my docking tutorial series. Your rendezvous is more complex what with the Mun in the way) but other than that wrinkle, every rendezvous is essentialy the same 3-step process. Align orbits, get the orbits touching, then burn so you'll get a close approach.

You probably won't need part 2: Approach or part 3: Docking. When you get close, just burn hard "retrograde" in target mode until the relative velocites are near zero, then EVA Jeb to go to the new ship. However, Part 2 will show visually how to come to a stop a few meters from Jeb's craft.

[dbmorpher]

Make sure you remember to take all that tasty science with you! Wouldn't want to waste a good number of funds.

[Sharpy]

The first part was covered by others. The second part depends on inclination of Jeb's orbit.

If it's less than 40 degrees from the rescue craft, you can do it in this order. (and it really should be; you should launch the rescue mission into a roughly the same orbit; performing the launch when KSC passes under Jeb's orbit too.)

If it's more, then you'd need to make an excessive burn to change the inclination. Better extend your apoapsis a lot, trying to get one of the nodes (ascending, descending) as far as possible from Kerbin, then equalize the plane.

As for matching the orbits: don't. You'll have an utter hell of finding the encounter. Make the orbits intersect (PE below PE of the other, AP above the AP of the other, preferably one pair quite close, the other more distant) and be not very similar. Then seek a good encounter. Matching the orbits without an encounter will make it take ages until you meet the target. You match them only once you're some 5km away or less (by burning retrograde relative to target).