[HELP] Rescue Mission

[B4CK]

Hi guys,

so I'm quite a newbie to KSP and I need to recover from orbit one of my Kerbals that ran out of fuel.

I tried for weeks now - can anyone take my savegame file and help me? :)

[andylaugel]

I'm not going to take your save, but I'll help out as best I can.

What can you tell us about your stranded kerbal's orbit? Are they orbiting Kerbin, the Mun, the Sun, or something else? What kind of Ap (highest point in the orbit) and Pe (lowest point) do they have? A screenshot can help.

Anyways, here is what I would do:

First, design a rocket with room for your kerbal and enough dV to reach your stranded vessel and return. You may need to go into the crew tab while in the VAB and drag an auto-assigned crewman off your rocket. It'll help if there is an easy to access hatch, which is only a problem with the Mk1 Crew Cabin--which can be mitigated with some crew transfers.

Next comes the rendevous. Most LKO rescue contracts get into a 80 km orbit around Kerbin's equator heading east. If that is your case, then a typical launch where you slowly tip over to the east should do. If your target is going west or polar, you'll want to wait until the target's orbit is over your launch site and then turn the appropriate direction, watching from the map view. Once you're in orbit, follow these steps:

• The inclination burn. Select your stranded vessel as your target on map view. The AN and DN nodes on both your and its orbit will be connected by dotted lines. Hover over those nodes, and you'll get the angle between the planes of their orbits. Burn normal or antinormal at those nodes to reduce that angle to 0--putting both orbits on the same 2-dimensional plane.
  
• The intercept burn. Add a maneuver node to your orbit. Drag the prograde or retrograde arrows until your orbits touch. Click and drag the center around until either the orange or magenta markers touch--same color to same color. Those are the points where your new orbits will bring the two crafts closest together. You may need to fiddle around here, but you should be able to get an intercept within 1km or less. Do the burn. Make fine-adjustments looking at map view if necessary.
  
• The rendevous. Click on a point in your orbit before the rendevous and click "Warp to Here." If you have fuel and want to take your time, you can match velocities. Click on the word "Orbit" or "Surface" on your navball until it reads "Target." (If that doesn't appear, re-select the other craft as your target on map view). Point retrograde. When you think the time is right, burn until you reach 0.0 m/s. You've matched velocities, making your crafts mostly stationary to one another (orbital drift is a thing). Use the square bracket keys '[' and ']' to switch between craft. Once you are within 2.2 km, you should be able to control the stranded craft and its kerbal. Have your kerbal go EVA. Press 'R' to activate his jetpack. Press space to let go of the stranded craft, and use WASD & Left Shift/Cntl to go to the rescue ship and board it.
  
• Go home.

I hope that helps. Let me know if you have more questions.

[andylaugel]

Oh, there is an alternative to having your stranded kerbal go EVA. You can dock with it. And you can use the Advanced Grabbing Unit (the Klaw) to dock with anything, even if it lacks docking ports. Here is my typical LKO rescue ship. For higher orbits though, it'll need to be a bit beefier.
https://steamcommunity.com/sharedfiles/filedetails/?id=732892664