How To Rescue a Kerbal?

[Awesomea1432]

Ok, I sent a kerbal to the Mun and was able to successfully land. I was then able to get back into a kinda polar orbit, with barley any fuel left. My kerbal has no hope of getting home! I need help (maybe some tips, maybe a rocket design) for a rescue mission to pick Bob Kerman back to Kerbin!

[Uberick]

So, if I understand the current situation: Bob is currently in a Polar orbit of the moon and needs a craft to rendezvous and rescue him?

If that's the case, he should spend his remaining fuel trying to circularize his orbit. After he's done that, any remaining fuel should be spent trying to remove any inclination change in regards to Kerbin(Set Kerbin as a target, as then set up maneuver nodes at the Ascending or Descending nodes. Use the pink triangles on the maneuver node to change inclination.)

Okay, so once That's done, Bob's done all he can do; it's time for the folks back home to pick up the slack.

The ship below can do this mission with about 1000 m/s dV left over, plus another 350 dV of RCS fuel. I don't know how experienced you are at rendezvous, so I packed a ton of RCS.(Make sure to put your RCS thrusters with four way symmetry around your Center of Gravity, if they are properly placed it will make translation easier.)

This ship is basically a one man command pod(make this your first part, that way the second, three man command pod will spawn empty so we have room for Bob), on top of a three man command pod, on top of two 1440l fuel tanks and a Skipper engine.

I use four more skippers paired with 2 fuel tanks and three solid boosters each to put it into orbit(not the ideal solution, but it works fine and is fast to orbit).

If you want to use your own design, the design objective is to get a pod with an empty seat and parachutes so that Bob can EVA over, get on a Kerbin intercept, and splashdown to safety. You can do this with probe cores, as part of a lander mission, etc

Put 4 radial parachutes on the three man pod, separate it from both the fuel tanks below it AND the capsule above it with decouplers(add struts for stability). What we're going to do, is fly to the moon, rendezvous with Bob and have him EVA over. Once he's in the three man pod, we will EVA over our other Kerbal(the one who piloted the ship) to the three man pod as well. Then we will plot a trajectory from the moon back to Kerbin, such that we will be captured by Kerbin's atmosphere and return to "Earth". Just before entering the atmosphere, we will decouple the three man pod from the rest of the vehicle, and the radial parachutes will take care of our decent.

I assume you know how to get to the moon, since you've done it already. The only thing different about this time, is that once you arrive you're going to set up your orbit to match Bob's orbit for a rendezvous. Plop a maneuver node and change the inclination(pink triangles) and pro or retrograde(green circles) until you are aligned with Bob's orbit.

Boom! Set up a rendezvous, have Bob spacewalk over, and burn home!

If you haven't done a docking or rendezvous yet, I highly recommend looking up Scott Manley's docking video on youtube(or any of his videos)

If you'd like further info, I can "run the simulator" and take photos to highlight a particular area. Docking, especially if you haven't done it before, can have a steep learning curve.

Good luck!

[Akalaël]

Nothing more to say. The key to rescue is docking, and this is the part the more difficult in KSP.

Or you can EVA when your ships are close one each other, but the controlls on EVA are rather difficult I find (I even lean to perform EVA after Learning the docking stuff)

Good luck in your attempt comrade

[xandski]

As said above, your two options are docking and EVA. Both require a rendezvous with the stranded ship which can be difficult to set up, particularly with an inclined orbit. I also prefer the EVA method partly as it means that 1; you get all of the Kerbals in one ship thus eliminating the wobble while under throttle from having two docked vessels and the potential for a docking port failing when re-entering the Kerbin atmosphere (if you keep both ships attached) and 2; it also looks really cool if you're recording it.

There is, however, a third option... an unmanned fuel truck. Send it up, dock it then transfer the fuel across and have the Kerbal come back under his own steam. This, like docking a manned rescue vehicle, does require both ships to have a docking port but I'm sure your ships have one as standard

Good luck and let us know how you get on

[lohchuantuck]

There is another option, which I use a lot. I took a screen shot, and salute him for sacrificing for sciences.

[Awesomea1432]

Thanks! I can't wait to try it out!

[Awesomea1432]

Update; Bob is on the ship! I am just working on bringing him back. Thanks to everyone! You're all a big help!

[magnemoe]

Nothing more to say. The key to rescue is docking, and this is the part the more difficult in KSP.

Or you can EVA when your ships are close one each other, but the controlls on EVA are rather difficult I find (I even lean to perform EVA after Learning the docking stuff)

Good luck in your attempt comrade

found that the easiest way to do eva is to point camera against target, this will orient the kerbal, use left shift and control to go up and down, A and D for left and right, W and S to speed up or slow down.

Do not go to fast, just point your kerbal at the hatch or ladder and press F then close. If hatch is on backside its often best to pass the target and turn.

[Uberick]

In regards to EVA, as said above^, it isn't that tricky if you take it slow. Use the right mouse button to center the the camera on your target, and then give W a short press. This should re-orient your kerbal pointing towards the ship. It might take a while for him to get there, but in space, slow and steady wins every time. If he's heading towards the ship and the hatch is on the other side(or oriented in some odd fashion), you can always swap to control of the ship with [ and ] and change its orientation.

I recommend quicksaving, and then taking Bob out for a couple EVA practice runs. Get used to circling around your ship, going up and down, and getting a couple hundred meters away and returning. When you go back to the command pod it will refill your EVA RCS fuel back to 100% for free.

I use EVA with spaced command pods(every 20km or so) on low gravity planets to move Kerbals from one point of interest to another. It's faster than rovers, and you don't have to keep sending fuel down because the RCS replenishes for free. On many super low gravity moons, you can even put a kerbal into a pretty serious orbit with just EVA thrusters. On Eve's moon, you can even achieve escape velocity.

Once you get the hand of EVA, it's much easier to EVA a kerbal from one vessel to another(even over a couple hundred meters) than it is to dock.

[CalculusWarrior]

...it isn't that tricky if you take it slow.

But it's so much fun to send your kerbal flying into the side of the craft at 50 m/s!

[IllicitMedic]

Why do people over do it for the Mun? That rocker is WAAYYYYYY to big for a Mun mission.

[Uberick]

But it's so much fun to send your kerbal flying into the side of the craft at 50 m/s!

Ha. I havn't done that, but while I was exploring Dres with RCS, I flew too fast and turned one of my Kerbals into dust. . .

[Uberick]

Why do people over do it for the Mun? That rocker is WAAYYYYYY to big for a Mun mission.

That particular one is overbuilt assuming a pretty generous margin of error. Tons of fuel, tons of rcs, high thrust engines for ease of use.