Duna North Pole Rescue

[Halam]

I have a challenging problem that I'd like some ideas with solving. I have a lander with a tourist & pilot on the north pole of Duna and I am unable to get them to all the way back to orbit to rendezvous with the "go back home" ship. (My vehicle setup is a carbon copy of Apollo configuration; Saturn V rocket stages, with separate CM & LM modules. So right now the LM (or "DM" in this case!) is sitting nicely at the pole, and the CM is waiting patiently in a polar orbit. I had previously already tested this setup on Duna, and it was fine for an equatorial landing and re-ascent to orbit but I've found out the hard way that I need much more dV to make it back to orbit from the north pole.  

As mentioned, the lander is based on Apollo's LM so is made up of a terrier engine descent stage (that still has fuel remaining), separator, and the ascent stage is an MEM with a poodle engine. There is a docking port on the top of the MEM. 

Since the tourist can't EVA, I can't land a new ship nearby to pick them up. Neither can I land a rover, drive them elsewhere, and take off from there on a new ship - again because the tourist can't EVA. So I am stuck with having to somehow physically get the existing LM/DM back to orbit with the tourist inside.

One potential solution I am thinking of is to build a tall "heavy lift" rover on vertically extendable hydraulic wheels, land it near the LM/DM, park it over it, pick it up by mating a docking port on the underside of the rover with the one on the top of the MEM, and then drive it to the equator, drop it off so that it can attempt to take off to orbit from there. 

I have tested this solution at the space center with the same lander and an initial design for the Heavy Lift Rover and it seems to work fine in theory on KSC's runway. But considering I'd have to somehow land this monster rover on Duna, then drive it all the way to the equator seems daunting. 

So that's basically it. Am I overthinking this and have overlooked a very basic solution, or is there any other way to solve this one?

I don't want to abandon the tourist as he is part of a much larger contract, and also the satisfaction of solving this one would be immense. 

[James Kerman]

Welcome to the forum @Halam.

I've moved your question to gameplay questions. I would try building a refuelling rover or orbital vehicle fitted with the Klaw (be sure to test extensively on Kerbin before you attempt the mission).

[AHHans]

A warm welcome to the forum from me too, @Halam.

Are you sure you cannot get into a polar orbit from there? I'm sure that you cannot get into an equatorial orbit, but if you burn to the azimutal direction of your orbit-prograde vector (which will change during your ascent) you might get into some kind of orbit. (At the poles the rule-of-thumb of burning to 90 deg azimuth is not particularly efficient.) Once you are in any kind of orbit, rescue missions become a lot easier.

Otherwise the simplest solution is probably indeed what @James Kerman suggested. If there is some ore at the pole, then I'd suggest to make it a mining refueler, i.e. don't bring the fuel directly, but bring an ISRU / drill / thermal-management / solar-panel set. It might be actually lighter than bringing the fuel and it has the advantage that newly generated fuel is not limited by the fuel transfer rules that might prevent you from pumping fuel through the Klaw.

I like your idea of picking up the rocket and driving it to the equator, very Kerbal! But probably also quite hard (Aligning two docking ports on the surface isn't easy!) and tedious (Driving on the surface all the way from the poles to the equator will take a long time.).

Other solutions would be:

• Don't dock a ground-transportation rover to your craft, but a lifting rover that can lift it into orbit.
• Dock (via the Klaw) a rover with an ascent stage that can get into orbit on its own. Once you are attached via the Klaw, then you can transfer them to the new craft. (Yes, Kerbals can crawl through a Klaw. Don't ask me how!)
• Same as your idea, but use a (solar powered?) plane and not a rover. Flying on Duna is not easy, but can be done. If the plane is radio-controlled (i.e. a probe with no Kerbals in it) you could also use it to give yourself a little bit of extra delta-V by launching from the air and not landing first. (Not colliding can be a bit tricky, but it is not that hard.)

 

[Pecan]

How are you at rendezvous and docking?  My thought would be to simply launch the ascent vehicle into the longest (time) sub-orbital trajectory you can then catch it with the CM.  Simply launching straight up might give you hours before the thing falls back to its inevitable doom but who cares, as long as you have time to rescue the Kerbals with the CM?  Without knowing how much dV you have the viability of this can't be determined but it's often a lot easier than you'd think.

[Halam]

Some good ideas there to get me thinking, thank you all. I'll try a few more attempts at getting to orbit and docking as you've suggested. Failing that I'll revise my initial plan and come up with a new rover design with a more powerful ascent stage.

I didn't realise Kerbals could transfer through the Klaw, that will make the solution to this much easier. 

Thanks again, and I'll let you know how it goes.