Congratulations on your landing! Just to concur with what the smart guys said up there, those radial thrusters do have an awful efficiency. I usually design multi-purpose landers and make sure that they can at least land on Duna. I have to check if that still works on 0.20, but it should be possible build lander with *a lot* of Delta-v powered by two nuclear engines that has enough thrust to land and take-off from Duna. I can't find my trusty 0.18 nuclear lander on the forums any more, so I won't be able to show it off... Plugins such as Kerbal Engineer are really helpful during the design process, because they can show you your thrust-to-weight ratio on all the Kerbol celestial bodies for example. Anyway, good luck on your rescue!