I've done my first landing on Duna with a safe return. That was brilliant fun. My rocket was launched in two parts. First, a big orange fuel tank with a rocket engine at one end and a docking port at the other. Next, a small lander craft. They docked with each other ~100km above Kerbin:
Those two orange tanks at the side are actually left over from the asparagus launcher. They have a decent amount of fuel in them and they have fuel lines leading into the central tank, so I kept them attached for what is essentially free delta-vee.
Our heroes arrived at Duna 123 days later:
I transferred as much fuel and mono-propellant into the lander as it could take, and took it down to the surface.
Of course, Jebediah Kerman gets to be the first to walk on the surface of Duna. The command pod has 4 radial parachutes attached to it, and I used two of those to assist in aerobraking and keeping the lander oriented correctly. The remaining two will be used to land back on Kerbin. After doing whatever science stuff they came to do, Jeb, Bill, and Bob hopped back in the lander and launched to return to the fuel tanker.
That was a bit scary if I'm honest. The lander barely made it back into orbit, and by the time it got there, its fuel had run so low that I didn't have enough left to correct for orbital inclination or raise my orbit to the tanker. Well, if the mountain will not come to Mohammed... I had to switch over to the fuel tanker and park it ~80m away from the lander module, then switched back to the lander module to perform the docking manoeuvre.
Now look at how much fuel there is left in this thing. Given that it's a nuclear engine powering this, there's loads left. I had been planning, at this stage, to jettison the lander's fuel tank and engine to save mass, but I changed my mind. It occurs to me at this point that I could be cocky and do a landing on Ike as well.
Getting into a ~45km orbit around Ike:
Annoyingly, the sunlit side is facing away from Duna, and I want to land on the sunny side (because I need to see the shadow to judge altitude), and with a view of Duna in the sky for photo-taking purposes. So I need to wait while it completes 1/4 to 1/3 of an orbit.
Jeb once again poses for publicity shots, Duna hanging in the sky behind him. Ike and Duna are tidally locked to one another, so Duna will always stay in that part of the sky. Time accelerating, I notice a small amount of libration, but for all intents and purposes, it's fixed in that direction. Well, there's only so much to see on Ike, so our heroes eventually depart this barren airless rock.
Docked once again with my fuel tanker:
The fuel levels are somewhat lower now - I used up a fair amount getting down to Ike and back up again. I transfer the remaining fuel and mono-propellant in the lander into the fuel tanker, and jettison the engine and tanks. It's time to go home. Or at least, it will be once the planets align appropriately.
Alas, I misjudged the return trajectory from Ike, and ended up departing early. Turns out all the maths in the world won't help you if it's practically impossible to accurately measure angles in this game. I had to circularise and let Kerbin catch up with me like with an orbital rendezvous. Such a waste of fuel - good thing I brought plenty with me.
Now there's a sight for sore eyes. Our three Kerbalnauts clap eyes on their home planet for the first time in 505 days. I'm sure our heroes are keen to once again breathe fresh air after a year and a half in a cramped capsule with each others' farts and no way to open the window.
Back safely on the ground, our heroes pose for one last photograph. That minuscule capsule is all that remains of the magnificent vehicle that took them to two other worlds.
