Bookmarked. It's about time I try to learn how to use this transfer window thing. As for the Duna thing, I had a look and found the thread you talk about, but that sounds tricky. I might go direct for my first attempt to keep it simpler. Thanks, that gives me confidence in that I'll be able to pull this off. I'm going to take my old Mun lander, bolt on the new science things I have and do an Apollo style CM/LM thing I think. If I do a crew-supply using a SSTO spaceplane I won't even need heatshields and chutes. (To coin a phrase, Warzouz - I am smart - most helpful thread, thanks) I might install KER, so I can compare DV's.