@ Biotronic: Good to know that, thank you (but i still dont find it explained in the OP) @ funk: I had exactly the same problem today. I tried to land it with HyperEdit and it just exploded. I had no ohter autosave so I started new all over to get Jeb back.^^ (was one of the first misssions, so not that bad) But I can't remember I used TweakScale on that rocket. I have no copy of the log files or anything (as long as I know, since I deleted that savegame). Maybe this is not a TweakScale Problem.