For those of you having the mechjeb + kethane problems just put mechjeb on your second to last stage of your sat launcher and jettison the mechjeb stage after you have achieved the desired orbit. I have a small ion based kethane survey sat and put mechjeb on the last liquid fuel stage to test and it worked. I also noticed while testing this that the Kethane Grid will come back if you start the game, launch a vehicle from kerbin w/o mechjeb, achive orbit and view the grid once then switch to a vehicle that has mechjeb. not sure if it will be consistent though.