I'm a veteran, I've been althroughout the solar system, but I think my best achievement was early on in career mode. I had a rocket trying to land on the moon, but I realized when I was about five hundred meters from the ground that I had no battery, and no landing gear. So like any science-hungry pilot, I set my rocket at a low level of thrust so it would slowly fly back upwards while I jumped out of the crew hatch. I flew down, nabbed a surface sample, then jet packed back up to my rocket. That part was a bit difficult, as it started rotating and picking up speed. I managed to get in though, and fly back home.