Has been a while, but I fondly remember my first (and so far only) manned duna mission. All went well, but I used more fuel than expected during landing (due to the inefficency of the parachutes). I barely made it into orbit and my return vessel had to go into a much lower orbit to pick up the crew. I barely had any fuel left when I got back into Kerbin SOI and only got Pe into Atmosphere so closely. Took a few (long) orbits to finally land. (To be fair, I gave no .... about transfer windows, so I could have made it much more safe)