Designed as a three stage program. The first flight put a mock crew module on course to flyby duna, and then brought it back to Kerbin, testing the engines and the artificial gravity cabin.
The second flight sent a crew of three to Duna Orbit, and returned them to Kerbin safely. The third flight launched an autonomous lander-base to Duna orbit to await a crew. The Forth launch sent a crew of 4 to Duna orbit, and later to the surface.
5 Ways to Train for Moon Missions
#1 Wide Base
#3 Drop Test
#4 Keep it “lightweight”
#5 Delta-V (delta-v map)