Mission 21, named Red Planet Landing was the final of the original set of missions. Here, you'll fly to and land on the red planet, RED. This mission is very similar to the lunar landing. You'll need to assemble the N1-LOK-LK vehicle exactly as directed to be able to complete the mission. After docking with the LK lander module in HOM's orbit, fly to RED via LUN. Enter the red planet's orbit, land on the surface, take a picture, and fly to HOM to complete the mission.
The N1-LOK-LK must be assembled as follows: