Complex sentence: The design also originally included a complex engine design to continue the theme of a more scientifically realistic approach, as it was necessary to accurately portray how such a massive spacecraft, with a large rotating section, could maneuver.
Split into simpler sentences: The design also originally included a complex engine design to continue the theme of a more scientifically realistic approach. As it was necessary to accurately portray how such a massive spacecraft, with a large rotating section, could maneuver.