Complex sentence: Contrary to popular belief, Jefferies did not create "Star Trek"'s original shuttlecraft design: although Jefferies submitted his own concept, it was too complex to build with the show's shoestring budget.
Split into simpler sentences: Contrary to popular belief, Jefferies did not create "Star Trek"'s original shuttlecraft design. Although Jefferies submitted his own concept, it was too complex to build with the show's shoestring budget.