Complex sentence: Occultists cite Parsons as one of the most significant figures in propagating Thelema across North America, while scientific historians recognize his contributions to rocket propulsion chemistry and design, and his pioneering advocacy for their use in space exploration and human spaceflight.
Split into simpler sentences: Occultists cite Parsons as one of the most significant figures in propagating Thelema across North America. Scientific historians recognize his contributions to rocket propulsion chemistry and design, and his pioneering advocacy for their use in space exploration and human spaceflight.