Don was a chief scientist in the aerospace industry. His career started when he was a teenager and fired a rocket in the Mojave Desert that scrambled jets from Edwards Air Force Base. He was kicked out of the Junior Rocket Club and got into Stanford (he believed) from this activity. He worked with solid, liquid, hydrated and nuclear rocket engines as a systems engineer and had the only existing patents on his nuclear engines. He also was a rocket course teacher and wrote many, many technical papers for AIAA. He is internationally recognized for his contributions.