In September 1966, he entered active duty with the United States Marine Corps Reserve. He achieved the rank of Captain in 1967, was designated a naval aviator in 1968, and was subsequently assigned to duty flying F-4s with VMFA-333 at Marine Corps Air Station, Beaufort, South Carolina. He flew 163 combat missions in Vietnam while assigned to VMFA-115 from January 1969 to 1970. He returned to the United States and an assignment as aviation weapons division officer with VMFA-251 at the Marine Corps Air Station, Beaufort, South Carolina.
Thagard resumed his academic studies in 1971, pursuing additional studies in electrical engineering, and a degree in medicine; prior to coming to NASA, he was interning in the Department of Internal Medicine at the Medical University of South Carolina. He is a licensed physician.
He is a pilot and has logged over 2,200 hours flying time--the majority in jet aircraft.
Birth Place: Marianna, Florida.
Spaceflights: 5 .
Total time in space: 140.56 days.
Mission Specialists: Bachelor's degree in engineering, biological science, physical science or mathematics and minimum three years of related experience or an advanced degree. Vision minimum 20/150 uncorrected, correctable to 20/20. Maximum sitting blood pressure of 140/90. Height between 150 and 193 cm.. 8,079 applicants, of which half met the basic qualifications. 208 invited for physical tests and interviews. Of the 35 selected, six were women, three were male African-Americans, and one was a male Asian-American.