Complex sentence: Eight days before Colonel Towel's retirement, President Eisenhower created the National Defense Service Medal retroactive to June 27,1950 which made her eligible for the medal but it is uncertain if she was ever formally awarded it.
Split into simpler sentences: Eight days before Colonel Towel's retirement, President Eisenhower created the National Defense Service Medal retroactive to June 27,1950. She was, thus, eligible for the medal but it is uncertain if she was ever formally awarded it.