Ronald L. Sheffield has loved airplanes since he was very young. He graduated from the University of Oklahoma with a degree, ROTC commission, and a private pilot's license in 1962. He served in the Army as an infantry aviator from 1962-1982. He served three, one year tours in Vietnam primarily in armed helicopters (1965-66; 1967-68; and 1971-72). In Vietnam, he commanded two armed helicopter platoons and a Cobra Attack Helicopter Company while acquiring 2200 hours of combat time. His awards include a Silver Star, Distinguished Flying Cross, two Bronze Stars, two Meritorious Service Medals, 59 Air Medals plus a Valor device, Army Commendation Medal, National Defense Service Medal, Expeditionary Forces Medal, Vietnam Service Medal w/9 stars, two Vietnamese Cross of Gallantry with Silver Star, Vietnamese Honor Medal 1st Class, and Vietnam Campaign Medal. His unit awards include two Presidential Unit Citations, Valorous Unit Award, Meritorious Unit Commendation, and two Vietnamese Cross of Gallantry with Palms. He earned Master Army Aviator and Senior Parachutist wings. He served as an Air Officer Commanding of a cadet squadron at the USAF Academy (1975-1978). He is qualified in 6 types of Army helicopters and 4 fixed wing aircraft.

After Army retirement, he worked as a trainer at the Satellite Control Facility and engineer on the MX Missile. In 1985, he went to work for Lockheed on the Hubble Space Telescope (HST). His task was to upgrade every electrical and mechanical component on the HST so that it could be replaced on-orbit. As the Extravehicular Activity (EVA) Manager for the HST, he was responsible for the initial EVA procedures and training of the astronauts to accomplish the repair and servicing of HST. He trained 41 astronauts how to accomplish six HST missions from 1990 thru 2009. His awards included the Astronaut Award (The Silver Snoopy), NASA's highest award (Distinguished Public Service Medal), two of Lockheed Martin's highest awards (Nova Award), an American Institute of Aeronautics and Astronautics 1994 Aerospace Maintenance Award, and Lockheed Technical Operations Presidential Award. He also received numerous NASA Team awards for the HST missions.