After joining the Air Force, Lawrence became a test pilot for the MOL (Manned Orbiting Laboratory Program). According to the AMFCSE, Lawrence's work in this program made him a pioneer in what would eventually become NASA's Space Shuttle Program.
The same article states that Lawrence logged over 2,500 hours of flying in his career. NASA shares the story of Robert Lawrence and comments that it's not unlikely that Lawrence even piloted one of the early Space Shuttle missions. Sadly, Lawrence died in an F-104 Starfighter crash in 1967, only two years before man would set foot on the moon for the first time in history.