On July 18, 2011, about 1215 central daylight time, a Mooney Aircraft Corp., M20S, N442PT, experienced a hard landing following an attempted go-around maneuver at the San Antonio International Airport (SAT), San Antonio, Texas. The commercial pilot, the sole occupant, was seriously injured. The airplane sustained substantial damage to the fuselage. The airplane was registered to and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed for the flight, which operated without a flight plan. The cross-country flight was concluding at SAT when the accident occurred. According to the pilot, during his first attempted landing the airplane began to porpoise on the runway and he performed a go-around. Following the second approach the airplane touched down to the runway and again began to porpoise. The pilot reported that he attempted to execute another go-around by applying full engine power; however, the left landing gear would not retract and the airplane began to yaw left and descend. When the airplane started to bank “uncontrollably” to the left, the pilot elected to land in the grass alongside the runway. The pilot further added that during the landing he fractured a vertebra in his back. An eyewitness reported observing the airplane struggling to maintain altitude as it appeared to be “pulling out of a landing.” The landing gear was retracted as the airplane tried to gain altitude as if the pilot had realized at the last moment that his landing gear was not down. As the airplane attempted to climb, it was tilting from side to side while at an approximately 70 degree nose high angle. The airplane’s tail impacted the ground first followed by the fuselage belly. The airplane then bounced about 15 feet into the air before settling back to the ground. A Federal Aviation Administration (FAA) inspector examined the airplane. The inspector reported that the airplane came to rest upright with the landing gear retracted. The airplane was raised and the gear lowered normally. The inspector was unable to find any preimpact anomalies with the airplane.