On February 27, 1994, approximately 1100 mountain standard time (MST), a Cessna 172, N21840, experienced a hard landing at Gillette-Campbell County Airport, Gillette, Wyoming. The student pilot, who was the sole occupant of the aircraft, was not injured, but the aircraft sustained substantial damage. The local instructional flight, which originally departed the same airport about 90 minutes earlier, was in visual meteorological conditions at the time of the accident. No flight plan had been filed, and there was no report of an ELT activation. According to her instructor, this was the student pilot's second solo flight. The instructor said that during the flight the student had successfully completed 12 or 13 touch-and-go landings prior to the accident. He stated that the accident sequence began when, during an attempted landing, the aircraft began to porpoise. While attempting remedial action to stop the porpoising, the pilot allowed the nose wheel to impact the runway hard enough to cause substantial damage to the airframe.