Carpenter served as backup pilot for John Glenn's Mercury-Atlas 6 mission and then flew Aurora 7 on Mercury-Atlas 7 in 1962. He became the second American to orbit Earth and the fourth American in space. The mission completed three orbits, but fuel-management and spacecraft-control problems contributed to Aurora 7 landing far downrange from the planned recovery area.

Although the flight returned Carpenter safely, the downrange landing and disagreements over spacecraft operation affected his later NASA flight opportunities. He remained part of the Mercury story as both a skilled pilot and a reminder that early orbital flight still involved uncertain procedures, limited automation, and difficult judgment calls in real time.

Carpenter later moved into undersea exploration through the Navy's SEALAB program. He lived and worked underwater as an aquanaut and helped connect astronautics with ocean engineering, showing how pressure, isolation, life support, and exploration overlapped across space and sea.

Carpenter's career is important because it widened the definition of exploration around the Mercury generation. He flew one of NASA's first orbital missions, backed up the first American orbital flight, and later carried the same operational mindset into undersea research.