Last manned Mercury-Atlas
Mercury-Atlas was a subprogram of Project Mercury that included most of the flights and tests using the Atlas LV-3B launch vehicle. The Atlas was also used for one Mercury flight under the Big Joe subprogram.
The Mercury mission numbering system was: a two-letter designation marking the launch vehicle type, followed by a dash, then a number designating the flight/test number. The Atlas launch vehicles used for Project Mercury were given a two- or three-digit number followed by a "-D", indicating that they were the "D" version of the Atlas.
The missions flown in Mercury-Atlas were: