Mercury-Atlas was a subprogram of Project Mercury[1]: 1  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.

[2]: 207 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: