| Little Joe 1A | |
| Insignia: | Mercury insignia.png |
| Mission Type: | Abort test |
| Operator: | NASA |
| Mission Duration: | 8 minutes, 11 seconds |
| Distance Travelled: | 11.5miles |
| Suborbital Apogee: | 9miles |
| Spacecraft Type: | Mercury boilerplate |
| Manufacturer: | McDonnell Aircraft |
| Launch Mass: | 1007kg (2,220lb) |
| Launch Date: | UTC |
| Launch Rocket: | Little Joe |
| Launch Site: | Wallops LA-1 |
| Landing Date: | UTC |
| Previous Mission: | Little Joe 6 |
| Next Mission: | Little Joe 2 |
| Programme: | Project Mercury Abort Tests |
Little Joe 1A (LJ-1A) was an uncrewed rocket launched as part of NASA's Mercury program on November 4, 1959.[1] This flight, a repeat of the Little Joe 1 (LJ-1) launch, was to test a launch abort under high aerodynamic load conditions. After lift-off, the pressure sensing system was to indicate when the correct abort dynamic pressure was reached.[2] This should have happened about thirty seconds after launch.[2] A signal was sent to the explosive bolts to separate the spacecraft from the launch vehicle.[2] Up to this point, everything was going as planned.[2] The impulse was also intended to ignite the escape motor.[2] The motor was ignited, but it took a number of seconds to build up thrust, and thus the abort maneuver was not accomplished at the desired dynamic pressure.[3] Because of this, a repeat of the test was planned. Other events from launch through recovery occurred without incident.[3] An altitude of 9 statute miles (14.5 km) and a range of 11.5 statute miles (18.5 km) were obtained, and a speed of 2,021.6 miles per hour (3,254 km/h) was reached. Flight time 8 minutes 11 seconds.[4] Payload 1,007 kg.