Today in History: April 25

Project Mercury Logo

Mercury-Atlas 3 (MA-3) was an unmanned test flight of the Mercury program. The Mercury program’s goal was to put a man into Earth orbit and return him safely, ideally before the Soviet Union. On April 25, 1961 at 16:15 UTC, MA-3 launched from Launch Complex 14 at Cape Canaveral, Florida carrying a robotic “mechanical astronaut”. The MA-3 was made up of Mercury spacecraft No. 8 and Atlas No. 8 LV-3B 100-D rocket. The rocket used had a number of upgrades, including a thicker skin to support the Mercury spacecraft’s extra weight and a new transistorized telemetry unit which replaced the previous vacuum tube units that were bulky, had high power consumption, and whose signal strength tended to degrade during launch.

Mercury-Atlas 3 Launch

However, even with these improvements, the rocket was still not reliable enough to carry a human to space. At 20 seconds into the flight, the pitch and roll sequence failed to initiate and the vehicle just continued flying straight upward. At 43 seconds into the flight, the flight the Range Safety Officer pushed the self-destruct button and the flight was terminated. MA-3 ended in a rain of fiery debris falling back to Earth. At the moment the self-destruct command was sent, the Mercury capsule was detached from the rocket and continued on downrange 1.1 miles (1.8 kilometers), reaching an apogee of 4.5 miles (7.2 kilometers). The flight of the Mercury capsule lasted 7 minutes and 19 seconds, most of that time descending on its parachute. The capsule was recovered about 20 minutes after launch in the Atlantic Ocean and reused on the next flight (MA-4) as spacecraft No. 8A. The flight wasn’t a complete failure though, it proved that the launch escape system worked. This was the first Mercury-Atlas launch with a live escape tower.

Investigation of the telemetry data quickly narrowed the cause of the failure to a fault somewhere in the guidance system, but the exact nature of it could not be determined. It appeared that the guidance system programmer either shut off completely shortly after liftoff or suffered a power outage, restarted, and then failed to execute the pitch and roll sequence. Two months after the MA-3 flight, the Atlas’s programmer was discovered buried in mud on a beach not far from the launch pad and analyzed. Engineers concluded that the failure was most likely due to contaminated pins in the programmer causing an open circuit. In addition, the Atlas’s guidance system as a whole was found to have a number of serious design deficiencies that needed to be corrected.