Mercury-Redstone 1 was a test flight of an unmanned Mercury capsule mounted on a Mercury-Redstone launch vehicle conducted on November 21, 1960. It failed in a most unusual manner.
Ignition occurred on schedule at 0900. But the engine shut down almost immediately. The rocket rose about four inches then settled back down on the launch pad. It remained upright and did not explode.
However, the escape rocket on top of the capsule fired, rose about 4000 ft then landed about 400 yards away. The Mercury capsule, still atop the Mercury-Redstone launch vehicle, deployed its parachutes.
This left a fully fueled rocket with a live self destruct system and the Mercury capsule's retrorockets intact. After waiting for the the flight batteries in the rocket and capsule to run down and the Redstone's liquid oxygen to burn off, the rocket was rendered safe by technicians. As the flight director, Chris Kraft, said, "That is the first rule of flight control. If you don't know what to do, don't do anything."
Obviously this was a low point of Project Mercury. But several lessons were learned from the failure to prevent it from happening again.