4. Project Mercury began with a series of booster failures
Three different rocket boosters were used for the Mercury program, and all of them were problematic at times. The Redstone booster was used for the suborbital flights of Alan Shephard and Virgil Grissom, while the Atlas booster was designated for the later orbital flights. Both failed catastrophically in testing with the Mercury capsule in unmanned flights in 1960 and 1961. On April 25, 1961, less than two weeks prior to Shepard’s planned flight (using a Redstone booster) a test of the Mercury capsule in an unmanned orbital flight was aborted when its Atlas booster failed to pitch and roll downrange, instead continuing to climb straight up in the air.
The vertical climb meant that when the rocket exploded the resultant debris would rain straight down on Cape Canaveral and the nearby town of Cocoa Beach. The higher the altitude at the time of destruction the wider the area of the debris field would be. The capsule itself used an escape rocket when the booster was destroyed deliberately by the flight controller, and was later recovered by naval salvage. Materials from the destroyed booster rained down from the sky. Two months after the aborted flight, materials in various sizes and weights were still being found buried in the beaches and other areas surrounding the launch facility. There were no personnel casualties from the incident, but the reliability of the boosters was clearly questionable as preparations for manned flight went ahead.