The Day a NASA Rocket Almost Exploded - Mercury Redstone 1

Video from the channel Overlook Horizon about Mercury-Redstone 1, linked on its Above Ten Thousand entry. Duration: 3:12. Language: English. Video type: Documentary.

Short explainer piece about the first failed attempt of Mercury-Redstone 1, known as the "four-inch flight."

In November 1960, as part of Project Mercury, it was to be the programme's tenth uncrewed test flight and was meant to qualify the capsule and its launch vehicle for suborbital missions.

After ignition, two ground electrical cables disconnected in the wrong order; the rocket interpreted this as meaning it had already flown and shut down the engine after rising 3.8 inches. The escape tower shot up to about 4,000 feet and the capsule opened its parachutes, with the rocket still fuelled on the pad. Shooting holes in the tanks was ruled out, and they waited for the oxidizer to boil off. A 12-inch ground strap designed to disconnect last was added afterward, and the capsule flew on the next test.