Liberty Bell 7

Liberty Bell 7 repeated the suborbital flight profile that had carried Alan Shepard into space two and a half months earlier, this time with Gus Grissom at the controls. Launched from Cape Canaveral on July 21, 1961, the mission followed the same ballistic arc as Freedom 7, reaching a peak altitude of over 118 miles and giving Grissom a similar window of weightlessness before a fiery reentry and parachute descent into the Atlantic.

The flight itself went almost exactly as planned. Grissom successfully tested manual control of the spacecraft and executed the mission's technical objectives without significant incident. It was what happened after splashdown that turned Liberty Bell 7 into one of the most talked-about flights of the early space program.

Moments after the capsule settled into the ocean, the explosive hatch blew open unexpectedly. Seawater rushed into the cabin, and Grissom had to scramble out into the ocean as the capsule began taking on water and losing buoyancy. His spacesuit, designed to be watertight, began filling with water through an open oxygen inlet valve he had left unlatched for ventilation, dragging him down and turning what should have been a routine swim into a genuine fight to stay afloat.

A recovery helicopter attempted to hook and lift the flooding capsule but could not overcome its rapidly increasing weight, and the pilots were forced to release it to avoid crashing into the ocean themselves. Liberty Bell 7 sank in roughly 15,000 feet of water while a second helicopter pulled an exhausted Grissom from the sea. He survived without serious injury, but questions about what caused the hatch to blow, and whether Grissom had activated it himself, followed him for years.

Liberty Bell 7's flight validated the same suborbital profile Freedom 7 had proven two months earlier, but its dramatic aftermath left a lasting mark on how NASA thought about spacecraft hatch design and crew egress procedures.

The near-loss of Grissom in the ocean underscored how quickly a routine recovery could turn dangerous, and it influenced engineering discussions carried forward into later Mercury, Gemini, and Apollo hatch designs, which prioritized crew safety during both nominal and emergency scenarios.

For Grissom personally, the mission's ending cast an unfair shadow over an otherwise successful flight, with questions about the hatch following him despite no evidence he was at fault. He went on to fly Gemini 3 and was selected to command Apollo 1, cementing his place as one of the most trusted pilots in the astronaut corps before his death in the January 1967 launch pad fire.

The eventual recovery of Liberty Bell 7 in 1999 gave the public a rare chance to see a flown Mercury capsule up close, preserving a physical piece of one of the space program's most dramatic early moments.