The Sinking of Liberty Bell 7: Gus Grissom’s Near-Fatal Mission

Jeff Bezos’ successful spaceflight in the New Shepard capsule, and Richard Branson’s nine days earlier in the Unity spaceplane, may finally open the door to more frequent access to space. Both Bezos’ Blue Origin and Branson’s Virgin Galactic have been trying for years to make suborbital flights—short, arcing journeys just beyond the sensible atmosphere—safe enough to sell seats to people wealthy enough to afford it. Accelerating someone to over 2,000 mph (3200 km/h) and then bringing them down unharmed is no easy feat.

Sixty years ago, the U.S. government made the first suborbital flights as part of the Space Race with the Soviet Union. On May 5, 1961, Alan Shepard—the namesake for the Blue Origin launch vehicle and spacecraft—became the first American in space. Hurled by an Army Redstone ballistic missile, Shepard’s Mercury capsule went higher and faster than did the crews of the recent 2021 flights, although Shepard’s accomplishment was overshadowed by the Soviets orbiting Yuri Gagarin three weeks earlier.

On July 21, 1961, Virgil I. “Gus” Grissom flew the second NASA Mercury-Redstone mission. But that trip, nearly identical to Shepard’s almost ended in disaster. Grissom’s capsule, Liberty Bell 7, sank after the successful splashdown in the Atlantic, and Grissom came close to drowning. The six Mercury flights from 1961-1963 produced several nerve-racking moments, but Grissom’s was the only one that came close to killing an astronaut.

Gus Grissom was a gruff, compact, working-class kid from Mitchell, Indiana, who used the GI Bill to become an engineer, fighter pilot, and test pilot. He flew 100 combat missions in Korea. Picked as one of the first seven astronauts in 1959, he made the further cut to the three who would make the initial flights. Project Mercury head Robert Gilruth picked Alan Shepard to be first and Gus Grissom second—much to the frustration of John Glenn, who became the backup for both of them. All were expected to make suborbital Mercury-Redstone flights. The space agency wanted to gain space experience before putting an astronaut in orbit with the larger Atlas missile, the core objective of Mercury — a mission Glenn famously ended up doing, instead of another suborbital trip.

In mid-July 1961, after three weather-related postponements, Grissom finally got to fly. There were two major differences between the Mercury capsule he piloted and the Freedom 7 one flown by Shepard: Liberty Bell 7 had a window over the astronaut’s head instead of two small portholes and a hatch that could be explosively separated for a quicker escape. Lifting off from Cape Canaveral, Florida, about 8:20 am Eastern on July 21, he reached a velocity of 5,134 mph (8,266 km/h) when his Redstone shut down as planned. Liberty Bell 7 then separated. Grissom coasted in weightlessness up to an altitude of 118 miles (190 km) before his capsule began to descend. Riding backwards, he was fascinated and distracted by the beautiful view of Florida out the bigger window. Once the capsule began reentering the atmosphere, the deceleration was brutal, reaching 11 times the force of gravity. Everything worked normally, his capsule’s parachutes deployed, and he landed in the ocean 15 minutes and 37 seconds after liftoff.

It was not long after splashdown that things suddenly went bad. A Marine helicopter from the carrier USS Randolph came in to initiate the pickup of Grissom and his capsule. The plan was to hook on to the capsule, lift it out of the water a little so Grissom would blow off the hatch and then climb out and get into a “horse collar” sling and be pulled up to the aircraft. To hook on, the helicopter crewman had to snip off a long recovery radio antenna that had deployed from the cylindrical nose section of the capsule. As the crewman reached down with an extension cutter, like those used to trim tree branches, the hatch of the spacecraft below suddenly blew off. Seawater began pouring over the hatch rim. Grissom, who had armed the hatch and removed the restraint on the plunger to trigger it, claims he did nothing to initiate the explosion. He had his helmet off and had rolled up the neck dam to keep water from getting down his spacesuit, but had forgotten, or did not have the time, to close the oxygen vent on his suit torso—the attachment point for the capsule oxygen supply.

Grissom instantly threw himself out the hatch and swam away from the sinking spacecraft. The helicopter crew, thinking he was ok and following their training, moved in to hook on to Liberty Bell 7. But the water flowing into the capsule made it too heavy for the helicopter, which at one point had all three wheels in the water. The pilots got an engine overheating warning light. Forced to unhook, the crew watched the capsule slip beneath the waves. Grissom, meanwhile, found himself slowly sinking too. As water leaked in through the oxygen inlet, he gradually got lower and lower in the water. Blasted by the rotor wash, Grissom waved frantically to the helicopter. After Liberty Bell 7 sank, and fortunately before Grissom did, the crew came back and lowered the sling. The wet and exhausted astronaut was taken back to the carrier.

Almost immediately afterward, rumors circulated that Gus Grissom had panicked and triggered the hatch himself. He repeatedly testified that he was lying in his couch waiting for the helicopter when it “just blew.” The space agency’s investigations, which notably lacked the capsule resting at the bottom of the ocean, provided no other evidence. Given that hitting the plunger hard enough to trigger the hatch often caused a nasty bruise on the hand, something Grissom did not have, NASA leadership was inclined to believe him. Because Shepard was sidelined with an inner-ear problem from 1964 to 1969, Gus went on to command the first two-astronaut mission in 1965. With a wink, he named Gemini 3 Molly Brown, after a contemporary Broadway musical, The Unsinkable Molly Brown. (A humorless NASA banned further spacecraft names in Project Gemini.) He then was to command the first crewed Apollo mission, but was tragically killed in a launch-pad fire in January 1967, along with Ed White, the first American to walk in space, and Roger Chaffee.

In 1979, when Tom Wolfe published The Right Stuff, his bestselling account of test pilots and astronauts, it gave new life to the panic rumors, amplified by the 1983 movie version. But that always seemed unlikely for a seasoned pilot like Grissom. When Curt Newport’s Oceaneering International recovered the capsule in 1999, in an expedition funded by the Discovery Channel, no new conclusive evidence about the hatch was found during conservation. Recently however, surviving members of the helicopter crew have reported they saw a flash when the cutter touched the antenna. Rotor wash can create a static charge on helicopters, which may have discharged through the spacecraft and tripped the explosive in the hatch seal. A new investigation has provided further evidence that this is likely to be true.

Today Liberty Bell 7 is in a special display case at the Cosmosphere in Hutchinson, Kansas, the only Mercury, Gemini, or Apollo spacecraft flown by astronauts that the National Air and Space Museum does not own. In a deal to facilitate the capsule’s recovery and conservation, the Museum and NASA voluntarily gave title to the Cosmosphere, which is a Smithsonian Affiliate with extensive experience conserving early U.S. human spacecraft. We have often worked closely with our Kansas colleagues on such projects. If you are ever in the middle of America, it is well worth visiting Liberty Bell 7, a silent witness to the second U.S. human spaceflight, and the first one that was nearly fatal.

Michael J. Neufeld is a senior curator in the Museum’s Space History Department and is responsible for Mercury and Gemini spacecraft, among other collections.