Mercury-Redstone 4

Mercury-Redstone 4

Astronaut Gus Grissom climbs into Liberty Bell 7
Mission type	Test flight
Operator	NASA
Mission duration	15 minutes, 37 seconds[1]
Range	262.50 nautical miles (486.15 km)
Apogee	102.76 nautical miles (190.31 km)
Spacecraft properties
Spacecraft	Mercury No.11
Manufacturer	McDonnell Aircraft
Launch mass	2,835 pounds (1,286 kg)
Crew
Crew size	1
Members	Virgil I. Grissom
Callsign	Liberty Bell 7
Start of mission
Launch date	July 21, 1961, 12:20:36 (1961-07-21UTC12:20:36Z) UTC
Rocket	Redstone MRLV MR-8
Launch site	Cape Canaveral LC-5
End of mission
Recovered by	USS Randolph
Landing date	July 21, 1961, 12:36:13 (1961-07-21UTC12:36:14Z) UTC
Landing site	North Atlantic Ocean 27°32′9″N 75°45′57″W / 27.53583°N 75.76583°W / 27.53583; -75.76583
Spacecraft name as painted on capsule side, with a "crack" Virgil Ivan "Gus" Grissom Project Mercury Crewed missions ← Mercury-Redstone 3 Mercury-Atlas 6 →

Mercury-Redstone 4 was the second United States human spaceflight, on July 21, 1961. The suborbital Project Mercury flight was launched with a Mercury-Redstone Launch Vehicle, MRLV-8. The spacecraft, Mercury capsule #11, was nicknamed Liberty Bell 7. It was piloted by astronaut Virgil "Gus" Grissom.

The spaceflight lasted 15 minutes 30 seconds, reached an altitude of more than 102.8 nautical miles (190.4 km), and flew 262.5 nautical miles (486.2 km) downrange, landing in the Atlantic Ocean. The flight went as expected until just after splashdown, when the hatch cover, designed to release explosively in the event of an emergency, accidentally blew. Grissom was at risk of drowning, but was recovered safely via a U.S. Navy helicopter. The spacecraft sank into the Atlantic and was not recovered until 1999.