When Gus Grissom climbed into the cockpit of his Mercury spacecraft on the morning of July 21, 1961, he was ready for an adventure. Grissom's Mercury mission (MR-4) was the second of the series, and like Alan Shephard before him, it was a sub-orbital lob. The Redstone rocket would take Gus and his spacecraft, dubbed Liberty Bell 7, above the atmosphere, but not quite fast enough to achieve orbit. The launch was on time and perfect, as was the short period of weightless flight, and re-entry through the atmosphere. Liberty Bell 7 deployed its main parachute as expected and landed within two miles of the Navy recovery team. Gus secured the spacecraft and waited to be rescued. However, without warning, the explosive hatch blew off and the spacecraft begin to take on water. Grissom escaped but nearly drowned in his spacesuit. Liberty Bell 7 filled with seawater and sank to the bottom of the Atlantic. It was the only NASA spacecraft ever lost at sea.