 On April 24, the single pilot of Soyuz 1, Vladimir Komarov, was killed in a crash when his landing parachutes tangled, after a mission cut short by electrical and control system problems.Both accidents were determined to be caused by design defects in the spacecraft, which were corrected before crewed flights resumed.The US conducted the first crewed spaceflight to leave earth orbit and orbit the Moon on December 21, 1968 with the Apollo 8 space mission.