We choose to go to the Moon a week after Kennedy's assassination. The idea of a joint Moon mission was abandoned after Kennedy's death, but the Apollo Project became a memorial to him. His goal was fulfilled in July 1969, with the successful Apollo 11 Moon landing. This accomplishment remains an enduring legacy of Kennedy's speech, but his deadline demanded a necessarily narrow focus, and there was no indication of what should be done next once it was achieved. Apollo did not usher in an era of lunar exploration, and no further missions were sent to the Moon after Apollo 17 in 1972. Subsequent planned Apollo missions
Moon landing are not required. However, a manned circumlunar loop trip poses significant challenges above and beyond those found in a manned low-Earth-orbit mission, offering valuable lessons in preparation for a manned Moon landing. Foremost among these are mastering the demands of re-entering the Earth's atmosphere upon returning from the Moon. Manned Earth-orbiting vehicles such as the Space Shuttle return to Earth from speeds of around . Due to the effects of gravity, a vehicle returning from the Moon hits Earth's atmosphere at a much higher speed of around . The g-loading on astronauts during the resulting deceleration can be at the