"In less than 70 hours, three astronauts will be launched on the flight of Apollo 8 from the Cape Kennedy Space Center on a research journey to circle the moon. This will involve known risks of great magnitude and probable risks which have not been foreseen. Apollo 8 has 5,600,000 parts and 1.5 million systems, subsystems and assemblies. With 99.9 percent reliability, we could expect 5,600 defects. Hence the striving for perfection and the use of redundancy which characterize the Apollo program."