On 16 July 1969, Translunar Injection placed Apollo 11 on a free-return path — a trajectory that uses the Moon's gravity to swing the spacecraft back toward Earth without a major course correction. This classical route was a safety requirement: if the Service Propulsion System failed, Earth's gravity alone would eventually return the crew. Columbia coasted outward for three days, passed behind the Moon's far side, and entered a figure-eight path that arced back toward the Pacific Ocean splashdown. The free-return trajectory exploits the patched-conic approximation — treating the Moon's sphere of influence as a brief gravitational bend in an otherwise heliocentric path — a technique still used in lunar mission planning today.