Apollo 4 - Flight

Flight

The vehicle's on-pad, pre-launch tests started in September, and encountered several problems with propellant loading and various equipment failures, pushing the launch into November, but providing valuable lessons learned on the new vehicle's launch operations. On November 6, the 56½ hour countdown sequence began with propellant loading. In total there were 89 trailer-truck loads of LOX (liquid oxygen), 28 trailer loads of LH2 (liquid hydrogen), and 27 rail cars of RP-1 (refined kerosene). This time the problems encountered were few and minor.

Launch occurred on November 9 at 7:00AM EST (12:00PM UTC). Eight seconds before liftoff, the five F-1 engines ignited, sending tremendous amounts of noise across Kennedy Space Center. To protect from a possible explosion, the launch pads at LC-39 were located more than three miles from the Vehicle Assembly Building; still, the sound pressure was much stronger than expected and buffeted the VAB, Launch Control Center and press buildings. Ceiling tiles fell around news reporter Walter Cronkite, covering the launch for CBS News booth. NASA later built a sound suppression system that pumped thousands of gallons of water onto the flame trench under the pad.

The launch placed the S-IVB and CSM into a nearly circular 100-nautical-mile (190 km) orbit, a nominal parking orbit that would be used on the actual lunar missions. After two orbits, the S-IVB reignited for the first time, putting the spacecraft into an elliptical orbit with an apogee of 9,297 nautical miles (17,218 km) and a perigee that would deliberately take it 45.7 nautical miles (84.6 km) below the Earth's surface; this would ensure both a high-speed reentry of the Command Module, and atmospheric reentry and destruction of the S-IVB. The CSM then separated from the S-IVB and fired its Service Module engine to raise the apogee to 9,769 nautical miles (18,092 km) and a perigee of −40 nautical miles (−74 km). After passing apogee, the Service Module engine fired again for 281 seconds to increase re-entry speed to 36,545 feet per second (11,139 m/s), at an altitude of 400,000 feet (120 km) and a flight path angle of -6.93 degrees, simulating a return from the Moon.

The CM landed approximately 8.6 nautical miles (16 km) from the target landing site northwest of Midway Island in the North Pacific Ocean. Its descent was visible from the deck of the USS Bennington, the prime recovery ship.