Apollo 4

On November 9, 1967, NASA launched Apollo 4, the first flight test of the gigantic Saturn V. The Saturn V was the rocket that took Apollo astronauts to the moon. Standing 363 feet and weighing 6 million pounds when fully fueled, the Saturn V dwarfed anything previously launched.

The Saturn V had three stages. Stage 1, called the S-IC, was 138 feet long and 33 feet in diameter. It had five monstrous F-1 engines. Each generated just over 1.5 million pounds’ thrust, giving the Saturn a lift off thrust of 7.6 million pounds. Liquid oxygen and RP-1 kerosene fueled the F-1’s. The second stage, or S-II, also had five engines, but they were much smaller, the J-2. Burning liquid oxygen and liquid hydrogen, each J-2 produced a thrust of 200,000 pounds to give the S-II a thrust of 1 million pounds. A single J-2 powered the third and final stage, the S-IVB.

The Apollo 4 S-IC was assembled at the Marshall Space Flight Center in Huntsville, Alabama. Empty, the stage weighed nearly 300,000 pounds; fully fueled, it weighed in at five million pounds. The five F-1s burned 2,230 gallons of propellants every second. Four of the engines were mounted equidistantly around the center engine. The four outboard engines were gimbaled to steer the rocket; the center engine was fixed in place.

North American Rockwell Corporation’s Space Division built the S-II stage. Like the first stage, four of the J-2 engines surrounded the central one. The four outboard engines could be gimbaled plus or minus 7 degrees to keep the rocket on course.

The S-IVB stage was built by the McDonnell Douglas Astronautics Corporation. It weighed 25,000 pounds empty and 262,000 pounds fully fueled.

Such a gigantic rocket needed a unique suite of ground facilities, so NASA built Launch Complex 39. Complex 39 introduced the mobile concept of launch operations to the American space program. Previously, technicians assembled the rockets and their payloads vertically on the pad, leaving the vehicles exposed to the weather for weeks or even months. Using the mobile concept, something the Soviets had done for years, the Saturn was checked in an enclosed building before being moved to the pad.

NASA constructed the Vehicle Assembly Building (VAB), for Saturn V assembly and check out. Measuring 716 feet long by 518 feet wide and 525 feet tall, the VAB could contain four rockets at one time. Everything associated with the VAB was built on a massive scale. Its construction required 4,225 16-inch steel pilings, each one driven 160 feet through the sandy soil into bedrock, and it covered 8 acres. The launch control center for the Saturn adjoined the VAB. This, too, was a radical departure from past launch pad architecture. The Apollo launch control center looked more like a glass-front office building than one of the older, igloo shaped concrete blockhouses.

Saturn V’s were stacked on a mobile launch platform in the VAB. Moving the Saturn and its mobile platform from the VAB to the launch pad required a huge tracked vehicle, the Crawler Transporter, that was 114 feet wide. Each cleat in the Crawler Transporter’s tracks weighed just over one ton. Maximum speed for the transporter was about one mile per hour when loaded. An unfueled Saturn V and mobile launch platform weighed 6,000 tons; the Crawler Transporter by itself weighed 3,000 tons! Launch Pads 39A and B were three and a half miles from the VAB. A special 131-foot wide roadbed topped with river rock from Alabama connected the assembly building and launch pads. The gravel helped distribute the load on the transporter bearings and reduced friction during steering. It took about six hours to reach the pad because maximum speed was not maintained throughout the trip.

When Apollo 4 lifted off at 7:00:01 AM EST on November 9, 1967, the roar was so tremendous that is shook plaster loose in the network news trailers alongside the VAB. For the first time, the world witnessed the take off of a rocket weighing 6 million pounds. With the first launch of the Saturn V, NASA adopted a philosophy of “all up testing.” What that meant was that all three stages of the rocket were functional. Previously, the first flight of a new multistage rocket typically only had the first stage live. Only after the first stage’s performance was verified were live upper stages added. George Mueller, who headed NASA’s Office of Manned Space Flight, advocated testing all three stages on the first flight, as a measure to save both time and money. Mueller’s judgment had been correct; Apollo 4 was a success.

The S-IVB inserted the spacecraft, Apollo Command Module 017, into a circular orbit approximately 11 minutes after liftoff. Near the end of its second orbit, the S-IVB fired again, placing the spacecraft into an elliptical orbit with an apogee of 9,292 miles. After the Command and Service Modules separated from the spent booster, the Service Propulsion System engine fired for 15 seconds, raising the apogee slightly. The spacecraft then flew with its outer hatch facing the sun for the next 4-1/2 hours to collect thermal data.

After 8 hours and 10 minutes of flight, the Service Propulsion System engine fired again to increase the spacecraft’s speed to 25,000 miles per hour. This was the speed of an Apollo spacecraft returning from the moon. This was the most severe test of the Apollo heat shield thus far. Apollo 4 survived the reentry and splashed down within five miles of the predicted landing point. The crew of the USS Bennington recovered the Command Module, bringing the flight to a successful conclusion. Pronounced a complete success, Apollo 4 was an important step for America’s lunar landing program.