Moon Race 2001


Text and pictures from Rockets of the World.

The Saturn V dates back to the Saturn C-5 design of 1961. The smaller C-2, C-3, and C-4 designs were abandoned, but in 1962, NASA approved the development of the Saturn V to fulfill President Kennedy's goal of landing a man on the Moon by 1970. At 363 feet (110.7 m) tall and weighing 6,400,000 lb (2913 metric tons), the Saturn V was the largest rocket ever built.

The first stage was the Boeing S-IC, powered by five Rocketdyne F-1 engines burning kerosene and liquid oxygen. Producing 1,500,000 pounds (6,700,000 Newtons) of thrust, the F-1 was the most powerful single-chamber engine ever built. The F-1 was not meant to be a great technical challenge; it was just a scaled up conventional kerosene oxygen engine. But the scaling up process proved to be more difficult than expected. The engines suffered unstable combustion, oscillating wildly in their burning. In one case, the instability destroyed an engine in a ground test. Rocketdyne and NASA struggled with the problem for four years before a fuel injection system was created that would not only produce a smooth bum, but would even recover from an explosion in the combustion chamber.

The North American S-II second stage proved equally challenging. Five Rocketdyne J-2 engines burned liquid hydrogen and liquid oxygen stored in this stage. Problems with precision welding of the monstrous stage and insulation for its liquid hydrogen tank threatened to delay the whole Apollo program. They were only solved after a reorganization at North American.

The third stage of the Saturn V was the McDonnell-Douglas S-IVB stage powered by a single J-1. Attached to the top of the cylindrical stage was the IBM Instrument Unit, containing the guidance system for the entire rocket.

The Saturn V's Apollo payload comprised the Grumman Lunar Module (LM) concealed at launch in a tapered adapter section. Above this were the Service Module (SM) and Command Module (CM, hidden under the Boost Protective Cover at launch), both built by North American.

The spire of Lockheed's Launch Escape System (LES) topped off the stack.

The first Saturn V to fly was SA-501, carrying the Apollo 4 spacecraft into orbit on November 9, 1967. The rocket performed well, and after two orbits, the S-IVB restarted, sending the Apollo spacecraft into a highly elliptical orbit. The Apollo spacecraft separated, and the CM reentered the atmosphere at the low end of the orbit, testing its heatshield at speed typical of a lunar return.

The second Saturn V did not fly so smoothly. For about 10 seconds near the end of its bum, the first stage underwent "pogo" vibrations so severe that they could have injured astronauts with 10 g accelerations. As soon as the pogo oscillations cleared up, a section of the LM shroud fell free. During the second stage bum, two of the five J-2 engines shut down prematurely. To the surprise and delight of NASA engineers, the vehicle didn't lose control. But the loss of thrust sent the S-lVB pointing in unexpected directions as it fought the with trajectory of the vehicle. At the moment of burnout, it was in fact pointing backwards. While the third stage was able to salvage the mission and place the Apollo spacecraft in orbit, it refused to restart later in the flight.

Mission controllers managed to complete the reentry mission with the SM's engine. While a crew would have survived a flight aboard Apollo 4, SA-502 could not have reached the Moon.

After modifying the first stage engine mounting to eliminate the pogo resonance, redesigning the J-2 fuel lines, and altering the LM shroud design, NASA was ready for the first manned lunar flight, using rocket SA-503. On December 21, 1968, Apollo 8 lifted off, bearing astronauts Frank Borman, Jim Lovell, and Bill Anders. After a full Earth orbit, the S-lVB re-ignited, sending Apollo 8 to the moon. Apollo 8 carried no lunar lander, as this component was not yet ready for flight. On December 24, a firing of the SM's main engine placed the craft in lunar orbit. On Christmas Eve, Apollo 8's crew broadcast images of the Earth from lunar orbit. Millions of television viewers stared at the image of the Earth: some have suggested that the sight of our home planet permanently changed our civilization's world view. After 10 lunar orbits, Apollo 8 fired its engine again, sending it back to Earth.

Apollos 9 and 10 followed, testing the Lunar Module and rendezvous techniques in terrestrial and lunar orbit respectively. But the climax of the Apollo program would have to wait until Apollo 11.

On July 16, 1969, the sixth Saturn V lifted off from Cape Canaveral on the Apollo I I mission. Minutes later, Neil Armstrong, Buzz Aldrin, and Michael Collins entered Earth orbit. After checking their spacecraft and making navigational sightings, the Apollo I I crew were ready to fly to the moon. The S-lVB fired again, sending them on a lunar flyby trajectory. The CSM then separated from the Saturn stage, turned around, and docked with the Lunar Module. The S-lVB was then discarded. On July 19, Apollo 11 entered lunar orbit with a firing of the SM's engine. The next day, Armstrong and Aldrin climbed into the Lunar Module and descended to the lunar surface. Late that evening, the two left the craft for a two-hour walk on the Moon. Armstrong and Aldrin photographed the lunar surface, collected rock and soil samples, and set up experiments before returning to their craft. After a night's fitful sleep, the crew returned to lunar orbit in the top half of the Lunar Module. The Lunar Module and Command Module rejoined, and the crew transferred their lunar samples and film into the CM for the trip home. On July 24, Apollo I I splashed down in the Pacific.

Six more Apollo flights followed. All succeeded except Apollo 13, whose crew returned from a lunar flyby after an explosion in the Service Module. The Apollo program ended with the launch of Apollo 17, on December 6, 1972.

The last Saturn V lifted off on May 14, 1973, carrying the Skylab space station into orbit. The station was built around an S-lVB stage. The upper tank served as living space, while the lower tank was used to store waste. Additional modules were added to the front of the stage, with docking adapters, an airlock, solar telescopes, and additional solar panels. Folded solar panels were also attached to the sides of the S-lVB Orbital Workshop. Skylab replaced the S-lVB stage on the SA-513 rocket.

While the Saturn performed well on this flight, aerodynamic forces ripped off thermal shielding and one solar panel from the Orbital Workshop. The manned crews were able to replace the sunshield and work with the limited solar power to successfully complete the mission. Skylab proved that humans could endure extended space flight. The solar telescopes produced high quality solar images in several wavelengths, and discovered solar coronal holes, as well as other phenomena. Systematic photography of Earth showed the value of space surveys of the world's resources.

Saturn V liftoff
Apollo 11 lifts off on its journey to the Moon.

Saturn V Specifications
Stage 1: 
Thrust7,500,000 lb (33,000,000 N)
Duration170 sec
Impulse1,3000,000,000 lb-sec (5,800,000,000 N-sec)
NAR designation5 x AC 6,700,000
Stage 2: 
Thrust1,000,000 lb (4,500,000 N)
Duration270 sec
Impulse270,000,000 lb-sec (1,200,000,000 N-sec)
NAR designation5 x AB 890,000
Stage 3: 
Impulse100,000,000 lb-sec (450,000,000 N-sec)
NAR designationAC 890,000

If you don't have a copy of Peter Alway's wonderful Rockets of the World, you definitely need one. Material like this, and even more, exists for most rockets built and provides a treasure trove of information for modelers and those interested in space. They can be purchased directly through the publisher, Saturn Press, or at larger bookstores.