The National Aeronautics and Space Administration (NASA) has often acknowledged the efforts of the thousands of men women in many organizations all over the world who make manned space missions possible, U.
The National Aeronautics and Space Administration (NASA) has often acknowledged the efforts of the thousands of men women in many organizations all over the world who make manned space missions possible, U.S. Air Force support at Cape Kennedy, Florida, during launch tracking, and recovery operations, for instance, is generally well known. What isn't so well know, however, is the work on the Apollo program that has been going on at Air Force Systems Command research and development facility in the middle of Tennessee.
The station is the Arnold Engineering Development Center at Tullahoma where testing on the Apollo has been underway since June of 1960.
This is a high altitude simulation cell for testing rocket engines. It's the largest test cell at Arnold and has been used almost exclusively since March of 1966 to develop and perfect the J-8 engine for the S-II and S-IVB stages of the Saturn rocket.
The S-IVB, or third, stage of the Saturn V is powered by a single J-2 engine, which develops 200,000 pounds of thrust. This stage measures slightly more than 58 feet in length and is 22-3/4 feet in diameter.
The inclusion of this engine's propellant tankage makes it the largest vehicle ever tested in this country in an environmental test cell. This battleship tankage weighs more than 60 tons and holds some 230,000 pounds of propellant.
The J-2 engine, built by Rocketdyne, is called upon to ignite, coast, gimbal, and restart in space. The purpose of this series of tests is to prove the reliability of the entire system under simulated altitude and temperature conditions.
During the J-2 test program, the engines have been fixed about 200 times for periods from five to 50 seconds. The tests used about 4000 tons of propellants.
The Service Module on the Saturn is tested at another cell at the Arnold Center. This contains the engine that will be used to make mid-course corrections if any are needed on the trip to the moon and return. As the astronauts approach the moon, it will be used to put them in a parking orbit where the command and service modules will remain until the two astronauts aboard the Lunar Module return from the moon. Finally, the service module engine is used to put the astronauts on course to the earth, after which the entire service module is jettisoned when the command module is prepared for reentry.
Tests at the Arnold Center began in 1962, using engines that were scaled down to one-third size. Purpose of these tests was to help NASA in selecting a contractor for the real thing.
Full-scale engine testing began in 1963 after the manufacturer was selected. Early tests were aimed at developing the nozzle.
The nozzle on this engine is of such lightweight construction that it cannot be tested under the relatively heavy pressure of sea level atmosphere. This is one of the first nozzle tested in a simulated high altitude environment.
All of this testing has one ultimate goal....successful Apollo missions.